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TDL A Type Description Language for HPSG Part 2

1. set switch VERBOSE EXPANSION P T 10 SAMPLE SESSION is inconsistent Silent expansion DELTA print slot list don t print delta list cons avm amp FIRST REST list redefine LIST recursively appendO avm amp FRONT gt BACK 1 amp list WHOLE 11 append1 avm amp FRONT lt first resti gt BACK back amp list WHOLE first rest2 gt PATCH append amp FRONT amp resti BACK back WHOLE rest2 append appendO append1 r append FRONT lt a b gt BACK lt c d gt 2 expand type r wait lgp r wait 333 generate LaTeX code set switch VERBOSE EXPANSION P NIL q append amp WHOLE lt a b c gt expand type q fgp q wait result will be in WHOLE compute possible inputs 65 message 74 4List of recursive sccs print recursive sccs message Computing appropriateness table compute approp warn if not unique T print approp Index 1 23 amp 14 16 gt 15 24 14 15 3 27 lt gt 20 lt 12 2 22 23 1 15 17 23 14 16 14 16 18 7 16 22 73 18 accessing internal information infons 38 accessor 39 ACCUMULATE INSTANCE DEFINITIONS 26 28 alias 60 alias 5 42 ALIGN ATTRIBUTES P 48 51 align attributes p 48 and 30 and 30 AND OPEN WORLD REASONING P 14 17 28 append 35 appr
2. sor type expr not type expr atom atom atom identifier integer string 59 8 Emacs TPL Mode TPL mode for Emacs supports comfortable editing facilities for TDL grammar files It indicates matching parentheses lt gt as in Emacs LISP or TEX mode performs indentation of label lists and important for grammar development and debugging establishes a connection to the TDC system and COMMON LISP Currently the 7 D mode is implemented for ALLEGRO COMMON LISP 8 1 Installation The following installation steps let Emacs know about TPL mode 1 copy the file td1 mode el from the FDL system distribution into your Emacs load path 2 if it doesn t already exist create a directory for auto include files e g autoinclude 3 copy the file header 241 from the TDC system distribution into this directory You can modify this file but the first line should be Mode TDL 4 add the following lines to your Emacs init file emacs by default 1oad tdl mode nil t push td1 tdl mode auto mode alist 1oad autoinclude nil t push td1 header tdl auto include alist setq auto include directory autoinclude After this the header file will be included when a new file with extension tdl is created in Emacs and TDL mode will be switched on when a file s first line is Mode TDL 8 2 Key Bindings The following key bindings are defined for
3. Global variable DEFAULT AUTHOR default value possible values string This variable should contain the name of the grammar author or lexicon writer It will be used as default value for the optional keyword author in type template and instance definitions Global variable DEFAULT DOCUMENTATION default value possible values string This parameter specifies the default documentation string for type template and instance definitions It will be used as default value for the optional keyword doc in type template and instance definitions Global variable VERBOSE P default value nil possible values t or nil This parameter specifies the verbosity behavior during processing of type definitions If the value is t a verbose output will be generated If the value is ni1 only the name of the successfully defined type will be printed in brackets e g Avm lt VERB TYPE gt 5 1 Global Svvitches and Variables 29 Global variable VERBOSE READER P default value nil possible values t or nil This parameter specifies the verbosity behavior of the 7D reader If the value is nil the FDE reader does not print values that are returned from function calls and type instance template definitions Otherwise the first return value will be printed Global variable VERBOSE EXPANSION P default value nil possible values t or nil This parameter specifies the verbosity behavior when type expansion takes place If the value is
4. instance global expand control index index The first parameter in the defcontrol statement is a symbol either the name of a type or the name of an instance this depends on the surrounding environment or global which indicates global control information A defcontrol can be anywhere in a grammar file even before the corresponding type definitions A newer def control declaration with the same type and index will replace an older one this is also true for global control 5 4 2 Expanding Types and Instances expand type and expand instance The syntax is given by expand type type index index expand control expand control expand instance instance index index expand control expand control expand all types index index expand control expand control expand all instances index index expand control expand control Additional internal functions such as expand f s exist in order to destructively expand anonymous feature structure or parts of it e g from within a parser etc The index parameter may be used to define different prototypes of the same type that are possibly only partially expanded Each prototype needs its own defcontrol The indexed prototypes of a type can be spliced into a feature structure through type expansion using the expand only or expand slot of the control information Instance indices only integers are allowed can be used to define different levels
5. mbox bf 311132 lt MY DOMAIN TYPE gt set switch ATTRIB COMMAND NNnevcommand MNattrib l11 mbox sc lowercase 1 lt MY DOMAIN TYPE gt set switch TYPE COMMAND newcommand type L L1 mbox bf 1 Example Printing Huge Structures A simple way to get huge feature structures on one page is to use a small font and to hide unimportant attributes e g 50 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES count noun sem type semantics type subwff inst share var VAR Bj term type conj wff type atomic wff type INST CONTENT CON SUB WFFS 7 I aw SEM Sem PRED TYPE cw CONN semantics and TYPE rp diff list QUANT List DI pe syntax type local type SUBCAT PHRASAL TOPIC LPE head val SYN LOCAL MIN cat type MORPH HEAD SUBJ SYN PRAG SEM MAJ NON LOC Figure 4 A feature structure generated by 7 DC2IATEX lgp ethn fontsize footnotesize remove tops t label hide list SYN Example Printing Structures Hugely For slides posters etc one may choose big fonts set switch doc header documentstylela4wide times article textwidth30cm textheigth60cm lgp speaker sem fontsize LARGE Global Variables for 7DC2IATEX Most of the following global variables serve as default for the keywords in the 7DC2IATEX print functions Others are definitions for IXTgX macros for printing attr
6. 1 setlength fboxsep 0 1ex fbox corefsize coreffont 1 possible values string IATEX command for printing coreferences Global variable EMPTYNODE COMMAND default value newcommand emptynode 0 1 19 19 possible values string TATEX command for printing an empty feature structure L1 Global variable TITLE COMMAND default value newcommand featuretitle 1 centerline it 1 smallskip 5 18 Printing Feature Structures possible values string TATEX command for printing title e Global variable LATEX SIZE TRANSLATION default value tiny 0 5 scriptsize footnotesize 0 8 small normalsize 1 0 large Large 1 44 LARGE huge 2 074 Huge An assoc list for magnification factors fontsize magstep 53 0 7 0 9 1 2 1 728 2 488 54 6 TDL GRAPHER 6 TPL Grapher It is possible to display the TDC type hierarchy using the FDE grapher The FDE grapher has been implemented first in CLIM 1 2 and is now ported to CLIM 2 0 McKay et al 92 Start either type load system tdl grapher instead of load system tdl at the beginning or with the function grapher from the 77 reader An example screen dump of a TPL grapher session is shown in Figure 5 The grapher layout consists of three screen areas the menu bar with the buttons described below the grapher display and a output window with command histor
7. 5 7 Resetting Prototypes of Types and Instances 38 5 8 Accessing Internal Information Infons 38 5 9 Collecting and Printing Statistical Information 39 5 10 MemoiZation ssx Eoo ERREUR esee eae Eee 40 5 11 Tuning up Unification Training Sessions 41 5 12 Defining Reader Macros Cm nn nn nn 42 5 13 Printing Messages i s rt 2h z u makk m R UR s na E EE X ako EG 42 SAA Help ER tr Wel er 42 3 19 Walt AEG ar a AAA eludet on ORT 42 9 16 Exit FDL 5 1 fata el ea ee aA he ee 42 5 17 Getting Information about Defined Templates 42 5 18 Printing Feature Structures 2 43 5 18 1 Printing to the Interactive Screen or to Streams ASCH 43 9218 2 EEGRAMED Roh Iw Rx R SR SIR s SIR obesse ja 44 3 18 3 EDE2IATEX a an ea a ASS re Tea EE 46 6 TDL Grapher 54 7 Print Read Syntax for TDC Type Entries 56 Ti Prnt Modes PRAMAS UR 56 7 2 Global Variables EB ee SES de GE GS EG 57 3 3 BNE ta SRI LET Sq eue RS er Br ee 58 8 Emacs 7DZ Mode 59 81 Installation once s dd tra Eee dl on sw WE dd 59 6 2 KeyBindmgs sor SSS Se A AAA op obe Er we eed 59 9 Top Level Abbreviations ALLEGRO COMMON LISP Only 60 10 Sample Session 61 4 3 STARTING TDC 1 Introduction This is the secon
8. Atoms can be used as values of attributes or as disjunction elements Example The 7D type definition pi 3 phon NUMBER plural PHON en PERSON 3 1 results in the structure pl 3 phon NUMBER plural PHON en PERSON 3 An example of atoms as disjunctive elements is shown in Section 4 6 9 Atoms are not ordered hierarchically as is the case for sorts An atom only unifies with itself the top type of the type hierarchy or if defined with a built in sort of an appropriate data type i e integer atoms unify with the built in sorts integer and number the string atoms unify with the built in sort string symbolic atoms unify with the built in sort symbol These three sorts are defined in the standard built in file td1 built ins tdl Built in sorts may also be user defined One need only define an appropriate COMMON LISP type e g begin lisp DEFTYPE Even Integer AND INTEGER SATISFIES EVENP end lisp begin declare built in Even Integer end declare These lines define a COMMON LISP type Even Integer and declare it as a built in sort in TDC This sort unifies only with even integer atoms For nonmonotonic definitions see section 4 6 17 16 4 SYNTAX OFTDE 4 6 3 Paths Paths may be abbreviated using dots between attribute names e g P1 DTRS HEAD DTR CAT SYN LOCAL SUBCAT hi yields structure 5055505 4 6 4 Logical Operators In TDL values atoms types feature structures may
9. eq subsumes extends index integer for instances integer identifier string for avm types 34 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES Now we describe the expand control slots e expand function This slot specifies the basic expansion algorithm The default expansion algorithm is depth first expand with prototype memoization and a special treatment of recursive types a combination of breadth first for recursive and depth first for non recursive types The alternative is a combined types first algorithm for non recursive types and breadth first for recursive types This types first algorithm is advantageous only if feature structures with many delayed types are to be fully expanded e g at run time The behavior for recursive types is the same as with the proper depth first algorithm expand function types first expand selects the types first algorithm e delay The delay slot specifies a list of types whose expansion is deferred For each type a comparison predicate pred eq subsumes extends or user defined default is eq and a list of paths or path patterns can be defined Path patterns can facilitate path specifications denotes zero or more features one or more features exactly one feature In each case the prefix identifier can be used to define variables for features or path segments The variables are local to each path pattern identifier without a or suffix is the s
10. 10 external grapher button 55 fegramed 44 FEGRAMED 44 54 56 Fegramed grapher button 54 fgi 45 fgp 44 file only 46 filename 31 filename 45 47 FILEPATH 47 50 filepath 47 FIRST 20 21 31 FIRST IN LIST 31 fli 44 flp 44 FONTSIZEx 48 51 fontsize 48 fs n11 56 function 39 function call 22 functional constraints 22 g1b output file 41 global prototype 16 global variables 28 31 68 goto begin of tdl expression 59 goto end of tdl expression 59 grammar files 31 grapher 54 buttons 54 grapher 54 hashtable 41 header tdl 59 help 42 hide all 56 hide attribute 14 hide attributes 10 HIDE TYPES 47 52 57 hide types 56 hide types 47 hide value 14 hide values 10 IGNORE BOTTOM P 28 IGNORE GLOBAL CONTROL 32 ignore global control 33 include 30 31 41 incompatible types 14 indent line 59 region 59 index 49 infix 40 info grapher button 55 infons 38 information sharing 17 inheritance 16 multiple 17 init pos 44 inspect grapher button 55 Inspector 55 instance definition 26 delete 38 environment 26 expand 32 reset prototype 38 instances 38 intermediate 38 key bindings for Emacs TDL mode 59 keywords in definitions 25 LABEL HIDE LISTx 47 52 label hide 1ist 44 47 LABEL SORT LISTx 44 47 label sort list 44 47 INDEX LAST 21 31 LAST IN LIST 31 LAST INSTANCE 29 LAST TYPE 29 IATf
11. Ait Kaci 86 That s life Expanding append with finite input will stop of course an example of this is the last type definition in the code below 36 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES defdomain append load built ins p NIL begin domain append begin declare sort null the empty list end declare begin type avm the top avm type list null cons cons avm amp FIRST REST list Ait Kaci s version of APPEND appendO avm amp FRONT gt BACK 1 amp list WHOLE 1 appendi avm amp FRONT lt first rest1 gt BACK back amp list WHOLE lt first rest2 gt PATCH append amp FRONT resti BACK back WHOLE rest2 append appendO appendi r append FRONT lt a b gt BACK lt c d gt expand type r Full expansion of r results in the following structure r WHOLE Bla Bl Blb d c 4 append I FRONT 4 PATCH EK BACK 6 PATCH WHOLE 6 FRONT i 5 4 BACK 6 WHOLE FRONT 2 Hi BACK 6 The second way is brute force use the maxdepth slot to cut expansion at a suitable path depth The third method is to define delay patterns or to select the expand only mode The fourth method may work in some cases Prolog hackers may like it Use the attribute preference list to define the right order for expansion The last method is to define
12. Coreference Constraints 22 4 6 15 Functional Constraints 22 466 Templ te Calls 2 bot 423 3 2 LE 2 EP EHE II a 23 4 6 17 Nonmonotonicity and Value Restrictions 23 46 18 Rules 7 24 4 7 Optional Keywords in Definitions 25 4 8 Template Environment and Template Definitions 25 4 9 Instance Environment and Instance Definitions 26 4 10 Control Environment 27 4 14 isp Environment seneste mers oua A An Ms 27 ATZ Comments 22 2 15 ton STAS XS S o Vater deese e eos oS doe uS IU 2T 5 Useful Functions Switches and Variables 28 5 1 Global Switches and Variables 28 52 Setting Switches and Global Variables 31 5 3 Including Grammar Files 31 5 4 Expanding Types and Instances 32 5 4 1 Defining control information defcontrol 32 5 4 2 Expanding Types and Instances expand type and expand instance 32 5 4 3 The Syntax of expand control ooo 32 CONTENTS 3 5 4 4 Printing Control Information 35 5 4 5 Howto Stop Recursion 35 5 5 Checking VVelltypedness Appropriateness es 37 5 6 Deleting Types and Instance Definitions 38
13. Recompute and redravv the graph e g after definition of nevv types This can also be done while processing a grammar file by simply inserting the recompute statement into the file Options Menu for setting the output style e g horizontal and vertical space between nodes maximal depth etc Info Print information about the current node Other Links Toggle between showing hiding dependency arcs in the type hierarchy Toggle Autoredraw Toggle the autoredraw mode If this mode is on the graph will be redrawn automatically when a type is re defined If autoredraw mode is off which is the default the user must press the recompute bottom for an update of the graph This button toggles the value of the global variable UPDATE GRAPHER OUTPUT P see documentation on page 30 External Print information about lubs and glbs of the current node Encoding Print information about the encoding of the current node Td1 Set useful 7DE switches 56 7 PRINT READ SYNTAX FOR TD TYPE ENTRIES 7 Print Read Syntax for TDL Type Entries The output style of the print functions for TD s typed feature structures as described in section 5 18 can be controlled in a way such that different flags are printed feature are hidden or types are omitted In this section we describe the syntax of type entries mainly for the ascii printing and how the output behavior can be changed 7 1 Print Modes The type entry printer reader is configurable an
14. Richard Lamson David Linden David Moon and Ramana Rao Common Lisp Interface Manager May 1992 Pollard amp Sag 87 Carl Pollard and Ivan Sag Information Based Syntax and Semantics Vol I Fun damentals CSLI Lecture Notes Number 13 Stanford Center for the Study of Language and Information 1987 Pollard amp Sag 94 Carl Pollard and Ivan A Sag Head Driven Phrase Structure Grammar Studies in Contemporary Linguistics Chicago University of Chicago Press 1994 Rokicki 93 Tomas Rokicki DVIPS A TEX driver 1993 Documentation included in the DVIPS distri bution ftpable from most TEX sites Schafer 95 Ulrich Schafer Parametrizable Type Expansion for TPL Master s thesis Universitat des Saarlandes Department of Computer Science Saarbr cken Germany 1995 Forthcoming Smolka 88 Gert Smolka A Feature Logic with Subsorts LILOG Report 33 WT LILOG IBM Germany Stuttgart Mai 1988 Smolka 89 Gert Smolka Feature Constraint Logic for Unification Grammars IWBS Report 93 IWBS IBM Germany Stuttgart November 1989 Smolka 91 Gert Smolka Residuation and Guarded Rules for Constraint Logic Programming Research Report RR 91 13 DFKL Saarbr cken 1991 Steele 90 Guy L Steele Common Lisp The Language Bedford MA Digital Press 2nd edition 1990 Uszkoreit et al 94 Hans Uszkoreit Rolf Backofen Stephan Busemann Abdel Kader Diagne Eliza beth A Hinkelman Walter Kasper Bernd Kiefer Hans Ulrich Krie
