| { | |
| "paper_id": "E95-1025", | |
| "header": { | |
| "generated_with": "S2ORC 1.0.0", | |
| "date_generated": "2023-01-19T10:31:48.526714Z" | |
| }, | |
| "title": "ProFIT: Prolog with Features, Inheritance and Templates", | |
| "authors": [ | |
| { | |
| "first": "Gregor", | |
| "middle": [], | |
| "last": "Erbach", | |
| "suffix": "", | |
| "affiliation": { | |
| "laboratory": "", | |
| "institution": "Universit~t des Saarl~ndes Computerlinguistik", | |
| "location": { | |
| "postCode": "D-66041", | |
| "settlement": "Saarbrficken", | |
| "country": "Germany" | |
| } | |
| }, | |
| "email": "" | |
| } | |
| ], | |
| "year": "", | |
| "venue": null, | |
| "identifiers": {}, | |
| "abstract": "ProFIT is an extension of Standard Prolog with Features, Inheritance and Templates. ProFIT Mlows the programmer or grammar developer to declare an inheritance hierarchy, features and templates. Sorted feature terms can be used in ProFIT programs together with Prolog terms to provide a clearer description language for linguistic structures. ProFIT compiles all sorted feature terms into a Prolog term representation, so that the built-in Prolog term unification can be used for the unification of sorted feature structures, and no special unification algorithm is needed. ProFIT programs are compiled into Prolog programs, so that no meta-interpreter is needed for their execution. ProFIT thus provides a direct step from grammars developed with sorted feature terms to Prolog programs usable for practical NLP systems.", | |
| "pdf_parse": { | |
| "paper_id": "E95-1025", | |
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| "abstract": [ | |
| { | |
| "text": "ProFIT is an extension of Standard Prolog with Features, Inheritance and Templates. ProFIT Mlows the programmer or grammar developer to declare an inheritance hierarchy, features and templates. Sorted feature terms can be used in ProFIT programs together with Prolog terms to provide a clearer description language for linguistic structures. ProFIT compiles all sorted feature terms into a Prolog term representation, so that the built-in Prolog term unification can be used for the unification of sorted feature structures, and no special unification algorithm is needed. ProFIT programs are compiled into Prolog programs, so that no meta-interpreter is needed for their execution. ProFIT thus provides a direct step from grammars developed with sorted feature terms to Prolog programs usable for practical NLP systems.", | |
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| "section": "Abstract", | |
| "sec_num": null | |
| } | |
| ], | |
| "body_text": [ | |
| { | |
| "text": "There are two key ingredients for building an NLP system:", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "\u2022 a linguistic description \u2022 a processing model (parser, generator etc.) In the past decade, there have been diverging trends in the area of linguistic descriptions and in the area of processing models. Most large-scale linguistic descriptions make use of sorted feature formalisms, 1 but implementations of these formalisms are in general too slow for building practically usable NLP systems. Most of the progress in constructing efficient parsers and generators has been based on logic grammars that make use 1Sorted feature structures are sometimes referred to as typed feature structures, e.g. in Carpenter's \"Logic of Typed Feature Structures.\" We follow the usage in Logic Programming and the recent HPSG literature.", | |
| "cite_spans": [ | |
| { | |
| "start": 48, | |
| "end": 72, | |
| "text": "(parser, generator etc.)", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 601, | |
| "end": 612, | |
| "text": "Carpenter's", | |
| "ref_id": null | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "of ordinary prblog terms. We provide a general tool that brings together these developments by compiling sorted feature terms into a Prolog term representation, so that techniques from logic programming and logic grammars can be used to provide efficient processing models for sorted feature grammars.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "In this introductory section, we discuss the advantages of sorted feature formalisms, and of the logic grammar paradigm, and show how the two developments can be combined. The following sections describe the ProFIT language which provides sorted feature terms for Prolog, and its implementation.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Introduction", | |
| "sec_num": "1" | |
| }, | |
| { | |
| "text": "Feature Formalisms Sorted feature formalisms are often used for the development of large-coverage grammars, because they are very well suited for a structured description of complex linguistic data. Sorted feature terms have several advantages over Prolog terms as a representation langauge.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "1. They provide a compact notation. Features that are not instantiated can be omitted; there is no need for anonymous variables.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "2. Features names are mnemonic, argument positions are not.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "3. Adding a new feature to a sort requires one change in a declaration, whereas adding an argument to a Prolog functor requires changes (mostly insertion of anonymous variables) to every occurence of the functor.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "4. Specification of the subsort relationship is more convenient than constructing Prolog terms which mirror these subsumption relationships.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "Implementations of sorted feature formalisms such as TDL (Krieger and Sch~ifer, 1994) , ALE (Carpenter, 1993) , CUF (DSrre and Dorna, 1993) , TFS (Emele and Zajac, 1990) and others have been used successfully for the development and testing of large grammars and lexicons, but they may be too slow for actual use in applications because they are generally built on top of Prolog or LISP, and can therefore not be as efficient as the built-in unification of Prolog. There are a few logic programming langauges, such as LIFE (Ait-Kaci and Lincoln, 1989) or Oz (Smolka et al., 1995) , that provide sorted feature terms, but no commercial implementations of these languages with efficient compilers are yet available.", | |
| "cite_spans": [ | |
| { | |
| "start": 57, | |
| "end": 85, | |
| "text": "(Krieger and Sch~ifer, 1994)", | |
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| }, | |
| { | |
| "start": 92, | |
| "end": 109, | |
| "text": "(Carpenter, 1993)", | |
| "ref_id": "BIBREF5" | |
| }, | |
| { | |
| "start": 112, | |
| "end": 139, | |
| "text": "CUF (DSrre and Dorna, 1993)", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 142, | |
| "end": 169, | |
| "text": "TFS (Emele and Zajac, 1990)", | |
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| }, | |
| { | |
| "start": 523, | |
| "end": 551, | |
| "text": "(Ait-Kaci and Lincoln, 1989)", | |
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| }, | |
| { | |
| "start": 558, | |
| "end": 579, | |
| "text": "(Smolka et al., 1995)", | |
| "ref_id": "BIBREF20" | |
| } | |
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| "section": "Grammar Development in Sorted", | |
| "sec_num": "1.1" | |
| }, | |
| { | |
| "text": "Much work on efficient processing algorithms has been done in the logic grammar framework. This includes work on", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Efficient Processing based on Logic Grammars", | |