15. TDL tdl grapher TDC Grapher system CLIM USER tdl packages package definitions CL USER tdl parse parse TDL PARSE tdl recycler TDC Recycler system TDL RECYCLER tdl simplify simplify TDL SIMPLIFY tdl statistics statistics TDL STATISTICS The TPE system depends on the systems ZEBU LALR 1 parser UD We unifier and FEGRAMED feature editor The Recycler is a tool which translates grammar files from TPLExtraLight Krieger amp Sch fer 93b into the new TDC syntax 7DC2IATEX and TPE Grapher are part of the TPL system The system is implemented in portable COMMON LISP Steele 90 and has been tested with Franz Allegro Common Lisp Macintosh Common Lisp Lucid Common Lisp and CLISP 3 Starting TDL To start TDL 1 Start COMMON LISP 2 load system td1 loads necessary parts of TDL such as the unifier YDiNe type definition reader feature editor FEGRAMED type hierarchy management and the 7 DE2TATEX interface Alter natively 1oad system tdl grapher can be used to start system td1 and the type grapher The portable system definition facility DEFSYSTEM is described in Kantrowitz 91 2Thanks to Stephan Oepen and Bernd Kiefer for checking and improving portability 3The availability of this function presupposes that the DISCO loadup environment file loadup lisp has been successfully loaded into the COMMON LISP system Refer to the DISCO installation and operation guide for details 3 After loading the
16. The input of lists can be abbreviated by using the lt gt syntax which is only syntactic sugar list it MYLIST first element fsecond gt SECOND second EMPTY lt gt 1 The resulting feature structure is list it list FIRST first element list MYLIST FIRST REST ki REST FIRST 1 es SECOND EMPTY null Dotted pair lists can be defined la LISP e g dot list DOTLIST first element second frest gt DOTREST frest 1 4 6 Type Environment and Type Definitions 21 The resulting feature structure is dot list list FIRST first element DOTLIST list REST FIRST second REST DOTREST Lists with open end can be defined by using as the last element The value of the last REST attribute will be J top In addition the lt gt notation can be combined with type and length restrictions The general syntax is x Crestriction type minlength maxlength length The following definition produces a list with element type x of length 0 1 or 2 at the top level attribute a list012 of x a lt gt x 0 2 1 cons FIRST x cons REST FIRST x A REST null cons FIRST x pos null null 4 6 12 Difference Lists Difference lists are first rest structures with distinguished attributes FIRST and REST and a special LAST attribute at the top level which shares the value with the last REST attribute Difference lists permit appendi
17. a suitable resolved predicate for a class of recursive types For further details see Sch fer 951 5 5 Checking Welltypedness Appropriateness 37 5 5 Checking Welltypedness Appropriateness TPL supports optional welltypedness checks at run time as well as at definition time The appropriateness specification for a feature is inferred by the type definition of the most general type that introduces this feature This is done by the function compute approp domain domain warn if not unique t nil Its optional keyword warn if not unique determines whether a warning is given if there is more than one most general type that introduces a feature The function is called by the two functions described below if necessary The function print approp domain domain prints the current appropriateness table of a domain This table is comparable to the Approp function in Carpenter 93 Chapter 6 But there it is defined Approp F x T 7 i e for all features and types while TPE stores Approp F gt T x T only once for each feature and infers the admissable value types by a cheap lookup at the prototypical feature structure of the sub type of the type which introduces the feature A feature structure is welltyped if each feature has an appropriate type and if the type of its value is equal to or more specific than the value type of its appropriateness specification The welltypedness check can be done 1 at definition ti
18. at definition time If t expansion will run on the prototypes with the control information known so far Global variable SIMPLIFY FS P default value t possible values t or nil If not ni1 feature structure simplification will be performed at the end of type or instance expansion Feature structure simplification may remove unnecessary fails in disjunctions and hence may speed up subsequent unifications Global variable BUILD INTERMEDIATE TYPES P default value nil possible values t or nil This global variable controls whether 7 DC introduces intermediate types for certain complex formulae recognized during the parsing of type definitions which however are not specified by the user i e these types will not occur on the left side of a type definition If the value is t intermediate types will always be created at any level of a feature structure If nil intermediate types are not created except for the top level of a type definition in order to classify the new type correctly Global variable USE INTERMEDIATE TYPES P default value t possible values t or nil This global variable controls whether intermediate types generated at definition or at run time will be 30 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES used as abbreviations during typing If nil intermediate type will not be used This variable will be used in type definitions as well as in instance definitions Global variable CREATE LEXICAL TYPES P default val
19. be combined by the logical operators conjunction unification inheritance disjunction exclusive or and negation These operators may be freely nested where has highest priority and amp binds stronger than and Parentheses may be used to break this binding or to group operands Example 1 a x amp Cb c amp r 11 Important note for Emacs users If you type in the symbol in the emacs lisp mode you must quote it with a backslash i e N Otherwise the Emacs lisp mode will wait for another closing When you are writing grammar file preferably in TPL mode of course you can omit the backslash 4 6 5 Type Specification and Inheritance All conjunctive feature structures can be given a type specification Type specification at the top level empty feature path of a type definition means inheritance from a supertype The feature definition of the specified type will be unified with the feature term to which it is attached when type expansion takes place The inheritance relation represents the definitional dependencies of types Together with multiple inheri tance described in the following section the inheritance relation can be seen as a directed acyclic graph DAG An example of type specification inside a feature structure definition follovvs agr plural type AGR person number type NUMBER plural 11 Expanding this definition results in the structure agr plural type
20. can only be applied to type infons 5 9 Collecting and Printing Statistical Information 39 e function do infon name name table table accessor st accessor function function domain domain applies a function to infon of name in table and domain Example lt MY DOMAIN TYPE gt do infon name my instance table instances accessor author e function do all infons table table accessor accessor function function domain domain applies a function to all infons in one table sorts avms templates instances in one domain Example lt MY DOMAIN TYPE gt do all infons table avms accessor surface e print all names table domain prints all names in one table in one domain it is just a special case of do all infons Example lt MY DOMAIN TEMPLATE gt print all names templates 5 9 Collecting and Printing Statistical Information The FDE system can be compiled with or without the statistics module If the system is compiled with statistics the following functions are defined e function print all statistics domain domain stream stream prints all statistical information that is available If domain is not specified this will be done for all domains e function print domain statistics domain domain stream stream prints all statistical information that are domain specific If domain is not specified the current domain is assumed e function print expand statist
21. current domain will not be changed If delete package p t is specified the corresponding package will be deleted Otherwise default only all domain specific information type definitions global hashtables etc will be deleted Example lt TDL gt deldomain MY DOMAIN lt TDL gt Definitions from the standard tdl built ins tdl file are shown below They will be included automat ically if 1oad built ins p t which is also the default is specified in defdomain begin declare built in fixnum bignum integer only COMMON LISP types can be built in atom string symbol declared as built ins sort null is the type of the empty list lt gt sort built in the top built in type sort sort the top sort type sort undef make undef a sort in order to exclude features defined on it end declare begin type avm the top avm type atom built in now specify the subtype integer lt atom 333 relation for the built ins fixnum lt integer bignum lt integer symbol lt atom 4 3 The Structure of TDZ Grammars 11 string lt atom null lt built in although null is not a real cons avm FIRST REST built in make it a subtype of list nullx cons built in diff list avm amp LIST LAST dl append avm amp LARGi LIST first difference list LAST between version of APPEND A
22. domain identifier identifier identifier print mode debug default exhaustive fs n11 hide all hide types read in td12asl x2morf filename string index integer for instances integer identifier string for avm types integer 0 1 2 3 4 5 6 7 8 9 identifier a z A Z 0 9 string gt any character 4 2 Creating and Changing Domains Domains are sets of type instance and template definitions It is possible to define and use several domains at the same time and to have definitions with the same names in different domains Domains roughly correspond to packages in COMMON LISP in fact they are implemented using the package system An arbitrary keyword symbol or string may be chosen for domain except those which are names of existing COMMON LISP packages e g TDL COMMON LISP or COMMON LISP USER All domain names will be normalized into strings containing only uppercase characters The name TDL is reserved for internal functions and variables It is possible to specify the domain of the current definition by using the begin domain domain and end domain domain block delimiters see Sections 4 3 and 4 4 10 4 SYNTAX OFTDE e function defdomain domain hide attributes attribute list hide values values list export symbols symbol list b documentation doc string top top symbol bottom bottom symbol load built ins p t ni1 errorp t ni1 creates a
23. exactly one most general type which introduces a feature TDC is not so restrictive but the warnings can be employed to write grammars that do not make use of such unacceptable appropriateness conditions Our treatment is comparable to polyfeatures in CUF D rre amp Dorna 93 38 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES PFORM PFORM TYPE TOP FEM GENDER VAL TOP MAS GENDER VAL TOP RES DL APPEND TOP ARG2 DL APPEND TOP ARG1 DL APPEND TOP 5 6 Deleting Types and Instance Definitions e function delete type type domain domain deletes a type avm or sort It removes type from the avm sort hashtable in domain domain and from the type hierarchy Example lt MY DOMAIN INSTANCE gt delete type my type e function delete instance instance domain domain index number removes instance with index number default 0 from the instance hashtable in domain domain Example lt MY DOMAIN INSTANCE gt delete instance root node index e function delete all instances domain removes all instances from the instance hashtable in domain domain default current domain Example lt MY DOMAIN INSTANCE gt delete all instances 5 7 Resetting Prototypes of Types and Instances A global prototype is a possibly partially expanded feature structure of an avm type or of an instance If a type or an instance is not expanded at all or if its definition is already fully
24. expanded then the global prototype is the same as its local one its definition or skeleton 1 e they are identical e function reset proto type domain domain index index resets the prototype of an avm type to its skeleton e function reset all protos domain resets all prototypes of all avm types in domain e function reset instance instance domain domain index number resets the prototype of an instance to its skeleton e function reset all instances domain resets the prototypes of all instances in domain 5 8 Accessing Internal Information Infons The following functions apply a functional argument function a COMMON LISP function e g a print function collector etc to the slots of the internal representation infon structures of avms sorts instances and templates domain specifies the domain default current domain name must be the name of a sort avm template or instance table may be one of avms the default sorts templates instances accessor may be one of the following slot accessor functions name the default surface domain intermediate comment author date value types restriction types atomic symbols at tributes expand control skeleton prototype creation index monotonic overwrite values overwrite paths There is an additional accessor function parameters which can be applied only to template infons The additional accessors class info and mixed
25. following optional keywords e remove tops flag default value nil possible values tlnil If flag is t attributes with empty values 1 e values that unify with everything i e the top type of the 44 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES hierarchy will not be printed If flag is nil all attributes except those in label hide list will be printed e label hide list identifier default value possible values a list of symbols attribute names Attributes in the list and their values will not be printed label sort list identifier default value the value of LABEL SORT LIST possible values a list of symbols attribute names the list defines an order for attributes to be printed Attributes of the feature structure will be printed first to last according to their left to right position in the list All remaining attributes which are not member of the list will be printed at the end e stream stream default value t possible values t nil a COMMON LISP stream If stream is t the feature structure will be printed to standard output or to the interactive screen If stream is nil the feature structure will be printed to a string In all other cases the feature structure will be printed to the LISP stream stream e init pos number default value 0 possible values a positive integer number number defines the left margin offset space characters for the feature structure to be printed e re
26. name type If no type name is specified plp prints the prototype of the ast type defined before evaluating plp The local prototype or skeleton contains only the ocal information given in the definition of type Example lt MY DOMAIN TYPE gt plp mas sg agr init pos 12 hide types T GENDER FEM MAS 41 NUH SG e function pgp type print option pgp prints the global prototype of the feature structure with name type If no type name is specified pgp prints the prototype of the last type defined before evaluating pgp The global prototype contains all information that has been inferred for type type by type expansion so far Example lt MY DOMAIN TYPE gt pgp mas sg agr TYPE MAS SG AGR GENDER GENDER VAL FEM MAS 41 CASE NUM SG e function pli instance print option pli prints the local prototype of the instance with name instance If no instance name is specified pli prints the prototype of the last instance defined before evaluating pli The local prototype or skeleton contains only the local information given in the definition of instance e function pgi instance print option pgi prints the global prototype of the instance with name instance If no instance name is specified pgi prints the prototype of the ast instance defined before evaluating pgi The global prototype contains all information that has been inferred for instance by expansion so far print options are the
27. new domain domain a symbol or a string Options values list is a list of attributes whose values will be hidden at definition time attribute listis a list of attributes that will be hidden including their values at definition time symbol list is a list of symbols to be exported from the domain package These three symbol lists can also be declared in the declare part cf Section 4 5 If load built ins p t is specified the standard file of TDE built in types will be included otherwise nothing will be loaded The default is t top and bottom define the name of the top and bottom symbol the default is the value of the global variables TOP SYMBOL and BOTTOM SYMBOL A domain can be given documentation using the documentation keyword its value must be a string If errorp t is specified it will cause error to redefine a domain If the value of errorpis nil default only a warning will be given Example lt TDL gt defdomain MY DOMAIN load built ins p nil lt DOMAIN MY DOMAIN gt lt TDL gt e function deldomain domain errorp t ni1 delete package p t ni1 deletes domain domain symbol or string which includes all type instance and template definition as well as the corresponding package with package name domain including all symbols defined in this package If errorp t is specified using an undefined domain name will cause an error If errorp nil is specified default a warning will be given and the
28. pes MDCT ORE AGR 1 PERSON plural 1 Novv an example of type inheritance at the top level pl type person number type NUMBER plural 1 Expanding this definition results in the structure pl type PERSON L1 NUMBER plural This feature structure is called the global prototype of pl type an expanded feature structure of a defined type which has possibly inherited information from its supertype s is called a global prototype A feature 4 6 Type Environment and Type Definitions 17 structure consisting only of the local information given by the type definition is called a local prototype or skeleton So the local prototype of pl type is person number type NUMBER plural Section 5 18 explains how the different prototypes of a defined type can be displayed As mentioned above type specification is optional If no type is specified the structure being defined will be assumed to have the top type of the hierarchy 4 6 6 Multiple Inheritance Multiple inheritance is possible at any level A glb greatest lower bound type is not required to exist if the global variable AND OPEN WORLD REASONING P has value t Suppose number type person type and gender type are defined as follows number type NUMBER person type PERSON gender type GENDER Then the FDE type definition mas 2 type number type amp person type amp gender type amp GENDER mas PERSON 2 1 would result in