| "sec_num": "1.2" | |
| }, | |
| { | |
| "text": "\u2022 Compiling grammars into efficient parsers and generators: compilation of DCGs into (top-down) Prolog programs, left-corner parsers (BUP), LR parsers, head-corner parsers, and semantic-head driven generators.", | |
| "cite_spans": [], | |
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| "section": "Efficient Processing based on Logic Grammars", | |
| "sec_num": "1.2" | |
| }, | |
| { | |
| "text": "\u2022 Use of recta-programming for self-monitoring to ensure generation of unambiguous utterances (Neumann and van Noord, 1992) \u2022 Work in the area of Explanation-Based Learning (EBL) to learn frequently used' structures (Samuelsson, 1994) \u2022 Tabulation techniques, from the use of wellformed substring tables to the latest developments in Earley deduction, and memoing techniques for logic programming (Neumann, 1994) \u2022 Work based on Constraint Logic Programming (CLP) to provide processing models for principle-based grammars (Matiasek, 1994) \u2022 Using coroutining (dif, freeze etc.) to provide more efficient processing models", | |
| "cite_spans": [ | |
| { | |
| "start": 94, | |
| "end": 123, | |
| "text": "(Neumann and van Noord, 1992)", | |
| "ref_id": "BIBREF17" | |
| }, | |
| { | |
| "start": 216, | |
| "end": 234, | |
| "text": "(Samuelsson, 1994)", | |
| "ref_id": "BIBREF18" | |
| }, | |
| { | |
| "start": 397, | |
| "end": 412, | |
| "text": "(Neumann, 1994)", | |
| "ref_id": "BIBREF17" | |
| }, | |
| { | |
| "start": 522, | |
| "end": 538, | |
| "text": "(Matiasek, 1994)", | |
| "ref_id": "BIBREF14" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Efficient Processing based on Logic Grammars", | |
| "sec_num": "1.2" | |
| }, | |
| { | |
| "text": "\u2022 Partial deduction techniques to produce more efficient grammars \u2022 Using Prolog and its indexing facilities to build up a lexicon database", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Efficient Processing based on Logic Grammars", | |
| "sec_num": "1.2" | |
| }, | |
| { | |
| "text": "Since much of this work involves compilation of grammars into Prolog programs, such programs can immediately benefit from any improvements in Prolog compilers (for example the tabulation provided by XSB Prolog can provide a more efficient implementation of charts) which makes the grammars more usable for NLP systems.", | |
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| "ref_spans": [], | |
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| "section": "Efficient Processing based on Logic Grammars", | |
| "sec_num": "1.2" | |
| }, | |
| { | |
| "text": "Sorted Feature Formalisms It has been noted that first-order Prolog terms provide the equivalent expressive power as sorted feature terms (Mellish, 1992) .", | |
| "cite_spans": [ | |
| { | |
| "start": 138, | |
| "end": 153, | |
| "text": "(Mellish, 1992)", | |
| "ref_id": "BIBREF16" | |
| } | |
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| "section": "Combining Logic Grammars and", | |
| "sec_num": "1.3" | |
| }, | |
| { | |
| "text": "For example, Carpenter's typed feature structures (Carpenter, 1992) can easily be represented as Prolog terms, if the restriction is given up that the sort hierarchy be a bounded complete partial order. Such compilation of sorted feature terms into Prolog terms has been successfully used in the Core Language Engine (CLE) (Alshawi, 1991) and in the Advanced Linguistic Engineering Platform (ALEP), (Alshawi et al., 1991) . 2 ProFIT extends the compilation techniques of these systems through the handling of multi-dimensional inheritance (Erbach, 1994) , and makes them generally available for a wide range of applications by translating programs (or grammars) with sorted feature terms into Prolog programs.", | |
| "cite_spans": [ | |
| { | |
| "start": 50, | |
| "end": 67, | |
| "text": "(Carpenter, 1992)", | |
| "ref_id": "BIBREF4" | |
| }, | |
| { | |
| "start": 323, | |
| "end": 338, | |
| "text": "(Alshawi, 1991)", | |
| "ref_id": "BIBREF1" | |
| }, | |
| { | |
| "start": 399, | |
| "end": 421, | |
| "text": "(Alshawi et al., 1991)", | |
| "ref_id": "BIBREF1" | |
| }, | |
| { | |
| "start": 539, | |
| "end": 553, | |
| "text": "(Erbach, 1994)", | |
| "ref_id": "BIBREF8" | |
| } | |
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| "section": "Combining Logic Grammars and", | |
| "sec_num": "1.3" | |
| }, | |
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| "text": "ProFIT is not a grammar formalism, but rather extends any grammar formalism in the logic grammar tradition with the expressive power of sorted feature terms. Super > [Sub, , ..., (1) It is also possible to provide subsorts that are not mutually exclusive, as in (2), where one subsort may be chosen from each of the \"dimensions\" connected by the * operator (Erbach, 1994) .", | |
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| "start": 166, | |
| "end": 171, | |
| "text": "[Sub,", | |
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| "start": 172, | |
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| "text": ",", | |
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| "start": 174, | |
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| "text": "...,", | |
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| "start": 179, | |
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| "text": "(1)", | |
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| { | |
| "start": 357, | |
| "end": 371, | |
| "text": "(Erbach, 1994)", | |
| "ref_id": "BIBREF8" | |
| } | |
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| "section": "Combining Logic Grammars and", | |
| "sec_num": "1.3" | |
| }, | |
| { | |
| "text": "Super > [Subl.l,...,Subl.n ", | |
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| { | |
| "start": 8, | |
| "end": 26, | |
| "text": "[Subl.l,...,Subl.n", | |
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| "section": "Combining Logic Grammars and", | |
| "sec_num": "1.3" | |
| }, | |
| { | |
| "text": "(2) [Subk.l,..., Subk.m] Every sort must only be defined once, i.e. it can appear only once on the left-hand side of the connective >.", | |
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| { | |
| "start": 4, | |
| "end": 24, | |
| "text": "[Subk.l,..., Subk.m]", | |
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| "section": "] * :", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "2Similar, but less efficient compilation schemes are used in Hirsh's P-PATR (Hirsh, 1986) and Covington's GULP system (Covington, 1989) .", | |
| "cite_spans": [ | |
| { | |
| "start": 76, | |
| "end": 89, | |
| "text": "(Hirsh, 1986)", | |
| "ref_id": "BIBREF9" | |
| }, | |
| { | |
| "start": 118, | |
| "end": 135, | |
| "text": "(Covington, 1989)", | |
| "ref_id": "BIBREF6" | |
| } | |
| ], | |
| "ref_spans": [], | |
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| "section": "] * :", | |
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| "text": "The sort hierarchy must not contain any cycles, i.e. there must be no sorts A and B, such that A#B, andA> B> A.", | |
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| "section": "] * :", | |
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| "text": "The immediate subsorts of top can be declared to be extensional. Two terms which are of an extensional sort are only identical if they.have a most specific sort (which has no subsort), and if all features are instantiated to ground terms. If a sort is not declared as extensional, it is intensional. Two intensional terms are identical only if they have been unified.", | |
| "cite_spans": [], | |
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| "section": "] * :", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "Unlike unsorted feature formalisms (such as PATR-II), where any feature can be added to any structure, ProFIT follows the notion of appropriateness in Carpenter's logic of typed feature structures (Carpenter, 1992) , and introduces features for particular sorts. For each sort, one must declare which features are introduced by it. The features introduced by a sort are inherited by all its subsorts, which may also introduce additional features. A feature must be introduced only at one most general sort. This makes it possible to provide a notation in which the sort name can be omitted since it can be inferred from the use of a feature that is appropriate for that sort.", | |
| "cite_spans": [ | |
| { | |
| "start": 197, | |
| "end": 214, | |
| "text": "(Carpenter, 1992)", | |
| "ref_id": "BIBREF4" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "This notion of appropriateness is desirable for structuring linguistic knowledge, as it prevents the ad-hoc introduction of features, and requires a careful design of the sort and feature hierarchy. Appropriateness is also a prerequisite for compilation of feature terms into fixed-arity Prolog terms.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "Each feature has a sortal restriction for its value. If a feature's value is only restricted to be of sort top, then the sortal restriction can be omitted. The syntax of feature declarations is given in", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "(3). Sort intro [Feature1 : Restrl, :", | |
| "cite_spans": [], | |
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| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "(3)", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "Feature, : Restrn].", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "The following declaration defines a sort bi-nary_tree with subsorts leaf and internaLnode. The sort binary tree introduces the feature label and its subsort adds the features lefl_daughler and right_daughter. If a sort has subsorts and introduces features, these are combined in one declaration. ", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Declarations", | |
| "sec_num": "2.2" | |
| }, | |
| { | |
| "text": "On the basis of the declarations, sorted feature terms can be used in definite clauses in addition to and in combination with Prolog terms. A Prolog term can have a feature term as its argument, and a feature can have a Prolog term as its value. This avoids potential interface problems between different representations, since terms do not have to be translated between different languages. As an example, semantic representations in first-order terms can be used as feature values, but do not need to be encoded as feature terms. Sorted feature terms consist of a specification of the sort of the term (4), or the specification of a feature value (5), or a conjunction of terms (6). A complete BNF of all ProFIT terms is given in the appendix.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "< Sort (4) Feature ! Value (5) Term ~ Term (6)", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "The following clauses (based on HPSG) state that a structure is saturated if its subcat value is the empty list, and that a structure satisfies the Head Feature Principle (hfp) if its head features are identical with the head features of its head daughter. 3 Note that these clauses provide a concise notation because uninstantiated features can be omitted, and the sorts of structures do not have to be specified explicitly because they can be infered from use of the features.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "saturated ( synsem ! local ! cat ! subcat ! <elist ).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "hfp ( synsem ! local ! cat ! head ! X dtrs ! head_dr r ! synsem ! local ! cat ! head ! X ).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "Note that conjunction also provides the possiblity to tag a Prolog term or feature term with a variable (Var ~ Term).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sorted Feature Terms", | |
| "sec_num": "2.3" | |
| }, | |
| { | |
| "text": "In the organisation of linguistic knowledge, feature structures are often deeply embedded, due to the need to group together sets of features whose value can be structure-shared. In the course of grammar development, it is often necessary to change the \"location\" of a feature in order to get the right structuring of information.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "Such a change of the '~feature geometry\" makes it necessary to change the path in all references to a feature. This is often done by introducing templates whose sole purpose is the abbreviation of a path to a feature.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "ProFIT provides a mechanism to search for paths to features automatically provided that the sortal restrictions for the feature values are strong enough to ensure that there is a unique minimal path. A path is minimal if it does not contain any repeated features or sorts.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "3These clauses assume appropriate declarations for the sort elist, and for the features synsem, local, cat, subcat, head, dtrs and head_dtr.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "The sort from which to start the feature search must either be specified explicitly (7) or implicitly given through the sortal restriction of a feature value, in which case the sort can be omitted and the expression (8) can be used.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "Sort >>> Feature ! Term (7)", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": ">>> Feature ! Term", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "The following clause makes use of feature search to express the Head Feature Principle (hfp).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "hfp( sign>>>head !X dtrs!head_dtr} >>>head!X ).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "While this abbreviation for feature paths is new for formal description languages, similar abbreviatory conventions are often used in linguistic publications. They are easily and unambiguously understood if there is only one unique path to the feature which is not embedded in another structure of the same sort.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Feature Search", | |
| "sec_num": "2.4" | |
| }, | |
| { | |
| "text": "The purpose of templates is to give names to frequently used structures. In addition to being an abbreviatory device, the template mechanism serves three other purposes.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "\u2022 Abstraction and interfacing by providing a fixed name for a value that may change,", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "\u2022 Partial evaluation, \u2022 Functional notation that can make specifications easier to understand. Templates are defined by expressions of the form (9), where Name and Value can be arbitrary ProFIT terms, including variables, and template calls. There can be several template definitions with the same name on the left-hand side (relational templates). Since templates are expanded at compile time, template definitions must not be recursive.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "EQUATION", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [ | |
| { | |
| "start": 0, | |
| "end": 8, | |
| "text": "EQUATION", | |
| "ref_id": "EQREF", | |
| "raw_str": "Name := Value,", | |
| "eq_num": "(9)" | |
| } | |
| ], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "Templates are called by using the template name prefixed with \u00a9 in a ProFIT term.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "Abstraction makes it possible to change data structures by changing their definition only at one point. Abstraction also ensures that databases (e.g. lexicons) which make use of these abstractions can be re-used in \"different kinds of applications where different datastructures represent these abstractions.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "Abstraction through templates is also useful for defining interfaces between grammars and processing modules. If semantic processing must access the semantic representations of different grammars, this can be done if the semantic module makes use of a template defined for each grammar that indicates where in the feature structure the semantic information is located, as in the following example for HPSG. Partial evaluation is achieved when a structure (say a principle of a grammar) is represented by a template that gets expanded at compile time, and does not have to be called as a goal during processing.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "We show the use of templates for providing functional notation by a simple example, in which the expression \u00a9first(X) stands for the first element of list X, and ~rest(X) stands for the tail of list X, as defined by the following template definition. The member relation can be defined with the following clauses, which correspond very closely to the natural-language statement of the member relation given as comments. Note that expansion of the templates yields the usual definition of the member relation in Prolog.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "Y, The first element of a list ~, is a member of the list. member (@first (List), List).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "~, Element is a member of a list Y, if it is a member of the rest of the list member(Element,List) :member (Element, @rest (List)).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "The expressive power of an n-place template is the same as that of an n+l place fact.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Templates", | |
| "sec_num": "2.5" | |
| }, | |
| { | |
| "text": "Disjunction in the general case cannot be encoded in a Prolog term representation. 4 Since a general treatment of disjunction would involve too much computational overhead, we provide disjunctive terms only as syntactic sugar. Clauses containing disjunctive terms are compiled to several clauses, one for each consistent combination of disjuncts. Disjunctive terms make it possible to state facts that belong together in one clause, as the following formulation of the Semantics Principle (s em_p) of HPSG, which states that the content value of a head-adjunct structure is the content value of the adjunct daughter, and the content value of the other headed structures (head-complement, headmarker, and head-filler structure) is the content value of the head daughter. ).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Disjunction", | |
| "sec_num": "2.6" | |
| }, | |
| { | |
| "text": "For disjunctions of atoms, there exists a Prolog term representation, which is described below. 4see the complexity analysis by Brew (Brew, 1991) .", | |
| "cite_spans": [ | |
| { | |
| "start": 133, | |
| "end": 145, | |
| "text": "(Brew, 1991)", | |
| "ref_id": "BIBREF3" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Disjunction", | |
| "sec_num": "2.6" | |
| }, | |
| { | |
| "text": "For domains involving only a finite set of atoms as possible values, it is possible to provide a Prolog term representation (due to Colmerauer, and described by Mellish (Mellish, 1988) ) to encode any subset of the possible values in one term.", | |
| "cite_spans": [ | |
| { | |
| "start": 169, | |
| "end": 184, | |
| "text": "(Mellish, 1988)", | |
| "ref_id": "BIBREF15" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Finite Domains", | |
| "sec_num": "2.7" | |
| }, | |
| { | |
| "text": "Consider the agreement features person (with values 1, 2 and 3) and number (with values sg and pl). For the two features together there are six possible combinations of values (l&;sg, 2&sg, 3&sg, l&pl, 2&pl, 3&pl) . Any subset of this set of possible values can be encoded as one Prolog term. The following example shows the declaration needed for this finite domain, and some clauses that refer to subsets of the possible agreement values by making use of the logical connectives \" (negation), & (conjunction), or (disjunction).5 agr fin_dom [1, 2, 3] This kind of encoding is only applicable to domains which have no coreferences reaching into them, in the example only the agreement features as a whole can be coreferent with other agreement features, but not the values of person or number in isolation. This kind of encoding is useful to avoid the creation of choice points for the lexicon of languages where one inflectional form may correspond to different feature values.", | |
| "cite_spans": [ | |
| { | |
| "start": 176, | |
| "end": 213, | |
| "text": "(l&;sg, 2&sg, 3&sg, l&pl, 2&pl, 3&pl)", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 543, | |
| "end": 546, | |
| "text": "[1,", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 547, | |
| "end": 549, | |
| "text": "2,", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 550, | |
| "end": 552, | |
| "text": "3]", | |
| "ref_id": null | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Finite Domains", | |
| "sec_num": "2.7" | |
| }, | |
| { | |
| "text": "Unlike Prolog, the concrete syntax of ProFIT allows to write down cyclic terms by making use of conjunction:", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "x & ~(x). Cyclic terms constitute no longer a theoretical or practical problem in logic programming, and almost all modern Prolog implementations can perform their unification (although they can't print them out). Cyclic terms arise naturally in NLP through unification of non-cyclic terms, e.g., the Subcategorization Principle and the Spec Principle of HPSG.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "ProFIT supports cyclic terms by being able to print them out as solutions. In order to do this, SThe syntax for finite domain terms is Terra,Domain. However, when atoms from a finite domains are combined by the conjunction, disjunction and negation connectives, the specification of the domain can be omitted. In the example, the domain must only be specified for the value 2, which could otherwise be confused with the integer 2. the dreaded occur check must be performed. Since this must be done only when results are printed out as ProFIT terms, it does not affect the runtime performance.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "3 From ProFIT terms to Prolog terms 3.1 Compilation of Sorted Feature Terms The compilation of sorted feature terms into a Prolog term representation is based on the following principles, which are explained in more detail in (Mellish, 1988; Mellish, 1992; Schgter, 1993; Erbach, 1994 ).", | |
| "cite_spans": [ | |
| { | |
| "start": 226, | |
| "end": 241, | |
| "text": "(Mellish, 1988;", | |
| "ref_id": "BIBREF15" | |
| }, | |
| { | |
| "start": 242, | |
| "end": 256, | |