29. 9 print all names 39 print all statistics 30 print approp 37 PRINT CATEGORY LIST 56 57 print control 5 35 print domain statistics 39 print expand statistics 39 print global statistics 39 PRINT NEWLINE 57 PRINT ONLY NON DEFAULTS 56 57 PRINT PROFILE LIST 56 print recursive sccs 35 print simplify memo tables 40 print simplify statistics 39 PRINT SLOT LENGTH 57 PRINT SLOT LIST 56 57 PRINT SORTS AS ATOMS 56 57 print switch 5 31 69 PRINT TITLE P 49 5 print title p 49 print unified types 41 PRINT VAR STACK 56 prototype global 16 local 16 prototype 38 read in 56 read in 44 read in mode 44 recompute 55 recompute grapher button 55 REMOVE TOPS 47 52 remove tops 43 47 reset prototypes 38 reset grapher button 55 reset all instances 38 reset all protos 38 reset all statistics 39 reset domain statistics 39 reset expand statistics 39 reset global statistics 39 reset instance 38 reset proto 38 reset simplify statistics 39 RESOLVED PREDICATEx 32 resolved predicate 33 REST 20 21 31 REST IN LIST 31 restore print mode 56 restriction 57 restriction 23 restriction types 38 RETURN FAIL IF NOT WELLTYPED P 37 rule inheritance 24 rules 24 sample session 61 save print mode 56 save simplify memo table 40 semicolon 27 set print mode 56 set switch 5 31 setting switches 31 xSHELL COMMAND s 47 51 shell command 47 SIGNAL BOTTOM P 28 simpl
30. D rre Disjunctive Unification WBS Report 124 IWBS IBM Germany Stuttgart 1990 Fra 92 Allegro CL User Guide Technical report Berkeley CA March 1992 2 volumes Goossens et al 94 Michel Goossens Frank Mittelbach and Alexander Samarin The LATEX Companion Reading MA Addison Wesley 1994 Jameson et al 94 Anthony Jameson Bernhard Kipper Alassane Ndiaye Ralph Sch fer Joep Simons Thomas Weis and Detlev Zimmermann Cooperating to be Noncooperative The Dialog System PRACMA Technical report Universit t des Saarlandes SFB 314 KI Wissensbasierte Systeme Saarbr cken Germany 1994 Kantrowitz 911 Mark Kantrowitz Portable Utilities for Common Lisp Technical Report CMU CS 91 143 School of Computer Science Carnegie Mellon University Pittsburgh PA 1991 Kiefer amp Fettig 94 Bernd Kiefer and Thomas Fettig FEGRAMED An Interactive Graphics Editor for Feature Structures Technical report Deutsches Forschungszentrum f r K nstliche Intelligenz Saarbr cken Germany 1994 Forthcoming Krieger amp Sch fer 93a Hans Ulrich Krieger and Ulrich Sch fer TDL A Type Description Language for Unification Based Grammars In Proceedings Neuere Entwicklungen der deklarativen KI Programmierung pp 67 82 Saarbr cken Germany September 1993 Deutsches Forschungszen trum f r K nstliche Intelligenz DFKI Research Report RR 93 35 Krieger amp Sch fer 93b Hans Ulrich Krieger and Ulrich Sch fer TDL
31. Deutsches i orschungszentrum f r K nstliche Docume nt Intelligenz GmbH D 94 14 TDL A Type Description Language for HPSG Part 2 User Guide Hans Ulrich Krieger Ulrich Sch fer December 1994 Deutsches Forschungszentrum f r K nstliche Intelligenz GmbH Postfach 20 80 Stuhlsatzenhausweg 3 67608 Kaiserslautern FRG 66123 Saarbr cken FRG Tel 49 631 205 3211 Tel 49 681 302 5252 Fax 49 631 205 3210 Fax 49 681 302 5341 Deutsches Forschungszentrum f r K nstliche Intelligenz The German Research Center for Artificial Intelligence Deutsches Forschungszentrum f r K nst liche Intelligenz DFKI with sites in Kaiserslautern and Saarbr cken is a non profit organization which was founded in 1988 The shareholder companies are Atlas Elektronik Daimler Benz Fraunhofer Gesellschaft GMD IBM Insiders Mannesmann Kienzle Sema Group Siemens and Siemens Nixdorf Research projects conducted at the DFKI are funded by the German Ministry for Research and Technology by the shareholder companies or by other industrial contracts The DFKI conducts application oriented basic research in the field of artificial intelligence and other related subfields of computer science The overall goal is to construct systems with technical knowledge and common sense which by using Al methods implement a problem solution for a selected application area Currently there are the following research areas at the DFKI O Int
32. E P 28 VERBOSE READER P 29 VERBOSE WELLTYPEDNESS CHECK P 37 WAIT 48 52 wait 46 48 wait 42 WARN IF REDEFINE TYPEx 28 WARN IF TYPE DOES NOT EXIST 28 WARN NORMAL FORM P 30 WARN UNIFICATION P 30 welltypedness 37 where 22 WHICH PARSER 25 vith print mode 5 56 x2morf 56 REFERENCES 71 References Ait Kaci amp Nasr 86 Hassan Aft Kaci and Roger Nasr Residuation A Paradigm for Integrating Logic and Functional Programming Technical Report AI 359 86 MCC Austin TX 1986 Ait Kaci 86 Hassan Ait Kaci An Algebraic Semantics Approach to the Effective Resolution of Type Equations Theoretical Computer Science 45 293 351 1986 Backofen amp Weyers 95 Rolf Backofen and Christoph Weyers UDiNe A Feature Constraint Solver with Distributed Disjunction and Classical Negation Technical report Deutsches Forschungszentrum f r K nstliche Intelligenz Saarbr cken Germany 1995 Forthcoming Carpenter 93 Bob Carpenter The Logic of Typed Feature Structures Tracts in Theoretical Computer Science Cambridge Cambridge University Press 1993 D rre amp Dorna 93 Jochen D rre and Michael Dorna CUF A Formalism for Linguistic Knowledge Representation In Jochen D rre ed Computational Aspects of Constraint Based Linguistic Description I pp 1 22 ILLC Department of Philosophy University of Amsterdam 1993 DYANA 2 Deliverable R1 2 A Eisele amp D rre 90 Andreas Eisele and Jochen
33. ED fegramed options are the following optional keywords e filename filename default value type gpi fed type 1p fed instance lii fed or instance gii fed possible values a string or a LISP path name Unless filename is specified a filename will be computed from the type or instance name and the index i of the instance or the global prototype The file will be created by the 7D FEGRAMED interface in order to communicate the feature structure information 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES e wait flag default value nil possible values tlnil If flag is t FEGRAMED will wait until the user chooses the return options If flag is nil FEGRAMED will not wait e file only flag default value nil possible values tlnil If flag is t the FEGRAMED interface function will only generate an output file but not execute the FEGRAMED program on it If flag is nil the file will be generated and FEGRAMED will be called Further details are described in Kiefer amp Fettig 94 An example screen dump of a feature structure in FEGRAMED is shown in Figure 3 5 18 3 TDL2I8TEX TDL2IATEX is a tool which generates TATEX compatible high quality output of TPL feature structure types Lamport 86 Goossens et al 941 7T DC Interface Functions to TDL2IATEX e function 11p type latex option 11p starts TDL2IATEX with the local prototype skeleton of the feature structure with name type If no type name is specifie
34. Example defcontrol global attribute preference first rest last head dtr comp dtrs front back e ask disj preference If this flag is set to t the expansion algorithm interactively asks for the order in which disjunction alternatives should be expanded Example 5 4 Expanding Types and Instances 35 Ask Disj Preference in G under path X The following disjunctions are unexpanded Alternative 1 Type A Expanded NIL Alternative 2 Type B Expanded NIL Which alternative in G under path X should be expanded next 1 2 or O to leave them unexpanded or all to expand all alternatives in this order or quiet to continue without asking again in G _ e use conj heuristics and use disj heuristics Uszkoreit 91 suggested that exploitation of numerical preference information for features and disjunctions would speed up unification These slots control the use of this information in conjunctive and disjunctive structures respectively e resolved predicate This slot specifies a user definable predicate that may be used to stop recursion The description of such predicates is be rather complex and is omitted here The default predicate is alvays false which will make the expansion algorithm complete if no delay or maxdepth restriction is given of course e ignore global control If this flag has value t the values of the three globally specified lists expand only expand delay will be ignored If ni1 loca
35. ExtraLight User s Guide Technical report Deutsches Forschungszentrum f r K nstliche Intelligenz Saarbr cken Germany 1993 DFKI Document D 93 09 Krieger amp Sch fer 94a Hans Ulrich Krieger and Ulrich Sch fer TDL A Type Description Language for HPSG Part 1 Overview Technical report Deutsches Forschungszentrum f r K nstliche Intelligenz Saarbr cken Germany 1994 DFKI Research Report RR 94 37 Krieger amp Sch fer 94b Hans Ulrich Krieger and Ulrich Sch fer 7 DC A Type Description Language for Constraint Based Grammars In Proceedings of the 157 International Conference on Compu tational Linguistics COLING pp 893 899 Kyoto Japan 1994 Krieger 93 Hans Ulrich Krieger Single Link Overwriting A Conservative Non Monotonic Extension of Unification Based Inheritance Networks Technical report Deutsches Forschungszentrum f r K nstliche Intelligenz Saarbr cken Germany 1993 Draft version 72 REFERENCES Krieger 95 Hans Ulrich Krieger 7DC A Type Description Language for Constraint Based Grammars Foundations Implementation and Applications PhD thesis Universit t des Saarlandes Depart ment of Computer Science Saarbr cken Germany 1995 Forthcoming Lamport 86 Leslie Lamport IATEX User s Guide amp Reference Manual A document preparation system Reading Massachusetts Addison Wesley 1986 McKay et al 92 Scott McKay William York John Aspinall Dennis Doughty Charles Hornig
36. LISP code the following prompt appears on the screen Welcome to the Type Description Language TDL USER 2 _ 4 The 7 DC reader is invoked by simply typing td1 You can either work interactively e g create a domain define types etc or load TD grammar files by using the include command If an error has occurred e g a syntax error 641 restarts the TDC reader 5 1dt exits the TD reader and returns to COMMON LISP The COMMON LISP function EXIT quits the interpreter If you are in an Emacs environment C x C c kills the Emacs process It is also possible to define one s own portable system definitions in the Kantrowitz 91 paradigm which could then automatically start TPE and include grammar definitions etc 4 Syntax of 7 D The FDE syntax provides type definitions instance definitions for rules and lexicon entries templates parameterized macros specification of declarative control information as well as statements calls to built in functions that are especially useful for the interactive development of NL grammars There is no difference between the syntax of TDC grammar files and the syntax for the interactive mode All syntactic constructs can be used in either mode Note that the arguments of statements need to be quoted if they are symbols or lists containing symbols This is necessary if the statement is defined as a COMMON LISP function but not if the statement is defined as a COMMON LISP macro Almost a
37. RG2 LIST between LAST last RES LIST amp first LAST last rule the most general rule type use instead of top because top status RULE is only the default top symbol which unary rule can be overwritten through DEFDOMAIN rulet gt stop lt top gt binary rule moreover use the status keyword to rule gt gt let Bernie s parser know about the ternary rule the special role of rule xrulek gt lt 1 E gt end type 4 3 The Structure of TDL Grammars A TDC grammar may consist of type definitions sort declarations template definitions instance specifica tions and control information In addition it is possible to mix different domains and LISP code The structuring feature in TD grammars is the begin and end statement which is comparable to BE GIN END blocks in PASCAL or the TATEX environments Environments determine syntactic as well as semantic contexts for different purposes Some environments provide the necessary preconditions for enclosed definitions e g the domain environ ment supports definitions of entire type lattices the necessary context for type definitions Others such as the control environment are completely optional Another constraint is that template definitions precede the type or instance definitions that contain template calls cf macros in programming languages Environments c
38. X printing feature structures with 46 TEX grapher button 54 latex fs 46 LATEX HEADER P 48 51 latex header p 48 49 LATEX SIZE TRANSLATION 53 ldt 42 leval 5 27 lexical rules 24 lgi 46 LISP 27 lisp environment 27 LIST 31 LIST 31 list 20 difference 21 dotted pair 20 empty 20 end of 20 with open end 21 with restrictions 21 LIST IN LIST 31 LIST TYPE SYMBOL 31 11i 46 11 46 LOAD BUILT INS Px 30 load built ins p 10 30 load simplify memo table 40 41 local prototype 16 logical operators 16 MATHMODE 49 51 mathmode 49 MAXDEPTH 32 maxdepth 33 memo output file 4l memoization 40 message 42 metasymbols in BNF 5 mixed 38 monotonic 38 multiple inheritance 17 name 39 name 38 negated coreferences 18 negation 22 nil 14 nonmonotonicity 23 NORMALFORM OPERATOR SYMBOL 30 INDEX not 22 NULL 31 number 15 operators logical 16 optional keyvvords 25 options grapher button 55 or 30 other links grapher button 55 overwrite paths 38 overwrite values 38 overwriting 23 parameters 38 pathname 31 paths 16 pgi 43 pgp 43 pli 43 plp 43 POSTER 49 51 poster 49 PostScript 47 50 55 PPRINT LISTS 49 51 pprint lists 49 prefix 49 print feature structures to text files 43 to the screen 43 with FEGRAMED 44 with TATPX 46 print graph grapher button 55 print messages 42 print modes 56 print statistics 3
39. able application would be lexical types that normally will not be unified with a nonmonotonically defined lexicon entry Note that the L 1 syntax denotes a set of overwrite paths with associated overwrite values This is different from the 1 notation known from avm type or instance definitions because everything following a path specification identifier identifier is the overwrite value and will replace all inherited information at this path begin type a person x integer person y integer b a amp person x 1 2 person y 1 2 c b amp person x 3 d b person x three 1 error restriction violated end type The expanded prototype of c is c PERSON X 3 1 PERSON Y 2 24 4 SYNTAX OFTDE If TDL has been compiled with the TDL Restriction compiler option the restriction type specifi cation at attributes will be checked before paths are overwitten If an overwrite value is not equal to or more specialized than the type specified in the definition of the structure to be overwritten an error will be signaled Error Restriction INTEGER is inconsistent with overwrite value ATOM three under path PERSON X in D Restart actions select using continue 0 Continue overwrite restriction anyway 4 6 18 Rules Different parsers use different representations for rules The gt syntax allows abstraction from the internal representation of rules as feature structure
40. ad in mode flag default value nil possible values t nil If t the feature structure is printed in a way such that the output could be used by UDiNe s input function build fs Otherwise a pretty print is done To be read in feature structures have to be printed with print mode read in see section 7 Otherwise type information may be incomplete 5 18 2 FEGRAMED FEGRAMED is a feature structure editor Kiefer amp Fettig 94 It can be started from TPE through the function fegramed Feature structures from DC can be passed to FEGRAMED using the following commands e function flp type fegramed option flp starts FEGRAMED with the local prototype of the feature structure with name type If no type name is specified flp takes the prototype of the last type defined before evaluating flp The local prototype or skeleton contains only the ocal information given in the definition of type type Example lt MY DOMAIN TYPE gt flp mytype e function fgp type fegramed option fgp starts FEGRAMED with the global prototype of the feature structure with name type If no type name is specified fgp takes the prototype of the last type defined before evaluating fgp The global prototype contains all information that has been inferred for type type by type expansion so far Example lt MY DOMAIN TYPE gt fgp mas sg agr wait t hide types t e function fli instance fegramed option fli starts FEGRAMED with the oc
41. al prototype of instance instance If no instance name is specified fli takes the prototype of the last instance defined before evaluating fli The local prototype or skeleton contains only the local information given in the definition of instance Example lt MY DOMAIN INSTANCE gt fli agr en type 5 18 Printing Feature Structures 45 e function fgi instance fegramed option 1 fgi starts FEGRAMED with the global prototype of instance instance If no instance name is specified fgi takes the prototype of the last instance defined before evaluating fgi The global prototype contains all information that has been inferred for instance instance by expansion so far e home cl home schaefer tmp verb agr type gp fed Structures Edit Find Options bu DFKI VERB AGR T YPE A SYN SYNTAX T YPE LOCAL LOCAL T YPE HEAD VHEAD T YPE FIN FIN V AL A R VAGR VAL NUM Bree PERS error MOOD TOP TENSE INF NIL Ni Vie MIN TOP MOD TOP SUB DP NOM TYPE SYN TSYNTAX TYPE LOCAL NON LPE TYPE HEAD DHEAD TYPE INFL GRADE Fee AGR nom CASE NOM VAL Gov OBL GENDER s roe NUM 7 0r GRADE ST PERS error NCAT TYPE Nit vi MIN FCOMPL T YPE MOD TOP SUBJ LPE SUBCAT NULE SUBJ SC NIL V SUBCAT NIL SUBCAT TOP Figure 3 A feature structure type in FEGRAM