| "text": "Mellish, 1992;", | |
| "ref_id": "BIBREF16" | |
| }, | |
| { | |
| "start": 257, | |
| "end": 271, | |
| "text": "Schgter, 1993;", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 272, | |
| "end": 284, | |
| "text": "Erbach, 1994", | |
| "ref_id": "BIBREF8" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "\u2022 The Prolog representation of a sort is an instance of the Prolog representation of its supersorts.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "\u2022 Features are represented by arguments. If a feature is introduced by a subsort, then the argument is added to the term that further instantiates its supersort.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "\u2022 Mutually exclusive sorts have different functots at the same argument position, so that their unification fails.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "We illustrate these principles for compiling sorted feature terms into Prolog terms with an example from aPse. The following declaration states that the sort sign has two mutually exclusive subsorts lexical and phrasal and introduces four features. sign > [lexical,phrasal] intro [phon, synsem, qstore, retrieved] .", | |
| "cite_spans": [ | |
| { | |
| "start": 256, | |
| "end": 273, | |
| "text": "[lexical,phrasal]", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 280, | |
| "end": 313, | |
| "text": "[phon, synsem, qstore, retrieved]", | |
| "ref_id": null | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "In the corresponding Prolog term representation below, the first argument is a variable whose only purpose is being able to test whether two terms are coreferent or whether they just happen to have the same sort and the same values for all features. In case of extensional sorts (see section 2.1), this variable is omitted. The second argument can be further instantiated for the subsorts, and the remaining four arguments correspond to the four features.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "$s ign (Var, LexPhras, Phon, Synsem, qstore, Retriev)", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "The following declaration introduces two sort hierarchy \"dimensions\" for subsorts of phrasal, and one new feature. The corresponding Prolog term representation instantiates the representation for the sort sign further, and leaves argument positions that can be instantiated further by the subsorts of phrasal, and for the newly introduced feature daughters.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "phrasal > [headed,non_headed] * [decl,int,rel] intro [daughters] .", | |
| "cite_spans": [ | |
| { | |
| "start": 32, | |
| "end": 46, | |
| "text": "[decl,int,rel]", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 53, | |
| "end": 64, | |
| "text": "[daughters]", | |
| "ref_id": null | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "$sign(yar, $phrasal(Phrasesort,Clausesort,Dtrs),", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "Phon, Synsem, Qstore, Retrieved)", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Cyclic Terms", | |
| "sec_num": "2.8" | |
| }, | |
| { | |
| "text": "The compilation of finite domains into Prolog terms is performed by the \"brute-force\" method described in (Mellish, 1988) . A finite domain with n possible domain elements is represented by a Prolog term with n + 1 arguments. Each domain element is associated with a pair of adjacent arguments. For example, the agreement domain agr from section 2.7 with its six elements (l&sg, 2&sg, 3&sg, l~:pl, 2~:pl, 3&pl) is represented by a Prolog term with seven arguments.", | |
| "cite_spans": [ | |
| { | |
| "start": 106, | |
| "end": 121, | |
| "text": "(Mellish, 1988)", | |
| "ref_id": "BIBREF15" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Compilation of Finite Domains", | |
| "sec_num": "3.2" | |
| }, | |
| { | |
| "text": "Note that the first and last argument must be different. In the example, this is achieved by instantiation with different atoms, but an inequality constraint (Prolog I['s dif) would serve the same purpose. We assume that the domain element l~zsg corresponds to the first and second arguments, 2&sg to the second and third arguemnts, and so on, as illustrated below.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sagr(1,A,B,C,D,E,O)", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "Sagr ( 1 , h , B , C , D , E , 0 ) lsg 2sg 3sg lpl 2pl 3pl A domain description is translated into a Prolog term by unifying the argument pairs that are excluded by the description. For example, the domain description 2 or pl excludes l&sg and 3&sg, so that the the first and second argument are unified (l~sg), as well as the third and fourth (3&sg). $agr(1,1,X,X,D,E,0) When two such Prolog terms are unified, the union of their excluded elements is computed by unificatation, or conversely the intersection of the elements which are in the domain description. The unification of two finite domain terms is successful as long as they have at least one element in common. When two terms are unified which have no element in common, i.e., they exclude all domain elements, then unification fails because all arguments become unified with each other, including the first and last arguments, which are different.", | |
| "cite_spans": [ | |
| { | |
| "start": 5, | |
| "end": 34, | |
| "text": "( 1 , h , B , C , D , E , 0 )", | |
| "ref_id": null | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Sagr(1,A,B,C,D,E,O)", | |
| "sec_num": null | |
| }, | |
| { | |
| "text": "ProFIT has been implemented in Quintus and Sicstus Prolog, and should run with any Prolog that conforms to or extends the proposed ISO Prolog standard.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "All facilities needed for the development of application programs, for example the module system and declarations (dynamic, multifile etc.) are supported by ProFIT.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "Compilation of a ProFIT file generates two kinds of files as output.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "1. Declaration files that contain information for compilation, derived from the declarations.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "2. A program file (a Prolog program) that contains the clauses, with all ProFIT terms compiled into their Pro]og term representation.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "The program file is compiled on the basis of the declaration files. If the input and output of the program (the exported predicates of a module) only make use of Prolog terms, and feature terms are only used for internal purposes, then the program file is all that is needed. This is for example the case with a grammar that uses feature terms for grammatical description, but whose input and output (e.g. graphemic form and logical form) are represented as normal Prolog terms.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "Declarations and clauses can come in any order in a ProFIT file, so that the declarations can be written next to the clauses that make use of them. Declarations, templates and clauses can be distributed across several files, so that it becomes possible to modify clauses without having to recompile the declarations, or to make changes to parts of the sort hierarchy without having to recompile the entire hierarchy.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "Sort checking can be turned off for debugging purposes, and feature search and handling of cyclic terms can be turned off in order to speed up the compilation process if they are not needed.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "Error handling is currently being improved to give informative and helpful warnings in case of undefined sorts, features and templates, or cyclic sort hierarchies or template definitions.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "For the development of ProFIT programs and grammars, it is necessary to give input and output and debugging information in ProFIT terms, since the Pro]og term representation is not very readable. ProFIT provides a user interface which * accepts queries containing ProFIT terms, and translates them into Prolog queries,", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "\u2022 converts the solutions to the Prolog query back into ProFIT terms before printing them out,", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "\u2022 prints out debugging information as ProFIT terms.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
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| "sec_num": "4" | |
| }, | |
| { | |
| "text": "When a solution or debugging information is printed out, uninstantiated features are omitted, and shared structures are printed only once and represented by variables on subsequent occurences.", | |
| "cite_spans": [], | |
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| "sec_num": "4" | |
| }, | |
| { | |
| "text": "A pretty-printer is provided that produces a neatly formatted screen output of ProFIT terms, and is configurable by the user. ProFIT terms can also be output in IATEX format, and an interface to the graphical feature editor Fegramed is foreseen.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
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| "sec_num": "4" | |
| }, | |
| { | |
| "text": "In order to give a rough idea of the efficiency gains of a compilation into Prolog terms instead of using a feature term unification algorithm implemented on top of Prolog, we have compared the runtimes with ALE and the Eisele-DSrre algorithm for unsorted feature unification for the following tasks: (i) unification of (unsorted) feature structures, (ii) unification of inconsistent feature structures (unification failure), (iii) unification of sorts, (iv) lookup of one of I0000 feature structures (e.g. lexical items), (v) parsing with an HPSG grammar to provide a mix of the above tasks.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
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| "sec_num": "4" | |
| }, | |
| { | |
| "text": "The timings obtained so far indicate that ProFIT is 5 to 10 times faster than a system which in~plements a unification algorithm on top of Prolog, a result which is predicted by the studies of SchSter (SchSter, 1993) and the experience of the Core Language Engine.", | |
| "cite_spans": [ | |
| { | |
| "start": 201, | |
| "end": 216, | |
| "text": "(SchSter, 1993)", | |
| "ref_id": "BIBREF19" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "The ProFIT system and documentation are available free of charge by anonymous ftp (server: ftp.coli.uni-sb.de, directory: pub/profit).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Implementation", | |
| "sec_num": "4" | |
| }, | |
| { | |
| "text": "ProFIT allows the use of sorted feature terms in Prolog programs and Logic Grammars without sacrificing the efficiency of Prolog's term unification. It is very likely that the most efficient commercial Prolog systems, which provide a basis for the implementation of NLP systems, will conform to the proposed ISO standard. Since the ISO standard includes neither inheritance hierarchies nor feature terms (which are indispensible for the development of large grammars, lexicons and knowledge bases for NLP systems), a tool like ProFIT that compiles sorted feature terms into Prolog terms is useful for the development of grammars and lexicons that can be used for applications. ProFIT is not a grammar formalism, but rather aims to extend current and future formalisms and processing models in the logic grammar tradition with the expressive power of sorted feature terms. Since the output of ProFIT compilation are Prolog programs, all the techniques developed for the optimisation of logic programs (partial evaluation, tabulation, indexing, program transformation techniques etc.) can be applied straightforwardly to improve the performance of sorted feature grammars.", | |
| "cite_spans": [], | |
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| "eq_spans": [], | |
| "section": "Conclusion", | |
| "sec_num": "5" | |
| }, | |
| { | |
| "text": "This work was supported by", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Acknowledgements", | |
| "sec_num": "6" | |
| }, | |
| { | |
| "text": "\u2022 The Commission of the European Communities through the project LRE-61-061 \"Reusable Gratnmatical Resources\", where it has been (ab-)used in creative ways to prototype extensions for the ALEP formalism such as set descriptions, linear precedence con-straints and guarded constraints (Manandhat, 1994; Manandhar, 1995) .", | |
| "cite_spans": [ | |
| { | |
| "start": 284, | |
| "end": 301, | |
| "text": "(Manandhat, 1994;", | |
| "ref_id": null | |
| }, | |
| { | |
| "start": 302, | |
| "end": 318, | |
| "text": "Manandhar, 1995)", | |
| "ref_id": "BIBREF13" | |
| } | |
| ], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Acknowledgements", | |
| "sec_num": "6" | |
| }, | |
| { | |
| "text": "* Deutsche Forschungsgemeinschaft, Special Research Division 314 \"Artificial Intelligence -Knowledge-Based Systems\" through project N3 \"Bidirectional Linguistic Deduction\" (BiLD), where it is used to compile typed feature grammars into logic grammars, for which bidirectional NLP algorithms are developed, and", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Acknowledgements", | |
| "sec_num": "6" | |
| }, | |
| { | |
| "text": "\u2022 Cray Systems (formerly PE-Luxembourg), with whom we had fruitful interaction concerning the future development of the ALEP system-.", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Acknowledgements", | |
| "sec_num": "6" | |
| }, | |
| { | |
| "text": "Some code for handling of finite domains was adapted from a program by Gertjan van Noord. Wojciech Skut and Christian Braun were a great help in testing and improving the system. Thanks to all the early users and ~-testers for discovering bugs and inconsistencies, and for providing feedback and encouragement. Special thanks for service with a smiley :-).", | |
| "cite_spans": [], | |
| "ref_spans": [], | |
| "eq_spans": [], | |
| "section": "Acknowledgements", | |
| "sec_num": "6" | |
| } | |
| ], | |
| "back_matter": [], | |
| "bib_entries": { | |
| "BIBREF0": { | |
| "ref_id": "b0", | |
| "title": "Life, a naturM language for natural language", | |
| "authors": [ | |
| { | |
| "first": "Patrick", | |
| "middle": [], | |
| "last": "Hassan A'it-Kaci", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "", | |
| "middle": [], | |
| "last": "Lincoln", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1989, | |
| "venue": "T. A. Informations", | |
| "volume": "30", | |
| "issue": "1-2", | |
| "pages": "37--67", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Hassan A'it-Kaci and Patrick Lincoln. 1989. Life, a naturM language for natural language. T. A. Informations, 30(1-2):37 -67.", | |
| "links": null | |
| }, | |
| "BIBREF1": { | |
| "ref_id": "b1", | |
| "title": "Eurotra 6/1: Rule for-mMism and virtual machine design study --Final report", | |
| "authors": [ | |
| { | |