42. ame the all keyword can be specified to count all nodes in all instances or types with index In this case verbose t will output the number of nodes for each type or instance Otherwise only the total will be printed E b b b b E The filename or stream argument can be used to redirect the output to a file or a stream default standard output expand p t will expand structures before counting if necessary default is nil When called from Lisp the function returns 9 values integers in the order as below Here is an example output Total number of nodes in all instances of conj avm nodes 13868 of atomic nodes 5564 of sortal nodes 3697 of attributes 24717 of disj nodes 644 of disj elements 1606 of fail nodes 0 of undef nodes 0 of shared nodes 2763 total of nodes 23773 If domain is not specified the current domain is assumed 5 10 Memoization At definition time as well as at run time type expressions are simplified syntactically and semantically and stored in memoization hashtables In each domain there are four memo tables for conjunctive and disjunctive normal form and with and without exploiting information from the type hierarchy e function clear simplify memo tables domain domain threshold integer clears the simplification memo tables If the threshold number is specified only entries that have been used less than or equal to integer times will be removed
43. ame as identifier i e one feature variable Example defcontrol mytype delay vtype syn loc sem x head x ntype subsumes index 42 Here expansion of the type vtype will be delayed under all paths which start with syn loc and all paths which start with sem then an arbitrary feature bound to variable x then head then the second feature again constraint by variable x Expansion of the type ntype and all its subtypes will be delayed under all paths e expand only and expand There are two mutually exclusive type expansion modes If the expand on1y list is specified only types in this list will be expanded all others will be delayed If the expand listis specified all types will be expanded Types not mentioned in the list will be expanded using the default prototype index nil i e fully if not specified otherwise In both cases the types in the delay list will be delayed anyway index specifies the index of the prototype to be spliced in pred is as described in the paragraph before delay e maxdepth If maxdepth integer is specified all types at paths longer than integer will be delayed anyway This feature may be used as a brute force method to stop infinite expansion e attribute preference This slot defines a partial order on attributes The sub feature structures at the leftmost attributes will be expanded first This may speed up expansion if no numerical preference data is available
44. an be nested freely the so called environment stack keeps track of this and distributed over different grammar files The loading of files may also be nested cf the include documentation The TDL prompt indicates the current domain and the current environment Its general output format is domain environment e g lt MY DOMAIN TEMPLATE gt _ If no domain is active the prompt is lt TDL gt Typically a 7DC grammar starts with the definition of a domain defdomain changes to this domain begin domain declares sorts begin end declare defines templates begin end template feature types begin end type and finally instances begin end instance Example Ihe structure of tdl grammars n example defdomain grammar this includes a default initial type hierarchy defdomain junk domain load built ins p NIL set switch verbose p nil set verbosity begin template TERNARY RULE BINARY RULE RULE UNARY RULE LIST AVM SORT UNDEF BUILT IN Figure 1 The initial type hierarchy with begin domain grammar we start with semantics begin declare include grammar semantic sorts 4 SYNTAX OF TPL NULL STRING ATOM SYMBOL BIGNUM INTEGER FIXNUM load built ins p t sorts organism moveable nonmoveable physical selfmoving nonselfmoving animated non animated vehicle sign word phrase end declare include grammar semantic templa
45. attributes p flag default value value of ALIGN ATTRIBUTES P nil possible values t nil If flag is t attribute names and values will be aligned If flag is ni1 no alignment will take place fontsize size default value value of 512 normalsize possible values a string This parameter sets the size of the 12 feature structures It must be a string consisting of a valid IATEX font size name e g tiny scriptsize footnotesize small normalsize large Large LARGE huge or Huge corefsize size default value value of variable COREFSIZE nil possible values nil string This parameter sets the font size for coreference symbols If size is nil the size for the coreference symbol font will be computed from the value of the fontsize keyword A font one magnification step smaller than given in fontsize will be taken If size is a string it must contain a valid LATEX font size as in fontsize coreffont string default value value of variable COREFFONT rm This parameter sets the IATEX font name for printing coreference symbols string must contain a valid IATEX or user defined font name e g tt bf it etc coreftable a list default value value of variable COREFTABLE This parameter defines a translation table for coreferences and corresponding full names strings or numbers e g 1 subcat 2 phon 3 1 4 2 Allcoreference numbers at the left side of eac
46. bal Variables 57 PRINT SLOT LIST PRINT CATEGORY LIST RM debug sort p expanded delta avms sorts atoms default expanded avms sorts atoms exhaustive sort p delta restriction expanded avms sorts atoms tdl2asl avms sorts atoms fs nll avms sorts atoms hide all 0 hide types atoms read in sort p delta restriction expanded avms sorts atoms x2morf expanded sort p sorts atoms 7 2 Global Variables The following global variables are defined in package TDL e PRINT SLOT LIST default value sort p expanded possible values list of complete delta expanded restriction sort p used in ascii printing 7DC2IATEX FEGRAMED type slots to be printed The type slot is always printed e PRINT CATEGORY LIST default value atoms avms sorts possible values list of atoms avms sorts used in ascii printing FEGRAMED List of tdl type categories to be printed PRINT ONLY NON DEFAULTS default value t possible values t nil used in ascii printing 7DC2IATEX FEGRAMED If nil all slots in PRINT SLOT LIST are printed If not nil only slots with non default values that are member of PRINT SLOT LIST are printed The default values are complete t delta nil expanded t restriction TOP sort p nil If PRINT ONLY NON DEFAULTS is t and these 4 slots have default value and type value is the top type of the current domain then no type e
47. bsumes extends 4 1 3 Instance Definitions instance def instance avm def instance identifier 4 1 4 Template Definitions template def templ name templ par 1 templ par body 1 option 4 1 5 Declarations declaration partition incompatible sort def built in def hide attributes hide values export symbols partition type type 4 type incompatible gt nil type amp type sort def sort s type 1 type built in def built in s type type hide attributes gt hide attributels identifier 1 identifier hide values hide value s identifier 1 identifier export symbols export symbol s identifier 1 identifier 8 4 SYNTAX OF TPL 4 1 6 Statements statement check welltypedness type instance all instances avms domain domain indexindex verbose t n 1 clear simplify memo tables domain domain threshold integer compute appropl domain domain warn if not unique t 1311 defcontrol global type instance expand control index index defdomain domain defdomain option deldomain domain defreadermacro identifier string nil string delete all instances domain delete instance instance domain domain index integer delete type type domain domain describe template fempl name domain do all infons infon
48. come the specified one If no status option is given the status will be inherited from the top level types The values of author doc and date must be strings The default value of author is defined in the global variable DEFAULT AUTHOR The default value of doc is defined in the global variable DEFAULT DOCUMENTATION see Section 5 The default of date is the current time and date 4 10 Control Environment A control environment starts with begin control and ends with end control It may appear anywhere within a domain environment and must be enclosed directly by either an instance or a type environment It may contain arbitrary control definitions other environments and TDC statements The control environment is supported only for the sake of clarity in order to structure a TDL grammar The environment itself is completely syntactic sugar Control information can be given either in a type or instance definition by the optional expand control keyword or through the def control statement in a type or instance environment The control environment additionally allows specification of control information separately from the type or instance definitions e g in a separate file Note that the control environment needs to be enclosed by a domain environment and either a type or an instance environment depending on what kind of definitions are to be expanded The macro defcontrol type instance global expand control ind
49. cons type Global variable DIFF LIST TYPE SYMBOL default value DIFF LIST possible values a symbol This variable contains the name for the difference list type Global variable END OF LIST default value NULL possible values a symbol This variable contains the name for the end of list type sort Global variable FIRST IN LIST default value FIRST possible values a symbol This variable contains the name for the FIRST attribute in first rest lists Global variable REST IN LIST default value REST possible values a symbol This variable contains the name for the REST attribute in first rest lists Global variable LAST IN LIST default value LAST possible values a symbol This variable contains the name for the LAST attribute in difference lists Global variable LIST IN LIST default value LIST possible values a symbol This variable contains the name for the LIST attribute in difference lists 5 2 Setting Switches and Global Variables e macro set switch identifier Common Lisp Expression This macro sets the value of a global value with name identifier cf Section 5 1 Example lt MY DOMAIN TYPE gt set switch WARN IF TYPE DOES NOT EXIST NIL e function print switch identifier This function prints the value of a global variable Example lt MY DOMAIN TYPE gt print switch AUTHOR 5 3 Including Grammar Files The function include filename includes FD grammar files If no begin domain is specifie
50. coref name coref name 1 coref name coref name identifier integer distributed disi gt Ydisj name disjunction 1 disjunction disj name identifier integer templ call Gtempl name templ par templ par templ name identifier templ par templ var disjunction templ var identifier integer constraint coref name function call disjunction function call function name disjunction 1 disjunction function name identifier nonmonotonic type amp overwrite path I overwrite path 1 overwrite path identifier I identifier disjunction subtype def 1 type 1 option option gt status identifier author string date string doc string expand control expand control 4 1 TDE BNF expand control C expand type type index pred path gt expand only type type index pred path delay 1 ope type pred path V 2 maxdepth integer ask disj preference t nil attribute preference identifier use conj heuristics t nil use disj heuristics t nil expand function depth types first expand resolved predicate resolved p always false C ignore global control t nil path identifier pattern identifier pattern pattern gt identifier pred eq su
51. d Global variable TITLE default value nil possible values nil or string If string title of feature structure If nil no title will be printed Global variable WAIT default value nil possible values t or nil If t T DC2IATEX will wait for shell command to be terminated if nil 7DC2IATEX will not wait Global variable LABEL HIDE LIST default value possible values list of symbols List of attribute symbols to be hidden Global variable HIDE TYPES default value nil possible values t or nil If nil types will be printed if t types will be hidden Global variable ARRAYCOLSEP default value 0 3ex possible values string Distance a 12 length value between braces resp brackets and attribute names and their values Global variable ARRAYSTRETCH default value 1 1 possible values number factor for distance between attributes in conjunctions or values in disjunctions Global variable ATOM COMMAND default value newcommand atom 1 mbox tt 1 possible values string ATEX command for printing atoms Global variable ATTRIB COMMAND default value newcommand attrib 1 mbox tt HINN possible values string IATFX command for printing attribute names Global variable TYPE COMMAND default value NNneucommand NNGype 1 mbox it 1 possible values string IAIgX command for printing types Global variable COREF COMMAND default value newcommand coref
52. d 11p takes the prototype of the ast type used before evaluating 11p The ocal prototype LP contains only the ocal information given in the definition of type type Example lt MY DOMAIN TYPE gt 11p agr en type fontsize small doc header documentstyle a4 times article function 1gp type latex option 1gp starts TDL2IATEX with the global prototype of the feature structure with name type If no type name is specified 1gp takes the prototype of the last type used before evaluating 1gp The global prototype GP contains a information that has been inferred for type type by type expansion so far Example lt MY DOMAIN TYPE gt lgp agr en type mathmode equation function 11i instance latex option function 1gi instance latex option 11i and 1gi start TDL214TpX with the feature structure of instance instance The local instances LD contain only the ocal information given in the definition of instance skeleton The global instances GI contain a information that has been inferred for instance instance by expansion so far Example lt MY DOMAIN INSTANCE gt lli head initial rule index 0 lt MY DOMAIN INSTANCE gt lgi head initial rule index 0 The optional keywords latex options are described in section 5 18 3 There is also a function latex fs which operates on feature structures analogously to UDiNe s print fs It roughly takes the same arguments as 1gp etc An example of a comple
53. d at the beginning of the file the definitions are loaded in the current domain include files may be arbitrarily nested filename should be a string containing a filename or a path If no absolute filename path is specified the default path of variable SOURCE GRAMMAR is taken TDL filenames must have the 641 extension If no such extension is specified it will be appended automatically Example lt MY DOMAIN DECLARE gt include my declarations is equivalent to lt MY DOMAIN DECLARE gt include my declarations tdl 32 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES 5 4 Expanding Types and Instances Type expansion means replacing the type names in typed feature structures by their definitions Partial expansion can be done according to the control information given by the defcontrol statements or the expand control keywords Default is full expansion of all types All expand functions store the expanded structures in the global prototype slot of the type or instance infon cf Section 5 8 The local prototype skeleton always remains unchanged 5 4 1 Defining control information defcontrol The control information for the expansion algorithm may be specified globally and or locally either in a separate file or mixed with the type and instance definitions The begin control end control environment can be used to indicate control information but this is not necessary The syntax of macro defcontrolis defcontrol type
54. d part of TD A type description language for HPSG This documentation serves as a user guide to FPL It is intended as a guide for grammar writers rather than as a comprehensive internal documentation Some familiarity with grammar formalisms theories such as Head Driven Phrase Structure Grammar Pollard amp Sag 87 Pollard amp Sag 94 is assumed The manual describes the syntax of the TPL formalism the user accessible control functions and variables and the various tools such as type grapher feature editor 7 DE2TATEX Emacs TDL mode and print interface For motivation architecture properties of the type hierarchy implementational issues and comparison to related systems refer to Krieger amp Sch fer 93a Krieger amp Sch fer 94a Krieger amp Sch fer 94b Krieger 95 and Sch fer 95 The system is integrated into various natural language systems such as DISCO Uszkoreit et al 94 and PRACMA Jameson et al 94 Corrections and other information can be ftp d from ftp c1 ftp dfki uni sb de pub tdl World Wide Web publications software etc http cl www dfki uni sb de Email td10dfki uni sb de 2 7DL System The FDE distribution includes COMMON LISP source files in the following directories which correspond to the modules of the system definition td1 compile compile TDL COMPILE tdl control control TDL tdl elisp Emacs lisp files td1 encode hierarchy TDL HIERARCHY tdl expand expand
55. d supports different modes print modes for dumping trans forming typed feature structures to files or other modules of a NL system The easiest way to change the print mode is to use the following functions macros e Macro with print mode mode lisp body Temporarily sets print mode to mode and executes lisp body e Function save print mode Saves print mode to stack PRINT VAR STACK e Function restore print mode Restores print mode from stack PRINT VAR STACK e Function set print mode mode Sets print mode mode Default for mode is default The default global print mode is default it may be changed by the user for debugging purposes etc Possible modes are debug default exhaustive fs nll hide all hide types read in tdl2asl x2morf Additional user modes can be defined by extending the global variable PRINT PROFILE LIST Examples Save Print Mode saves print mode Set Print Mode debug changes print mode debugging Restore Print Mode restores print mode With Print Mode X2MORF print fs calls can be used in the X2MORF grammar dumping function With Print Mode FS NLL print fs calls for FS to NLL translations The print mode functions macro change the following four global variables e PRINT SLOT LIST e PRINT CATEGORY LIST e PRINT SORTS AS ATOMS in the table below column 4 e PRINT ONLY NON DEFAULTS x in the table below column 5 7 2 Glo