| "first": "H", | |
| "middle": [], | |
| "last": "Alshawi", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "D", | |
| "middle": [ | |
| "J" | |
| ], | |
| "last": "Arnold", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "R", | |
| "middle": [], | |
| "last": "Backofen", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "D", | |
| "middle": [ | |
| "M" | |
| ], | |
| "last": "Carter", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "J", | |
| "middle": [], | |
| "last": "Lindop", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "K", | |
| "middle": [], | |
| "last": "Netter", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": ":", | |
| "middle": [ | |
| "I" | |
| ], | |
| "last": "Tsujii", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "H", | |
| "middle": [], | |
| "last": "Uszkoreit", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1991, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "H. Alshawi, D. J. Arnold, R. Backofen, D. M. Carter, J. Lindop, K. Netter, :I. Tsujii, and H. Uszkoreit. 1991. Eurotra 6/1: Rule for- mMism and virtual machine design study --Fi- nal report. Technical report, SRI International, Cambridge.", | |
| "links": null | |
| }, | |
| "BIBREF2": { | |
| "ref_id": "b2", | |
| "title": "The Core Language Engine", | |
| "authors": [], | |
| "year": 1991, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Hiyan Alshawi, editor. 1991. The Core Language Engine. MIT Press.", | |
| "links": null | |
| }, | |
| "BIBREF3": { | |
| "ref_id": "b3", | |
| "title": "Systemic classification and its efficiency", | |
| "authors": [ | |
| { | |
| "first": "Chris", | |
| "middle": [], | |
| "last": "Brew", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1991, | |
| "venue": "Computational Linguistics", | |
| "volume": "17", | |
| "issue": "4", | |
| "pages": "375--408", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Chris Brew. 1991. Systemic classification and its efficiency. Computational Linguistics, 17(4):375 -408.", | |
| "links": null | |
| }, | |
| "BIBREF4": { | |
| "ref_id": "b4", | |
| "title": "The logic of typed feature structures. Cambridge Tracts in Theoretical Computer Science", | |
| "authors": [ | |
| { | |
| "first": "Bob", | |
| "middle": [], | |
| "last": "Carpenter", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1992, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Bob Carpenter. 1992. The logic of typed feature structures. Cambridge Tracts in Theoretical Computer Science. Cambridge University Press, Cambridge.", | |
| "links": null | |
| }, | |
| "BIBREF5": { | |
| "ref_id": "b5", | |
| "title": "ALE Version ~: User Manual", | |
| "authors": [ | |
| { | |
| "first": "Bob", | |
| "middle": [], | |
| "last": "Carpenter", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1993, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Bob Carpenter, 1993. ALE Version ~: User Man- ual. University of Pittsburgh.", | |
| "links": null | |
| }, | |
| "BIBREF6": { | |
| "ref_id": "b6", | |
| "title": "GULP 2.0: an extension of Prolog for unification-based grammar", | |
| "authors": [ | |
| { | |
| "first": "Michael", | |
| "middle": [], | |
| "last": "Covington", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1989, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Michael Covington. 1989. GULP 2.0: an exten- sion of Prolog for unification-based grammar. Technical Report AI-1989-01, Advanced Com- putational Methods Center, University of Geor- gia.", | |
| "links": null | |
| }, | |
| "BIBREF7": { | |
| "ref_id": "b7", | |
| "title": "Computational Aspects of Constraint-Based Linguistic Description. Deliverable RI.P.A. DYANA-2 -ESPRIT Basic Research Project 6852. unification grammars", | |
| "authors": [ | |
| { | |
| "first": "Jochen", | |
| "middle": [], | |
| "last": "Dlrre", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "Michael", | |
| "middle": [], | |
| "last": "Dorna", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1993, | |
| "venue": "Proceedings of the 13th International Conference on Computational Linguistics", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Jochen DLrre and Michael Dorna. 1993. CUF - A formalism for linguistic knowledge represen- tation. In Jochen DLrre, editor, Computational Aspects of Constraint-Based Linguistic Descrip- tion. Deliverable RI.P.A. DYANA-2 -ESPRIT Basic Research Project 6852. unification grammars. In Proceedings of the 13th International Conference on Computa- tional Linguistics, Helsinki.", | |
| "links": null | |
| }, | |
| "BIBREF8": { | |
| "ref_id": "b8", | |
| "title": "Multi-dimensional inheritance", | |
| "authors": [ | |
| { | |
| "first": "Gregor", | |
| "middle": [], | |
| "last": "Erbach", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1994, | |
| "venue": "Proceedings of KON-VENS '9.~", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "102--111", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Gregor Erbach. 1994. Multi-dimensional inheri- tance. In H. Trost, editor, Proceedings of KON- VENS '9.~, pages 102 -111, Vienna. Springer.", | |
| "links": null | |
| }, | |
| "BIBREF9": { | |
| "ref_id": "b9", | |
| "title": "P-PATth A compiler for unification-based grammars", | |
| "authors": [ | |
| { | |
| "first": "Susan", | |
| "middle": [ | |
| "Beth" | |
| ], | |
| "last": "Hirsh", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1986, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Susan Beth Hirsh. 1986. P-PATth A compiler for unification-based grammars. Master's the- sis, Stanford University, Stanford, CA.", | |
| "links": null | |
| }, | |
| "BIBREF10": { | |
| "ref_id": "b10", | |
| "title": "Draft ISO Standard for the Prolog language, ISO/IEC JTC1 SC22 WG17 Nl10", | |
| "authors": [], | |
| "year": null, | |
| "venue": "", | |
| "volume": "1", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Draft ISO Standard for the Prolog language, ISO/IEC JTC1 SC22 WG17 Nl10 \"Prolog: Part 1, General core\".", | |
| "links": null | |
| }, | |
| "BIBREF11": { | |
| "ref_id": "b11", | |
| "title": "7-79\u00a3--a type description language for constraint-based grammars", | |
| "authors": [ | |
| { | |
| "first": "Ulrich", | |
| "middle": [], | |
| "last": "Hans", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "Ulrich", | |
| "middle": [], | |
| "last": "Krieger", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "", | |
| "middle": [], | |
| "last": "Schlfer", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1994, | |
| "venue": "Proceedings of the 15th International Conference on Computational Linguistics, COLING-94", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Hans-Ulrich Krieger and Ulrich Schlfer. 1994. 7-79\u00a3--a type description language for constraint-based grammars. In Proceedings of the 15th International Conference on Computa- tional Linguistics, COLING-94, Kyoto, Japan.", | |
| "links": null | |
| }, | |
| "BIBREF12": { | |
| "ref_id": "b12", | |
| "title": "An attributive logic of set descriptions and set operations", | |
| "authors": [ | |
| { | |
| "first": "Suresh", | |
| "middle": [], | |
| "last": "Manandhar", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1994, | |
| "venue": "32nd Annual Meeting of the Association for Computational Linguistics (A CL)", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "255--262", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Suresh Manandhar. 1994. An attributive logic of set descriptions and set operations. In 32nd Annual Meeting of the Association for Compu- tational Linguistics (A CL), pages 255 -262, Las Cruces, NM.", | |