56. der and returns to COMMON LISP 5 17 Getting Information about Defined Templates function describe template femplate name prints a short information text about a template definition Example 5 18 Printing Feature Structures 43 MY DOMAIN TEMPLATE describe template a template The template A TEMPLATE has the folloving definition a template inherit TOPx attrib PHON value inherit amp attrib 1 amp value COPY 1 The template A TEMPLATE has been defined on 03 15 1994 at 17 12 23 The author is tdl info The following documentation is associated with A TEMPLATE 5 18 Printing Feature Structures For debugging and documentation purposes it is possible to print prototypes of the defined feature types and instances This can be done by using the following functions For all kinds of representation ASCII FEGRAMED or the print modes described in section 7 will be considered 5 18 1 Printing to the Interactive Screen or to Streams ASCII The following four functions call the print function PRINT FS of the UDiNe system which is defined in package UNIFY It prints feature structures either to the standard output default or to streams e g text files For internal details we refer to the YDiNe documentation The output format of the TDC type entries is described in this manual in section 7 e function plp type print option 1 plp prints the local prototype of the feature structure with
57. e disjunctions 18 SIMPLIFY FS Px 29 skeleton 16 skeleton 38 SORT 30 70 sort 14 sort p 57 sorts 57 sorts built in 15 sorts 38 SOURCE GRAMMAR 30 31 start collect unified types 41 statements 5 statistics 39 status 25 stream 44 string 15 structure sharing 17 surface 38 switches 28 31 symbol 15 system tdl 4 tdl grapher 54 tdl2latex 46 table 39 td1 file extension 31 59 TDL grapher 54 TPL mode for Emacs 59 TDL grapher button 55 tdl built ins tdl 15 tdl graph ps 55 tdl indent command 59 tdl indent region 59 tdl mode 59 tdl mode el 59 tdl2asl 56 7 DE213TEX 54 7 DE21A1EX 46 template call 23 definition 25 environment 25 parameter 23 templates 38 threshold 41 TITLE 52 title 49 TITLE COMMAND 52 toggle autoredraw grapher button 55 TOP 30 TOP 57 top 10 30 top node grapher button 55 TOP SORT 30 TOP SYMBOL 10 30 TRACE P 20 INDEX tune types 41 type 57 type delete 38 environment 14 expand 32 hierarchy 54 reset prototype 38 TYPE COMMAND 52 TYPESTYLE 49 51 typestyle 49 UDiNe 43 56 unify input file 4l unknown 25 UPDATE GRAPHER OUTPUT P 30 55 USE CONJ HEURISTICS 33 use conj heuristics 33 USE DISJ HEURISTICS 32 use disj heuristics 33 USE INTERMEDIATE TYPES P 29 USE MEMOIZATION P 29 value restriction 23 value types 38 variables 28 VERBOSE EXPANSION P 29 33 VERBOS
58. e g a A b c If style has value prefix complex type entries will be printed in prefix LISP like notation e g AND a b c e print title pflag default value value of variable PRINT TITLE P nil possible values tlnil If flag is t a title with type or instance will be printed at the bottom of the feature structure If flag is nil no title will be printed e domain domain default value value of variable DOMAIN possible values name of a valid domain only in TPE e poster flag default value value of variable POSTER nil If t van Zandt 93 Ps poster macros are used to print large feature structures on as many sheets as are needed This variable only inserts input poster and begin Poster end Poster and forces math math mode e pprint lists flag default value value of variable PPRINT LISTS t possible values tlnil If flag is t lists will we printed using the notation If nil the internal FIRST REST encoding will be used e title title default value possible values nil string prints a title at the bottom of a feature structure e index number default value 0 This keyword is valid only for TDC statements 11p and 1gp Its purpose is to select the index of a instance Example Modifying the Output Style The follovving settings can be used for an output style as it is used in Carpenter 931 MY DOMAIN TYPE set switch ATOM COMMAND newcommand atom 1
59. el command alias prints a list of available abbreviations Alias Description composer start allegro composer fegramed initialize fegramed fgi fegramed global instance fgp fegramed global prototype fli fegramed local instance flp fegramed local prototype grapher start grapher system lgi LaTeX global instance lgp LaTeX global prototype lli LaTeX local instance llp LaTeX local prototype pgi print global instance pgp print global prototype pli print local instance plp print local prototype recompute recompute grapher tdl start tdl reader composer recompute and fegramed may also be abbreviated by com rec and feg All top level commands take the same parameters as the corresponding 7D LisP functions described in the sections before For compatibility reasons we recommend that top level commands be used in the interactive mode only but not in the 7DC grammar files Important Note Parameters of top level commands should not be quoted Example lt MY DOMAIN TYPE gt pgp agr en type label hide list G V OBL but MY DOMAIN 49 PGP agr en type label hide list GOV OBL tdl composer and fegramed don t take any parameter In addition to these TPL specific commands the user may define its own abbreviations Details are described in the ALLEGRO COMMON LISP manual Fra 92 61 10 Sample Session Mode TDL Parametrized Type Expansion in TDL Demo file defdomain DEMO built in
60. elligent Engineering Systems O Intelligent User Interfaces Computer Linguistics O Programming Systems O Deduction and Multiagent Systems O Document Analysis and Office Automation The DFKI strives at making its research results available to the scientific community There exist many contacts to domestic and foreign research institutions both in academy and industry The DFKI hosts technology transfer workshops for shareholders and other interested groups in order to inform about the current state of research From its beginning the DFKI has provided an attractive working environment for Al researchers from Germany and from all over the world The goal is to have a staff of about 100 researchers at the end of the building up phase Dr Dr D Ruland Director TDL A Type Description Language for HPSG Part 2 User Guide Hans Ulrich Krieger Ulrich Schafer DFKI D 94 14 This vvork has been supported by a grant from The Federal Ministry for Research and Technology FKZ ITWM 9002 0 Deutsches Forschungszentrum f r K nstliche Intelligenz 1994 This vvork may not be copied or reproduced in vvhole of part for any commercial purpose Permission to copy n whole or part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following a notice that such copying is by permission of the Deutsche Forschungszentrum f r K nstlic
61. ent with other types as a result of their feature constraints Such a training session consists of the following steps 1 load and expand a grammar 2 call Start Collect Unified Types 3 do train parses 4 call tune types To work with the tuned types later on simply type 1 include glb types load the additional GLB type definitions optional 2 load simplify memo table filename cnf memo table before run time Of course the user is responsible for updates of the files if the type hierarchy as changed e function start collect unified types domain domain This function enables a training session resets some variables and clears some tables e function 1oad simplify memo tablel domain domain filename string loads type simplification memoization table from a file written with tune types or save simplify memo table e function print unified types filename string domain domain prints contents of the global hashtable unified types to screen or to file if filename string is given e function tune types domain domain threshold integer unify input file nil string create glbs nil t hashtable hashtable assume consistency nil t memo output file string glb output file string Main function Either takes the current unify table default or loads one from file unify input file that has been written with print unified types Tune Ty
62. erit amp attrib 1 amp value COPY 1 makes it possible to generate the following types using template calls top level call a template 26 4 SYNTAX OFTDE is a top level template call vvhich vvill result in the feature structure top level call PHON 1 COPY 1 vvhile inside call top attrib a template value hello attrib MY PHON is a template call inside a feature type definition which will result in the feature structure inside call avm TOP ATTRIB MY PHON hello pen hello Disjunction and coreference names in template definitions are local to each template expansion In this sense templates are similar to COMMON LISP macros options in template definitions are the optional keywords author date anddoc If used a keyword must be followed by a string The default value for the author string is defined in the global variable DEFAULT AUTHOR The default value for the doc string is defined in the global variable DEFAULT DOCUMENTATION see Section 5 The default value for date isa string containing the current time and date Section 5 17 describes the function describe template which prints information about template defini tions 4 9 Instance Environment and Instance Definitions A type environment starts with begin instance and ends with end instance It may appear anywhere within a domain environment and may contain arbitrary instance definitions en
63. ex number defines control information for the expansion of a type or an instance For further details see section 5 4 4 11 Lisp Environment A LISP environment starts with begin lisp and ends with end lisp The LISP environment allows insertion arbitrary LISP code into TDL grammars Example begin lisp DEFUN String Append rest args APPLY CONCATENATE STRING args end lisp This DEFUN defines the function String Append used in the example of Section 4 6 15 There is also a short notation for evaluating LISP expressions from FDL The macro leval Common Lisp Expression evaluates Common Lisp Expression in any environment For the sake of clarity we recommend using this statement only in the interactive mode Example leval LOAD SYSTEM my parser 4 12 Comments after an arbitrary token or at the beginning of a line inserts a comment which will be ignored by the TD reader until end of line A comment associated with a specific type template or instance definition should be given in the doc string at the end of the definition and 4 can be used to comment regions as in COMMON LISP 28 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES 5 Useful Functions Switches and Variables The following functions and global variables are defined in the package TDL and are made public to all user defined domains implemented by COMMON LISP packages via use package This is done automatically in the fu
64. example More than two alternative lists per index are allowed All alternative lists with the same index must have the same number n of alternatives The disjunction index is local in every type definition and is normalized to a unique index when unification of feature structures takes place 20 4 SYNTAX OFTDE In general if alternative a 1 lt j n does not fail it selects the corresponding alternative b ci in all other alternative lists with the same disjunction index As in the case of simple disjunctions disjunction alternatives must not contain coreferences refering to values outside the alternative itself But for distributed disjunctions there is an exception to this restriction disjunction alternatives may contain coreferences to values in another distributed disjunction if both disjunctions have the same disjunction index and the alternative containing the coreference has the same position in the disjunction alternative list An example of such a distributed disjunctions with coreferences is dis2 a name 1 2 b name c x amp d 1 g amp m 11 x amp d 2 g m 11 1 dis2 8 A name 8 al c B name i L E b l 4 6 11 Lists In TDC lists are represented as first rest structures with distinguished attributes FIRST and REST where the sort null at the last REST attribute indicates the end of a list and of course the empty list
65. finitions or as variables e g where 8 9 undef undef function call is explained in the following section 4 6 15 Functional Constraints Functional constraints define the value of an attribute on the basis of a function which has to be defined and computed outside the system The syntax of functional constraints is similar to that of external coreference constraints i e functional constraints must be specified outside a feature structure but are connected with it through a coreference tag cf last section function call function name disjunction 1 disjunction String concatenation is a nice example of the use of functional constraints add prefix WORD word PREFIX prefix WHOLE whole 1 where whole String Append prefix word The definition of the LISP function String Append is shown in the example in Section 4 11 The usual representation for functional constraints is add prefix WORD PREFIX WHOLE 4 6 Type Environment and Type Definitions 23 Functional Constraints String Append 2I Hi The evaluation of functional constraints will be postponed until all parameters are instantiated residuation cf Ait Kaci amp Nasr 86 Smolka 91 for theoretical backgrounds The evaluation can be enforced by using the function EVAL CONSTRAINTS of the UNIFY package Further details are described in Backofen amp Weyers 95 4 6 16 Template Calls Templates are pure textual macr
66. from the memo tables If integer is nil all entries will be removed default The threshold keyword is only supplied with the statistics module e function print simplify memo tables domain domain threshold integer prints the contents of the simplification memo tables If the threshold number is specified only entries that have been used more than integer times will be printed If integer is nil all entries will be printed default The threshold keyword is only supplied with the statistics module e function save simplify memo table domain domain filename string threshold integer saves type simplification memoization table to a file The threshold keyword is only supplied with the statistics module All entries occurring less than integer times will not be saved e function load simplify memo table domain domain filename string loads type simplification memoization table from a file written with tune types or save simplify memo table This may speed up subsequent unifications 5 11 Tuning up Unification Training Sessions 41 5 11 Tuning up Unification Training Sessions In this section some tools vvill be described that may be used to speed up unification at run time A training session is necessary 1 to extract type definitions for GLB types if the result of the unification of their expanded definitions is consistent 2 to generate a table of sets of types that are inconsistent or consist
67. ger Klaus Netter G nter Neumann Stephan Oepen and Stephen P Spackman DISCO An HPSG based NLP System and its Application for Appointment Scheduling In Proceedings of the 15 International Conference on Computational Linguistics COLING Kyoto Japan 1994 also as DFKI Research Report RR 94 38 Uszkoreit 91 Hans Uszkoreit Adding Control Information to Declarative Grammars In Proceedings of the 297 Annual Meeting of the Association for Computational Linguistics ACL pp 237 245 Berkeley CA 1991 van Zandt 931 Timothy van Zandt Documentation for postertex poster sty Posters and banners with generic TEX May 1993 Documentation included in the poster distribution ftpable from most TEX sites
68. h element in a list will be replaced by the right side All other coreferences will be left unchanged arraystretch number default value value of variable ARRAYSTRETCH 1 1 This parameter sets the vertical distance between attribute names or disjunction alternatives number is a factor which will be multiplied with the standard character height arraycolsep string default value value of ARRAYCOLSEP 0 3ex This parameter sets the left and right space between braces or brackets and attribute names or values string must contain a IATEX length expression 5 18 Printing Feature Structures 49 doc header string default value value of DOC HEADER This parameter sets the IATEX Ndocumentstyleor documentclass header if latex header p is t Default value is NNdocumentstyle articlej It could be replaced by a document style with additional options such as a4 times etc or for new IAIEX Goossens et al 94 by documentclass article usepackage times e mathmode string default value value of MATHMODE displaymath This parameter sets the IATEX display mode for feature structures It must be a string consisting of the name of a TATEX or user defined math mode environment name e g math displaymath or equation e typestyle style default value value of variable TYPESTYLE infix possible values infix prefix If style has value infix complex type entries will be printed in infix notation
69. he Intelligenz Kaiserslautern Federal Republic of Germany an acknowledgement of the authors and individual contributors to the work all applicable portions of this copyright notice Copying reproducing or republishing for any other purpose shall require a licence with payment of fee to Deutsches Forschungszentrum f r K nstliche Intelligenz ISSN 0946 0098 TDL A Type Description Language for HPSG Part 2 User Guide Hans Ulrich Krieger Ulrich Sch fer krieger schaefer Qdfki uni sb de German Research Center for Artificial Intelligence DFKT Stuhlsatzenhausweg 3 D 66123 Saarbr cken Germany Abstract This documentation serves as a user s guide to the type description language TD which is employed in natural language projects at the DFKI It is intended as a guide for grammar writers rather than as a comprehensive internal documentation Some familiarity with grammar formalisms theories such as Head Driven Phrase Structure Grammar HPSG is assumed The manual describes the syntax of the TDE formalism the user accessible control functions and variables and the various tools such as type grapher feature editor 7 DE21ATEX Emacs 7DE mode and print interface I We would like to thank Elizabeth Hinkelman for reading a draft version of this manual 2 CONTENTS Contents 1 Introduction 4 2 The 72 System 4 3 Starting TDL 4 4 Syntax of TDL 5 4 11 DEBE Gre hts vd aem Sas ae BD gt DE ee ap it us 5 4 1 1 Main Construct