| "links": null | |
| }, | |
| "BIBREF13": { | |
| "ref_id": "b13", | |
| "title": "Deterministic consistency checking of LP constraints", | |
| "authors": [ | |
| { | |
| "first": "Suresh", | |
| "middle": [], | |
| "last": "Manandhar", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1995, | |
| "venue": "Seventh Conference of the European Chapter of the Association for Computational Linguistics (EA CL)", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Suresh Manandhar. 1995. Deterministic con- sistency checking of LP constraints. In Sev- enth Conference of the European Chapter of the Association for Computational Linguistics (EA CL), Dublin.", | |
| "links": null | |
| }, | |
| "BIBREF14": { | |
| "ref_id": "b14", | |
| "title": "Conditional constraints in a CLP-based HPSG implementation", | |
| "authors": [ | |
| { | |
| "first": "Johannes", | |
| "middle": [], | |
| "last": "Matiasek", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1994, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Johannes Matiasek. 1994. Conditional con- straints in a CLP-based HPSG implementation.", | |
| "links": null | |
| }, | |
| "BIBREF15": { | |
| "ref_id": "b15", | |
| "title": "hnplementing systemic classification by unification", | |
| "authors": [ | |
| { | |
| "first": "Christopher", | |
| "middle": [ | |
| "S" | |
| ], | |
| "last": "Mellish", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1988, | |
| "venue": "Computational Linguistics", | |
| "volume": "14", | |
| "issue": "1", | |
| "pages": "40--51", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Christopher S. Mellish. 1988. hnplementing sys- temic classification by unification. Computa- tional Linguistics, 14(1):40-51.", | |
| "links": null | |
| }, | |
| "BIBREF16": { | |
| "ref_id": "b16", | |
| "title": "Term-encodable description spaces", | |
| "authors": [ | |
| { | |
| "first": "S", | |
| "middle": [], | |
| "last": "Christopher", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "", | |
| "middle": [], | |
| "last": "Mellish", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1992, | |
| "venue": "Logic Programming: New Frontiers", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "189--207", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Christopher S. Mellish. 1992. Term-encodable de- scription spaces. In D. R. Brough, editor, Logic Programming: New Frontiers, pages 189 -207. Intellect, Oxford.", | |
| "links": null | |
| }, | |
| "BIBREF17": { | |
| "ref_id": "b17", | |
| "title": "A Uniform Computational Model for Natural Language Parsing and Generation", | |
| "authors": [ | |
| { | |
| "first": "Giinter", | |
| "middle": [], | |
| "last": "Neumann", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "Gertjan", | |
| "middle": [], | |
| "last": "Van Noord ; Nantes", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "F", | |
| "middle": [ | |
| "Giinter" | |
| ], | |
| "last": "Neumann", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1992, | |
| "venue": "Proceedings of the 14th International Conference on Computational Linguistics", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Giinter Neumann and Gertjan van Noord. 1992. Self-monitoring with reversible grammars. In Proceedings of the 14th International Confer- ence on Computational Linguistics, Nantes, F. Giinter Neumann. 1994. A Uniform Computa- tional Model for Natural Language Parsing and Generation. Ph.D. thesis, Universitit des Saar- landes, Saabriicken.", | |
| "links": null | |
| }, | |
| "BIBREF18": { | |
| "ref_id": "b18", | |
| "title": "Fast Natural-Language Parsing Using Explanation-Based Learning", | |
| "authors": [ | |
| { | |
| "first": "Christer", | |
| "middle": [], | |
| "last": "Samuelsson", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1994, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Christer Samuelsson. 1994. Fast Natural- Language Parsing Using Explanation-Based Learning. Ph.D. thesis, The Royal Institute of Technology and Stockholm University, Stock- holm.", | |
| "links": null | |
| }, | |
| "BIBREF19": { | |
| "ref_id": "b19", | |
| "title": "Compiling feature structures into terms: A case study in Prolog", | |
| "authors": [ | |
| { | |
| "first": "Andreas", | |
| "middle": [ | |
| "P" | |
| ], | |
| "last": "Schster", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1993, | |
| "venue": "", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Andreas P. SchSter. 1993. Compiling feature structures into terms: A case study in Prolog. Technical Report RP-55, University of Edin- burgh, Centre for Cognitive Science.", | |
| "links": null | |
| }, | |
| "BIBREF20": { | |
| "ref_id": "b20", | |
| "title": "Object-oriented concurrent constraint programming in Oz", | |
| "authors": [ | |
| { | |
| "first": "Gert", | |
| "middle": [], | |
| "last": "Smolka", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "Martin", | |
| "middle": [], | |
| "last": "Henz", | |
| "suffix": "" | |
| }, | |
| { | |
| "first": "J6rg", | |
| "middle": [], | |
| "last": "Wiirtz", | |
| "suffix": "" | |
| } | |
| ], | |
| "year": 1995, | |
| "venue": "Principles and Practice of Constraint Programming", | |
| "volume": "", | |
| "issue": "", | |
| "pages": "27--48", | |
| "other_ids": {}, | |
| "num": null, | |
| "urls": [], | |
| "raw_text": "Gert Smolka, Martin Henz, and J6rg Wiirtz. 1995. Object-oriented concurrent constraint programming in Oz. In P. van Hentenryck and V. Saraswat, editors, Principles and Practice of Constraint Programming, chapter 2, pages 27- 48. The MIT Press.", | |
| "links": null | |
| } | |
| }, | |
| "ref_entries": { | |
| "FIGREF1": { | |
| "text": "semantics (synsem ! local !cont ! Sem) : = Sem.", | |
| "type_str": "figure", | |
| "uris": null, | |
| "num": null | |
| }, | |
| "TABREF0": { | |
| "type_str": "table", | |
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| "content": "<table><tr><td>2</td><td>The ProFIT</td><td>Language</td></tr><tr><td colspan=\"3\">The set of ProFIT programs is a superset of Pro-</td></tr><tr><td colspan=\"3\">log programs. While a Prolog program consists</td></tr><tr><td colspan=\"3\">only of definite clauses (Prolog is an untyped lan-</td></tr><tr><td colspan=\"3\">guage), a ProFIT program consists of datatype</td></tr><tr><td colspan=\"3\">declarations and definite clauses. The clauses of a</td></tr><tr><td colspan=\"3\">ProFIT program can make use of the datatypes</td></tr><tr><td colspan=\"3\">(sorts, features, templates and finite domains)</td></tr><tr><td colspan=\"3\">that are introduced in the declarations. A ProFIT</td></tr><tr><td colspan=\"2\">program consists of:</td><td/></tr><tr><td/><td colspan=\"2\">\u2022 Declarations for sorts</td></tr><tr><td/><td colspan=\"2\">\u2022 Declarations for features</td></tr><tr><td/><td colspan=\"2\">\u2022 Declarations for templates</td></tr><tr><td/><td colspan=\"2\">\u2022 Declarations for finite domains</td></tr><tr><td/><td>\u2022 Definite clauses</td><td/></tr><tr><td colspan=\"3\">2.1 Sort Declarations</td></tr><tr><td colspan=\"3\">In addition to unsorted Prolog terms, ProFIT al-</td></tr><tr><td colspan=\"3\">lows sorted feature terms, for which the sorts and</td></tr><tr><td colspan=\"3\">features must be declared in advance.</td></tr><tr><td/><td colspan=\"2\">The most general sort is top, and all other sorts</td></tr><tr><td colspan=\"3\">must be subsorts of top. Subsort declarations</td></tr><tr><td colspan=\"3\">have the syntax given in (1)</td></tr></table>", | |
| "num": null | |
| } | |
| } | |
| } | |
| } |