70. he current implementation e incompatible types nil type I type declares the types to be incompatible This declaration is useful for avm types in an open world i e if AND OPEN WORLD REASONING P has value t e exhaustive partitions supertype type type declares an exhaustive partition cf Krieger amp Sch fer 94a disjoint exhaustive partitions supertype type type declares an exhaustive disjoint partition cf Krieger amp Sch fer 94a All other relations between types conjunctions disjunctions must be defined in the type environment The type hierarchy for avm types will be inferred from the avm type definitions In addition the following domain specific symbol lists can also be declared in this environment cf Section 4 2 hide valuelsl identifier 1 identifier specifies the attributes whose values are to be hidden at definition time e hide attribute s identifier identifier specifies the attributes including their values to be hidden at definition time e export symbolls identifier 1 identifier specifies the symbols to be exported from the domain package All declarations must be specified directly in a declare environment and nowhere else 4 6 Type Environment and Type Definitions A type environment starts with begin type and ends with end type It may appear anywhere within a domain environment and may contain arbitrary type defin
71. ibute names types etc They may be changed for user purposes e Global variable FILEPATH default value 7 tmp possible values a pathname or pathname string specifies the path where tex dvi and other files go 5 18 Printing Feature Structures 51 Global variable SHELL COMMAND default value tdl2latex possible values nil or a string containing a shell command name specifies a shell command to run on output file e g latex If nil no shell process will be started Global variable LATEX HEADER P default value t possible values t or nil if nil no IATpgX header documentstyle etc will be written to output file Global variable POSTER default value nil possible values t or nil If t van Zandt 93 s poster macros are used to print feature structures on as many sheets as are needed This variable only inserts input poster and begin Poster end Poster and forces math math mode Global variable PPRINT LISTS default value t possible values t or nil If t lists will we printed using the notation If nil the internal FIRST REST encoding will be used Global variable PRINT TITLE P default value nil possible values t or nil if nil no title default type or instance will be printed Global variable ALIGN ATTRIBUTES P default value nil possible values t or nil if nil attributes and values will not be aligned Global variable FONTSIZE default value normalsize possible
72. ics domain domain stream stream prints expansion statistics If domain is not specified the current domain is assumed e function print global statistics stream stream prints all statistical information that is domain independent e function print simplify statistics domain domain stream stream prints type simplification statistics If domain is not specified the current domain is assumed e function reset all statistics domain domain resets all statistical information If domain is not specified this will be done for all domains e function reset domain statistics domain domain resets all statistical information that is domain specific If domain is not specified the current domain is assumed e function reset expand statistics domain domain reset expansion statistics If domain is not specified the current domain is assumed e function reset global statistics resets all statistical information that is domain independent e function reset simplify statistics domain domain resets type simplification statistics 40 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES e function count nodes type instance a11 table avms instances expand p t ni1 verbose t ni1 domain domain index index stream stream filename nil filename counts the number of nodes in an avm type or instance with the specified index default is nil for types and for instances Instead of a n
73. in domain domain and end domain domain are defined or looked up in domain All other environments except the 1isp environment must be enclosed by at least one domain environment See Section 4 2 for more details 4 5 Declare Environment and Declarations A declare environment starts with begin declare and ends with end declare 14 4 SYNTAX OFTDE It may appear anywhere within a domain environment and may contain arbitrary declarations other environments and DC statements Declare environments declare built in sort symbols built in s type pe built in declares a COMMON LISP type to be a sort in TD e g integer string etc A built in sort can be unified only with its subsorts or with an atom that has the corresponding COMMON LISP type An example is shown in section 4 6 2 Note that the standard FDE type built in itself is an ordinary sort but is not declared to be a built in type Its only purpose is to be the super sort of all predefined sorts in TDC such as null and the atomic sorts e g atom string etc e sort symbols sort s type type sort declares types to be sorts singleton sorts in Smolka s terminology Sorts always live in a closed world i e their unification fails unless they subsume each other or have a greatest lower bound This declaration is optional It is equivalent to the definition type lt sort inthe type environment which may be faster at definition time in t
74. itions other environments and TD statements The syntax for subsort and subtype definitions is type 1 type option Subsort or subtype definitions define the order of sorts or types without feature constraints They are not necessary if feature constraints are specified for a subtype Example avm lt top 4 6 Type Environment and Type Definitions 15 but cons avm first rest In both cases the left hand side is a subtype of the right hand side type The general syntax of type definitions is type body 1 option type is a symbol the name of the type to be defined The complex BNF syntax of body is given in Section 4 1 2 Some examples are presented on the following pages 4 6 1 Feature Structure Definitions The 7D syntax for a feature structure type person number type with attributes PERSON and NUMBER is person number type PERSON NUMBER The definition results in the structure person number type PERSON NUMBER If no value is specified for an attribute the empty feature structure with the top type of the type hierarchy will be assumed Attribute values can be atoms feature structures disjunctions distributed disjunctions coreferences lists functional constraints template calls or negated values 4 6 2 Atoms In TDC an atom can be a number a string or a symbol Symbols must be quoted with a single quote otherwise they will be interpreted as sorts or avm types
75. keys do infon infon keys expand all instances expand option expand all types expand option expand instance instance index integer expand option expand type type index index expand option fegramed f gi fli instance fegramed option fgp flp type fegramed option get svitch identifier grapher help identifier include filename ldt leval Common Lisp Expression 1gi 113i instance latex option 1gp 11p type latex option message string Common Lisp Expression 1oad simplify memo tablel domain domain filename filename pgi pli instance print option pgp plp pe print option print all names infon keys print all statistics domain domain stream stream print appropl domain domain print control type instance global print domain statistics domain domain stream stream print expand statistics domain domain stream stream print global statistics streams ream print recursive sccs domain domain print simplify memo tables domain domain stream stream threshold integer print simplify statistics domain domain stream stream print switch identifier print unified types filename string domain domain recompute reset all instances domain rese
76. ll statements are defined as functions The only macros defined by the TDL system are defcontrol leval alias print control print switch set switch and vith print mode Examples pgp agr type label hide list x y z but defcontrol agr type delay u x v x y It is important not to forget the dot delimiter at the end of TD expressions since the TD reader will wait for it It is possible to mix LISP code and FDE definitions in a file Some examples are shown in Section 4 3 Newline characters spaces or comments Section 4 12 can be inserted anywhere between tokens symbols braces parentheses etc 41 TDL BNF The TD syntax is given in extended BNF Backus Naur Form Terminal symbols characters to be typed in are printed in typewriter style Nonterminal symbols are printed in italic style The grammar starts with the start production The following table explains the meanings of the metasymbols used in extended BNF metasymbols alternative expressions one optional expression one or none of the expressions exactly one of the expressions n successive expressions where n 0 1 n successive expressions where n 1 2 6 4 SYNTAX OF TPL 4 1 1 TPL Main Constructors start 3 block statement block begin control type def instance def start end control begin declare declare start V end declare begin domain domain start end domain domain begin insta
77. lly and globally specified lists will be taken into account 5 4 4 Printing Control Information The TD statement macro print controll type instance global prints the control information in an internal format with path patterns replaced by a special syntax function print recursive sccs domain domain prints the stronlgy connected components of the recursive dependency graph computed so far It contains recursive types recognized so far by type expansion Example print recursive sccs CONS LIST APPEND APPEND1 5 4 5 How to Stop Recursion Type expansion with recursive type definition is undecidable in general i e there is no complete algorithm that halts on arbitrary input type definitions and decides whether a description is satisfiable or not However there are several ways to stop infinite expansion e The first method is part of the expansion algorithm If a recursive type occurs in a typed feature structure that is to be expanded and this type has been expanded under a subpath and no features or other types are specified at this node then this type will be delayed since it would expand forever this is called lazy expansion An example of a recursion that stops like this is the recursive version of the list type see below A counter example i e a type that will not stop without a finite input using the default resolved predicate alvays false and no delay pattern is Ait Kaci s append type
78. me The global variable CHECK WELLTYPEDNESS P values t or nil controls whether this check is done t or not nil This check enforces expansion at definition time 2 at run time The global variable CHECK UNIFICATION WELLTYPEDNESS P values t or nil controls whether this check is done t or not nil The global variable RETURN FAIL IF NOT WELLTYPED P values t or nil controls whether a unification failure is triggered if the unified nodes are not welltyped t 3 for a specific type or instance The function check welltypedness type instance all instances avms domain domain index index verbose t ni1 provides such a check for a single type or instance as well as for all types or instances with the specified index The global variable VERBOSE WELLTYPEDNESS CHECK P controls whether a warning is given if a welltypedness check is negative t Below we show a brief example output of print approp Feature Intro Type Value Type QUE NON LOCAL TYPE TOP SLADJ NON LOCAL TYPE TOP SLASH NON LOCAL TYPE TOP HOUR TIME VALUE TOP NON LOC NON LOCAL NON LOCAL TYPE SUBJ SC SUBJ SUBCAT TYPE TOP LIST DIFF LIST SEM MOOD QUESTION SEMANTICS SYMBOL SUBCAT SUBCAT TYPE TOP FILLER DTR FILLER DTR TYPE MAX SIGN TYPE 6 Carpenter 93 Chapter 6 calls such an appropriateness condition unacceptable and stipulates that there exists
79. n the following structure give RELN give GIVER 1 12 11 GIVEN GIVEE 4 6 9 Simple Disjunctions Disjunction elements are separated by or VI in the Emacs interaction mode cf Section 4 6 4 Disjunction elements can be atoms conjunctive feature descriptions simple disjunctions distributed disjunctions lists template calls or negated values In simple disjunctions the alternatives must not contain coreferences to values outside the alternative itself see Backofen amp Weyers 95 for the reasons Distributed disjunctions provide a restricted way to use coreferences to outside disjunction alternatives Section 4 6 10 An example of disjunctions in a type definition person 1 or 2 SYN person number type PERSON 1 person number type amp PERSON 2 The resulting feature structure is person 1 or 2 person number type PERSON 1 person number type PERSON 2 Another more local specification of the same disjunction would be person 1 or 2 SYN person number type PERSON 1 2 1 The resulting feature structure is person 1 or 2 person number type een Disjunctions at the top level of a type definition introduce disjunctive types depicted as bold edges in the grapher Arbitrary combinations of sorts atoms and feature structure types are allowed Example 4 6 Type Environment and Type Definitions 19 list null cons where null is a sort cons an a
80. nce instance def start end instance begin lisp Common Lisp Expression end lisp begin template 1 femplate def start end template begin type I type def start end type 4 1 2 Type Definitions type def type 1 avm def subtype def type identifier avm def body 1 option nonmonotonic where constraint constraint Y 11 option body disjunction gt list where constraint I constraint 1 disjunction conjunction 4 conjunction conjunction term term term type atom feature term diff list list coreference distributed disj templ par templ call term disjunction atom gt string integer identifier feature term I attr val 1 attr val attr val gt attribute restriction 1 attribute restriction disjunction 1 attribute o identifier templ par restriction conj restriction 4 conj restriction conj restriction basic restriction amp basic restriction basic restriction type basic restriction templ par restriction diff list gt lt disjunction disjunction gt type list 3 lt gt nonempty list gt list restriction nonempty list disjunction disjunction disjunction 1 disjunction disjunction list restriction restriction type integer integer integer coreference tt
81. nction defdomain 5 1 Global Switches and Variables The following global LISP variables can be set by the user Switches are set to t for ON or nil for OFF Global variable AND OPEN WORLD REASONING P default value t possible values t or nil This variable controls whether avm types live in an open or in closed world Cf Krieger amp Sch fer 94a Global variable SIGNAL BOTTOM P default value t possible values t or nil If t an error is signaled if the conjunction of two types is bottom Global variable IGNORE BOTTOM P default value nil possible values t or nil If t typed unification skips over bottom The result of an inconsistent type conjunction will be the bottom type and feature unification will be continued as if the conjunction would be consistent This is useful to debug a grammar Global variable WARN IF TYPE DOES NOT EXIST default value t possible values t or nil This variable controls whether a warning will be given if a type definition contains the name of an undefined type in its body Global variable WARN IF REDEFINE TYPE default value t possible values t or nil This variable controls whether a warning will be signaled if a type already exists and is about to be redefined Global variable ACCUMULATE INSTANCE DEFINITIONS default value nil possible values t or nil If t redefining an instance will push the new definition onto a stack Otherwise new definitions will replace older ones
82. ng of list structures without requiring an append type or an append relation In TDC the elements of difference lists may be enclosed in lt gt as an abbreviation Example difflist3 c 0 0 0 gt difflist3 cons FIRST cons LIST FIRST REST cons REST FIRST REST LAST 22 4 SYNTAX OFTDE 4 6 13 Negation The sign indicates negation Example not mas type GENDER mas 1 The resulting feature structure is not mas type GENDER mas Negation of types will be pushed down to atoms according the schema of Smolka 88 Smolka 89 If 1ist list is defined as in the td1 built ins tdl file page 4 2 the definition notlist list will result in the following expanded structure cons A null null FIRST undef null REST undef Here unde indicates undefined attributes It is an atom that unifies with nothing else 4 6 14 External Coreference Constraints Instead of specifying the values of coreferences within a feature structure it is also possible to add a list of such constraints at the end of a feature type definition The syntax is Where constraint constraint where constraint coref name function call disjunction Here mean the body of a type instance or template definition External coreference constraints are pure syntactic sugar but may be useful e g for expressing the identity of coreferences in very complex de
83. nil TPL type expansion will only print messages when types are not defined or inconsistent Otherise a verbose trace of the expansion will be printed Global variable TRACE P default value nil possible values t or nil If t verbose trace information is printed by the 7D parser the definition functions and the expansion algorithm Global variable LAST TYPE default value undefined possible values a type symbol This variable contains the name of the last type defined It is used by the print functions pgp plp lgp 11p fgp flp and by expand type delete type and reset proto when no type name is specified The value of this variable can be changed by the user Global variable LAST INSTANCE default value undefined possible values an instance symbol This variable contains the name of the last instance defined Tt is used by the print functions pgi pli 1gi lli fgi fli and by expand instance delete instance and reset instance when no instance name is specified The value of this variable can be changed by the user Global variable USE MEMOIZATION P default value t possible values t or nil If nil no memoization of simplified type expression will take place Otherwise the domain specific hash tables will be used Global variable EXPAND TYPE P default value nil possible values t or nil If nil feature structures i e avm types and instances will not be expanded at definition time This saves time and space
84. nil all attributes except those in label hide list will be printed label hide list identifier default value value of LABEL HIDE LIST possible values a list of symbols attribute names Attributes in the list will not be printed label sort list identifier default value value of variable LABEL SORT LIST possible values a list of symbols attribute names The list defines an order for attributes to be printed Attributes of the feature structure will be printed first to last according to their left to right position in the list All remaining attributes which are not member of the list will be printed at the end shell command command default value value of SHELL COMMAND tdl2latex possible values nil string If command it nil only the IATEX file will be created and 7DC2IATgX will return If command is a string 7DC2IATEX will start a shell process and execute command with parameter filename An example for command is the following shell script with name tdl2ps which starts LATEX with the output file of 7DC2IATEX and generates a PostScript file using Rokicki 93 s DVIPS bin sh tdl2ps generates PostScript file latex 1 dvips 1 o 1 ps The following script td12epsf generates an encapsulated PostScript file EPSF When generated with a PostScript font such as option times in the document header the EPSF file can be used to scale a feature structure in order to fit into an arbitra
85. ntry is printed at all In all other cases the value of the type slot will be printed anyway e HIDE TYPES default value nil possible values t nil used in ascii printing 7 DC2IATEX FEGRAMED If not nil only true UDiNe atoms like fail and undef will be printed TDL atoms sorts and types will not be printed e PRINT SORTS AS ATOMS default value nil possible values t nil used in ascii printing 7 DC2IATEX FEGRAMED If not nil sort symbols will be printed the same way atoms are printed If nil sort symbols will be printed like type symbols type sort Conjunctions or Disjunctions of Sorts are always printed with type and or e PRINT SLOT LENGTH default value 16 possible values nil or a number used in ascii printing only If a slot is longer than 16 characters a newline character will be printed nil no limit e PRINT NEWLINE default value nil possible values t nil used in ascii printing only Prints a newline after each type entry except before empty label lists 58 7 PRINT READ SYNTAX FOR TD TYPE ENTRIES 7 3 BNF The BNF for typed feature structures input and output for ascii is node atom type info Cidentifier node 11 type info node node y type info type type expr complete t ni1 delta nil type expr expanded t ni1 restriction type expr sort p t nil type expr identifier and type expr
86. of expanded lexicon entries etc The default index is nil which is the standard prototype If no special control information is given locally or globally the nil index specifies a fully expanded prototype The skeleton index may be useful at the expand only or expand slot It denotes the unexpanded definition of a type its skeleton skeleton cannot be used as an argument for the defcontrol keyword index because a skeleton is always unexpanded and expansion is permitted expand type will generate a new prototype with index index from a copy of the skeleton of type type if this index does not exist If it exists and is not already fully expanded it will be expanded again 5 4 3 The Syntax of expand control If expand control is specified for expand instance or expand type the values of slots that are omitted will be inherited from global control Control information which has been defined for the type or instance with the same index will be ignored If some slots in defcontrol global are omitted they will be taken from global variables with corresponding names MAXDEPTH ATTRIBUTE PREFERENCE EXPAND FUNCTION RESOLVED PREDICATE IGNORE GLOBAL CONTROL ASK DISJ PREFERENCE USE DISJ HEURISTICS or 5 4 Expanding Types and Instances 33 type name index feature structure definition XyZ skeleton of xyz default prototype uvw skeleton definition of uvw fully e
87. omain 10 delete all instances 38 delete instance 38 delete package p 10 delete type 38 deleting instances 38 deleting types 38 delta 57 describe template 42 DIFF LIST 31 DIFF LIST TYPE SYMBOL 31 difference list 21 disjoint exhaustive partitions 14 disjunctions distributed 19 with coreferences 20 simple 18 distributed disjunctions 19 with coreferences 20 do all infons 39 do infon 39 DOC HEADER 49 51 doc header 49 doc 25 27 28 documentation 10 DOMAIN 49 domain 9 define 10 delete 10 domain 39 41 49 domain 38 domain environment 13 domain grapher button 54 dotted pair list 20 Emacs 59 EMPTYNODE COMMAND 52 encoding grapher button 55 end 11 END OF LIST 31 environment 11 control 27 declare 13 instance 26 lisp 27 template 25 type 14 EPSF 47 errorp 10 EVAL CONSTRAINTS 23 67 eval current tdl expression 59 eval tdl expression 59 eval tdl file 59 eval tdl region 59 eval tdl region and go 59 exhaustive 56 exhaustive partitions 14 exit TDL 5 42 exit grapher button 54 expand 33 expand grapher button 55 expand all instances 32 expand all types 32 expand control 27 expand control 38 expand control 25 EXPAND FUNCTION 32 expand function 33 expand instance 32 expand only 33 expand type 32 55 EXPAND TYPE P 29 expanded 57 expanding types and instances 32 expansion 32 export symbol 14 export symbols
88. opriateness 37 ARRAYCOLSEP 48 52 arraycolsep 48 ARRAYSTRETCH 48 52 arraystretch 48 ASCII printing 43 ASK DISJ PREFERENCE 32 ask disj preference 33 assume consistency 41 atom 15 ATOM COMMAND 52 atomic symbols 38 atoms 57 ATTRIB COMMAND 52 attribute restriction 23 ATTRIBUTE PREFERENCE 32 attribute preference 33 attributes 38 author 38 author 25 28 avms 57 avms 38 66 backslash 16 backup grapher button 55 begin 11 BOTTOM 30 bottom 10 BOTTOM SYMBOL 10 30 BUILD INTERMEDIATE TYPES P 29 built in 14 built in sorts 15 buttons 54 CHECK UNIFICATION WELLTYPEDNESS P 37 check welltypedness 37 CHECK WELLTYPEDNESS P 37 choose grapher button 54 class info 38 clear simplify memo tables 40 comment 38 comments 27 COMMON LISP 27 COMMON LISP packages 9 complete 57 compute approp 37 CONS 31 CONS TYPE SYMBOL 31 constraints functional 22 control environment 27 COREF COMMAND 52 coreferences 17 external 22 negated 18 COREFFONT 48 51 coreffont 48 COREFSIZE 48 51 corefsize 48 COREFTABLEx 48 51 coreftable 48 count nodes 40 create glbs 41 CREATE LEXICAL TYPES P 30 creation index 38 date 38 date 25 debug 56 declare environment 13 default 56 DEFAULT AUTHORx 25 28 DEFAULT DOCUMENTATION 25 28 defaults 23 INDEX defcontrol 5 25 27 defdomain 10 30 DEFSYSTEM 4 delay 33 deld
89. ors 6 4 12 Type Definitions 22 2 22 ew e vu 6 4 1 3 Instance Definitions 7 4 1 4 Template Definitions 7 41 5 Declarati ons i vu 22 bomo we SAGE pup E An geli 7 4 16 Statements emm en AS a Sat NUN Se SE 8 4 2 Creating and Changing Domains 9 4 3 The Structure of TDL Grammars 11 4 4 Domain Environment 13 4 5 Declare Environment and Declarations 13 4 6 Type Environment and Type Definitions 14 4 6 1 Feature Structure Definitions 15 462 Atoms ur Show Ke TAA 15 4 6 3 sa he Pkt kn eod de PT Le beat 16 4 64 Logical Operators eur a mom m Hokey SL Ser te ar ke ie 16 4 6 5 Type Specification and Inheritance 2 16 4 6 6 Multiple Inheritance 17 46 7 Coreferences eM ER S PSR Ge 17 4 6 8 NegatedCoreferences 18 4 6 9 Simple Disfunctions 00000000 18 4 6 10 Distributed Disjunctions 19 JM Dec DDR ard 7 20 4 612 Difference LISIS nm ne momo m FE MR s s d li Bl GE ss LEE 21 ALGAS Negation ua p 8 Lek ee gh ge sem ae ok 22 4 6 14 External
90. os which allow specification of parts of type or instance definitions by means of some shorthand The definition of templates will be explained in Section 4 8 A template call simply means the syntactic replacement of a template name by its definition and possibly given parameters Thus we restrict templates to be non recursive The syntax of template calls is templ name templ par 1 templ par where a fempl par is a pair consisting of a parameter name starting with the character followed by and a value All occurrences of the parameter name will be replaced by the value given in the template call or by the default value given in the template definition See Section 4 8 for further details and examples 4 6 17 Nonmonotonicity and Value Restrictions TPL supports nonmonotonic definitions for avm types and instances called single link overwriting SLO A type can be overwritten by a set of paths with associated overwrite values The general syntax for nonmonotonic definitions is identifier nonmonotonic where constraint 1 constraint option where nonmonotonic type amp overwrite path overwrite path 1 and overwrite path identifier 1 identifier disjunction This feature of FDL can be used to model defaults A special extension of typed unification will handle nonmonotonic unification in a future version of TPL Krieger 93 Currently one has to be careful when using this feature A suit
91. pes creates a memo output file default name cnf memo table as well as a g1b output file default name glb types tdl The first file can be loaded at run time with load simplify memo table the second one with include If create glbs nil is specified no glb types will be introduced default t and glb output file will be created threshold integer specifies a threshold for the entries in the table of unified types to be considered Only entries that have occurred at least integer times will be considered default O all entries assume consistency t is a sensible default because it assumes that all type expressions that occur as an argument of an entry in the unify table are consistent Otherwise it would unify expand all arguments hashtableis one of simplify cnf hierarchy default simplify cnf simplify dnf hierarchy or simplify dnf and specifies the corresponding type memoization hashtable 42 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES 5 12 Defining Reader Macros The alias facility allows extension of the 7D syntax by adding new macros that may abbreviate TD syntax or integrate other modules like parsers or other user shells macro alias identifier definition string nil help string defines a user macro with name name string or symbol and definition definition string definition string must start with a COMMON LISP function or macro name without surrounding parentheses followed by arbitra
92. riable WHICH PARSER its default value is the symbol TDL PARSE CONSTRUCT BERNIE for the DISCO parser 4 7 Optional Keywords in Definitions For external use TD provides a number of optional specifications which are basically irrelevant to the grammar except for controlled expansion If the optional keywords are not specified default values will be assumed by the FDE control system Optional keywords are author doc date status and expand control If a keyword is given it must be followed by a value The values of author doc and date must be strings The default value of author is defined in the global variable DEFAULT AUTHOR The default value of doc is defined in the global variable DEFAULT DOCUMENTATION see Section 5 The value of date is a string containing the current time and date If not specified this string will be automatically generated by the system The status information is necessary if the grammar is to be processed by the DISCO parser It distinguishes between different categories of types and type instances e g lexical entries rules or root nodes If the status keyword is given the status value of the type will become the specified one If no status option is given the status will be inherited from the supertype or be unknown if the supertype is the top type of the type hierarchy The expand control keyword can be used to specify control information for type expansion It has the same effect
93. ry arguments Arguments specified with a TD reader macro call will be passed to the COMMON LISP function or macro by simply appending them at the end of the definition string If definition string is nil then name will be defined to call a function or macro with the same name In this case the corresponding symbol must be exported from the TDL or COMMON LISP package help string should contain a string with a brief description of the reader macro It will be printed with the help command see below Example The message command described in the following paragraph is defined as a reader macro as follows alias MESSAGE FORMAT T print a message Lisp s FORMAT syntax 5 13 Printing Messages During parsing the grammar files the function message string Common Lisp Expression can be used to print messages The args may be variable names or LISP function calls as in the COMMON LISP FORMAT function Example message Default author is A DEFAULT AUTHOR 5 14 Help help statement a11 help a11 default prints a list of all statements readermacros that are defined If a statement name is specified a brief description associated with the readermacro will be printed Example lt DISCO TYPE gt help begin Help for begin begin a TDL definition block 5 15 Wait wait waits until the return key is pressed on COMMON LISP s TERMINAL IO useful for demos etc 5 16 Exit TDL ldt quits the syntax rea
94. ry box e g in TEX documents using Vepsfbox see Rokicki 93 To achieve this the output file of 7DC2IATEX must consist of exactly one page Large feature structure may lead to 2 or 3 pages of output In this case add textheight80cm textwidth40cmor so to the file header generated by 7D 2I4TpX Then IATEX should generate one page output that can be scaled arbitrarily If TEX stack size is too small to process large feature structures recompilation of TEX with increased stack size will help 48 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES bin sh tdl2epsf generates encapsulated PostScript file EPSF latex 1 dvips 1 E o 1 epsf td12x generates a dvi file and runs xdvi on it bin sh tdl2x generates a dvi file and starts xdvi latex 1 xdvi 1 wait flag default value value of variable WAIT nil possible values tlnil If flag is nil and command is not ni1 the shell command command will be started as a background process Otherwise DL2IATEX will wait for command to be terminated latex header p lag default value value of LATEX HEADER P t possible values tlnil If flag is t a complete IATEX file with Ndocumentstyle etc will be generated If flag is nil only the IATEX code of the feature structure enclosed in Vbeginifeaturestruct and end featurestruct will be written to the output file This is useful for inserting IATEX feature structures into TATEX documents for papers books etc align
95. s A user definable function is responsible for translating the abstract representation into the desired format Rules can be defined as types and as instances A sophisticated representation of rules e g as used in the DISCO system even allows inheritance from rule types Rule definition syntax is identifier disjunction gt list where constraint constraint where disjunction represents the left hand side of the rule and list contains the right hand side in the TPE list syntax Examples rule the most general rule type pe Ke binary rule Some silly examples to show rule gt gt What is possible np binary rule gt lt Det Noun gt 333 rule inheritance xp yp amp zp gt Cati Cat2 gt ap bp cp dp 1 amp Cati Cat2 1 gt tp sp attr ta amp foo gt fee fum amp rtta fa amp b fuu b gt We show two kinds of representation of the rules here taking the np type from above binary rule cons FIRST det ARGS cons REST FIRST noun Bee null gt internal representation of the DISCO parser cons FIRST binary rule cons np gt FIRST det internal representation of another parser REST cons REST FIRST noun REST null 4 7 Optional Keyvvords in Definitions 25 The name of the function that generates features structures from the rule syntax can be set in the global va
96. s as the def control statement for type with index nil see Section 4 10 4 8 Template Environment and Template Definitions A template environment starts with begin template and ends with end template It may appear anywhere within a domain environment and may contain arbitrary template definitions environments and TDC statements Templates in TDC are what parametrized macros in programming languages are syntactic replacement of a template name by its definition and possibly replacement of given parameters in the definition In addition the specification of default values for template parameters is possible in the template definition Templates are very useful in writing grammars that are modular they can also keep definitions independent as far as possible from specific grammar theories Note that template definitions must not be recursive Recursive definitions are only allowed for avm types The general syntax of a TDC template definition is templ name templ par 1 templ par body 1 option where fempl par is a pair consisting of a parameter name starting with the character followed by and a default value All occurrences of the parameter name will be replaced by the value given in the template call or by the default value given in the template definition body can be a complex description as in type definitions Example The template definition a template inherit avm attrib PHON value inh
97. son y string expand type pxs fgp pxs wait set switch VERBOSE EXPANSION P NIL set switch CHECK WELLTYPEDNESS P T now expand instance will be done automatically begin instance zi zz amp z c amp c 31 x al fgi zi wait end instance set switch CHECK WELLTYPEDNESS P NIL proto config avm amp EDGE NEXT INPUT non final config proto config amp EDGE first NEXT INPUT rest INPUT lt first rest gt final config proto config INPUT lt gt EDGE undef NEXT undef config non final config final config U non final config amp EDGE covary a b c NEXT covary U V V lt final config X non final config amp EDGE a NEXT Y Y non final config amp EDGE b NEXT Y 7 Z config EDGE covary c undef NEXT covary Z undef now we intersect the two automata U and X gt a b c UX U amp X testi UX amp INPUT lt a b c gt accepted test2 UX amp INPUT lt a b b c gt 333 accepted test3 UX amp INPUT lt b c gt 333 is inconsistent 63 test4 UX amp INPUT lt a b c d gt set switch VERBOSE EXPANSION P NIL set switch PRINT SLOT LIST REMOVE expand type test1 fgp testi wait expand type fgp test2 wait expand type expand type wait test2 test3 test4
98. t all protos domain reset all statistics domain domain reset domain statistics domain domain 4 2 Creating and Changing Domains 9 reset expand statistics domain domain reset global statistics reset instance instance domain domain index integer reset print mode reset proto type domain domain index index reset simplify statistics domain domain restore print mode save print mode set print mode print mode set switch identifier Common Lisp Expression start collect unified types domain domain tune types domain domain threshold integer wait with print mode print mode Common Lisp Expression infon keys see Section 5 8 print option domain domain index index stream t nil stream label sort list identifier 1abel hide list identifier remove tops t nil init pos integer latex option domain domain index index hide types t nil filename filename see Section 5 18 3 fegramed option domain domain index index filename filename wait t nil file only t nil defdomain option hide attributes identifier hide values identifier V export symbols identifier Y documentation string top type bottom type load built ins p t nil errorp t nil expand option domain domain expand control expand control
99. tes end template begin type type definitions selfmoving lt moveable lt physical nonmoveable lt physical nonselfmoving lt moveable animated lt moveable non animated moveable organism selfmoving amp animated vehicle selfmoving non animated load template definitions 4 4 Domain Environment include grammar semantic avms end type begin instance instance definitions end instance now we continue with phonology begin declare include grammar phonology declarations end declare begin type include grammar phonology avms end type now a big syntax package include grammar syntax load syntax we finish with bottom declarations begin declare bottom declarations nil undef amp avm nil undef amp built in end declare now let s expand all instances expand all instances message grammar loading done end domain grammar 4 4 Domain Environment A domain environment starts with begin domain domain and ends with end domain domain 13 domain must be the name of a previously defined domain i e a quoted symbol a string or a keyword symbol begin domain pushes domain to the global stack DOMAIN while end domain pops it Arbitrary TDC statements or other environments may be enclosed by the domain environment All symbols sort type template instance names occurring between beg
100. the TDZ mode e key TAB is bound to function tdl indent command indents one line e key ESC C is bound to function tdl indent region indents a whole marked region e g one or more type definitions at once or the whole buffer e key ESC C x is bound to function eval tdl expression evaluates the whole definition where the cursor is in up to a terminating dot at the end of a line e key C s is bound to function eval current tdl expression is currently the same as ESC C x e key C c C r is bound to function eval tdl region evaluates the whole marked region e g one or more type definitions at once or the whole buffer e key C c r is bound to function eval tdl region and go evaluates the marked region and switches to the inferior COMMON LISP buffer e key C c C b is bound to function eval tdl file performs a TD include of the whole file associated with the current buffer e key C c C e is bound to function goto end of tdl expression moves the cursor to the end of a TDL definition or statement e key C c C a is bound to function goto begin of tdl expression moves the cursor to the beginning of TPE definition or statement TPL mode can also be switched on by hand with M x tdl mode 60 9 TOP LEVEL ABBREVIATIONS ALLEGRO COMMON LISP ONLY 9 Top Level Abbreviations ALLEGRO COMMON LISP Only In the ALLEGRO COMMON Lis Fra 92 version of TDL some often used commands are also available as top level abbreviations The top lev
101. the following structure after type expansion poe GENDER mas reso 2 NUMBER 4 6 7 Coreferences Coreferences indicate information sharing between feature structures In TDL coreference symbols may occur anywhere in the value of an attribute If values are specified they are attached to the coreference tag by the connector The order of the elements of such a conjunction does not matter A coreference symbol consists of the hash sign followed by either a number positive integer or a symbol However in the internal representation and in the printed output of feature structures the coreference symbols will be normalized to an integer number Example share pn SYN pn amp person number type SEM pn 1 results in the follovving structure after type expansion share pn person number type SYN PERSON br SEM 18 4 SYNTAX OFTDE 4 6 8 Negated Coreferences Negated coreferences specify that two attributes must not share the same value i e they may have the same value but these values must not be linked to each other by coreferences they may be type identical but must not be token identical The syntax of negated coreferences is Ha d2 Gn where a1 az Gn are coreference symbols i e numbers or symbols without the hash sign If n 1 the parentheses can be omitted Example The TPE definition give PL RELN give GIVER 1 2 GIVEN 1 GIVEE 2 1 would result i
102. types will be loaded automatically begin domain DEMO set switch WARN IF REDEFINE TYPE NIL 333 switch off warnings set switch WARN IF TYPE DOES NOT EXIST NIL dto set switch PRINT SORTS AS ATOMS T for fegramed pgp set switch VERBOSE EXPANSION P T Verbose expansion set switch PRINT SLOT LIST CONS DELTA PRINT SLOT LIST show delta set switch LABEL SORT LIST FIRST REST LAST INPUT EDGE NEXT for output WHOLE FRONT BACK AB C D X Y Z only fegramed start Feature Editor set switch FEGRAMED DEF FILENAME tmp grapher Start Type Grapher begin type ai a 1 b2 b 2 c c 22 z d zz amp x al y b2 z c amp c 311 defcontrol d expand only c 1 EQ z a1 x attribute preference z x y wait expand type d fgp d wait defcontrol d delay c attribute preference z x y expand function types first expand index 1 expand type d index 1 fgp d index 1 wait 62 10 Interactively ask for disjunct order SAMPLE SESSION inter disj all b2 c disj2 b2 d 42 defcontrol inter ask disj preference t expand type inter fgp inter wait xn a 1 b 2 c 3 nx n xn expand type nx fgp nx wait a person_x INTEGER person y INTEGER 1 b a person x 11 21 px3 b amp person x 31 expand type px3 fgp px3 wait pxs b per
103. ue t possible values t or nil If t TDC will be forced to introduce an intermediate type at the top level of an instance definition if necessary At all other levels of an instance definition the variables BUILD INTERMEDIATE TYPES P and USE INTERMEDIATE TYPES P control the behavior of intermediate type genera tion Global variable WARN UNIFICATION P default value nil possible values t or nil Normally no unification takes place at definition time But there are some infrequent cases e g if the grammar writer specifies a conjunction of two feature structures La b x1 b yl which make unification necessary If WARN UNIFICATION P is nil no warning will be given when unification is performed Global variable SOURCE GRAMMAR default value user s home directory pathname possible values a pathname This variable contains the default prefix for grammar files if no absolute pathname is specified for filename in the include statement Global variable LOAD BUILT INS P default value t possible values t or nil This variable contains the default value for the 1oad built ins p keyword in the include statement Global variable WARN NORMAL FORM P default value nil possible values t or nil This variable determines whether a warning is given if a TDL expression is not in normal form only at definition time If nil no such warning will be given Global variable UPDATE GRAPHER QUTPUT P default value nil possible
104. values Tont size string IATFX size for feature structures i e one of tiny scriptsize footnotesize normalsize large Large LARGE huge Huge Global variable COREFSIZE default value nil possible values nil or a string if nil the size for the coreference symbol font will be computed from FONTSIZE orthe fontsize keyword If itisastring it mustbe a valid LaTeX font size e g tiny scriptsize footnotesize normalsize large Large LARGE huge Huge Global variable COREFFONT default value rm possible values string IATFX font name for printing coreferences Global variable COREFTABLE default value possible values assoc list Translation table for coreference numbers and corresponding full names strings numbers e g 1 subcat 2 phon 3 1 4 2 Global variable DOC HEADER default value documentstylearticle possible values string IATFX document style header Global variable MATHMODE default value displaymath possible values string TEX math mode for feature structures one of math displaymath equation Global variable TYPESTYLE default value infix possible values infixor prefix style for complex types infix or Lisp like prefix 52 5 USEFUL FUNCTIONS SWITCHES AND VARIABLES Global variable REMOVE TOPS default value nil possible values t or nil If t attributes with empty values and top type will be removed If ni1 top type attributes will not be remove
105. values t or nil This variable controls whether an automatic redraw is performed on the grapher when a type is re defined If nil no automatic redraw will be done Global variable NORMALFORM OPERATOR SYMBOL default value and possible values and or sor This variable contains the operator for the normal form of type expressions Either disjunctive or conjunctive normal form is possible Global variable TOP SYMBOL default value TOP possible values a symbol This variable contains the name for the top type of type hierarchies This is the default for the top keyword in the def domain function Global variable BOTTOM SYMBOL default value BOTTOM possible values a symbol This variable contains the name for the bottom type of type hierarchies This is the default for the top keyword in the defdomain function Itis also used for the generation of symbol names for bottom types Global variable TOP SORT default value SORT possible values a symbol This variable contains the name for the top sort of type hierarchies This is the default for the declaration of sorts if no super sort is specified 5 2 Setting Svvitches and Global Variables 31 Global variable LIST TYPE SYMBOL default value LIST possible values a symbol This variable contains the name for the first rest list type Global variable CONS TYPE SYMBOL default value CONS possible values a symbol This variable contains the name for the first rest
106. vironments and TDC statements An instance definition is similar to a type definition but instances are not part of the type hierarchy although they can inherit from types For instance each lexical entry will typically be an instance of a more general type e g intransitive verb type with additional specific graphemic and semantic information The idea is to keep the type lattice as small as possible The distinction between types and instances is similar to that of classes and instances in object oriented programming languages e g CLOS Instances are not inserted into the 7DE type hierarchy In general instances are objects feature structures which can be used by the parser It is possible to create several instances of the same type with different or the same instance specific information The general syntax of a TPC instance definition is instance name body 1 option body can be a complex description as in type definitions options in instance definitions are the optional keywords author doc date and status If the same name is given more than once for an instance of the same type the old instances will not be destroyed and the parser is responsible for the access to all instances This behavior can be controlled by the global variable ACCUMULATE INSTANCE DEFINITIONS 5For nonmonotonic definitions see section 4 6 17 4 10 Control Environment 27 If the status keyword is given the status value of the instance will be
107. vm The resulting feature structure after type expansion is o een null The only case where no disjunctive edges are introduced in the type hierarchy is a disjunction of pure atoms e g num 1 2 3 instead of means exclusive or Disjoint type partitions can be declared in the declare environment Section 4 5 4 6 10 Distributed Disjunctions A very useful feature of TDL implemented in the underlying unification system UP We is distributed or named disjunction Eisele amp D rre 90 This kind of disjunction has a specification restricted to a local domain although it may affect more than one attribute The main advantage of distributed disjunction is a more succinct representation Consider the following example season trigger spring summer fall winter 1 SEASON 1 NUMBER 1 PWN This structure has been generated by the following TDC expression season trigger SEASON 1 spring summer fall winter NUMBER 1 1 2 gt XP 4 FIG When a structure of type season trigger is unified with the structure SEASON summer fall the value of attribute NUMBER become 2 3 i e the value of attribute SEASON triggers the value of attribute NUMBER and vice versa The syntax of the alternative list in distributed disjunctions is Wa di where i is an integer number or a symbol the disjunction index for each group of distributed disjunctions 41 in the
108. x feature structure generated by 7DC2IAIEX is shown in figure 4 lt MY DOMAIN TYPE gt lgp count noun sem type label sort list first rest align attributes p nil coreftable 1 Sem 5 18 Printing Feature Structures 47 Optional Keyvvord Arguments latex options are the following optional keywords filename filename default value type gpi type lp instance gii or instance 1ii possible values string Unless filename is specified a filename will be computed from the type or instance name and the index 2 of the instance or global prototype The filename will be used to generate the TATEX output file filepath pathname default value value of variable FILEPATH possible values a string or a COMMON LISP path name pathname sets the directory in which the TATEX output file will be created and the shell command command will be executed The default for pathname is the tmp directory in the user s home directory hide types flag default value value of variable HIDE TYPES nil possible values tlnil If flag is nil types will be printed at the top of feature structures the top type will not be printed If flag is t types will not be printed The print mode options are described in section 7 remove tops flag default value value of REMOVE TOPS nil possible values tlnil If flag is t attributes with empty values i e values that unify with any value will not be printed If flag is
109. xpanded default prototype prototype of uvw partially expanded user defined prototype prototype of uvw Figure 2 Types skeletons prototypes and indices Type xyz s prototype is either unexpanded or contains no avm types Thus its prototypical feature structure is identical with its definition skeleton Type uvw has a fully expanded prototype and a user defined prototype which are both possibly partially expanded copies of uvw s skeleton feature structure USE CONJ HEURISTICS Their value can be set with set switch The global switch VERBOSE EXPANSION P can be set to t for verbose trace of type expansion Default value is nil quiet If some slots in local expand control are omitted they will be inferred from global expand control The syntax of expand control is as follows expand control C expand I type type index pred path expand only type type index pred path 5 delay ope type pred path V 2 maxdepth integer ask disj preference t ni1 attribute preference identifier use conj heuristics t ni1 use disj heuristics t ni1 expand function depth types first expand resolved predicate resolved p always false ignore global control t nil path gt identifier pattern identifier pattern pattern o identifier pred
110. y Grapher Application Domain Choose Exit Fegramed Latex Expand Inspect Type Top Node Backup Reset Print Graph TERNARY RULE c RULE UNARY RULE El LIST CONS TOP NULL AVM SORT DIFF LIST UNDEF BUILT IN STRING ATOM SYMBOL BIGNUM mo C FIXNUM Choose STRING Autoredraw on Autoredraw off Figure 5 TDL grapher Buttons Domain Select a domain out of a list of domain names Choose Choose a new node type out of a list of alphabetically sorted types This is the same a clicking the second mouse button at a highlighted type in the graph display The chosen node is called current node in the following lines e Exit Exit the Grapher process Fegramed Call FEGRAMED with the global prototype of the current node Latex Call Z7DC2IATEXwith the global prototype of the current node 55 Expand Call expand type on the global prototype of the current node Inspect Type Call the Inspector vvith the type info structure of the current node Top Node Redravv the graph vvith the current node as the nevv top node This is the same as pressing the Shift key and clicking the second mouse button Backup Redravv the graph vvith one of the super types of the current node as the nevv top node Reset Redravv the graph vvith the top node of the type hierarchy as the nevv top node Print Graph Print the graph to a PostScript file tdl graph ps Recompute

TDL A Type Description Language for HPSG Part 2

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