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| author | aarne <aarne@cs.chalmers.se> | 2008-06-25 16:43:48 +0000 |
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| committer | aarne <aarne@cs.chalmers.se> | 2008-06-25 16:43:48 +0000 |
| commit | b96b36f43de3e2f8b58d5f539daa6f6d47f25870 (patch) | |
| tree | 0992334be13cec6538a1dea22fbbf26ad6bdf224 /src/GF/GFCC/doc/gfcc.html | |
| parent | fe367412e0aeb4ad5c02de68e6eca382e0f96984 (diff) | |
removed src for 2.9
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| -rw-r--r-- | src/GF/GFCC/doc/gfcc.html | 809 |
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diff --git a/src/GF/GFCC/doc/gfcc.html b/src/GF/GFCC/doc/gfcc.html deleted file mode 100644 index 8f8c478c0..000000000 --- a/src/GF/GFCC/doc/gfcc.html +++ /dev/null @@ -1,809 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> -<HTML> -<HEAD> -<META NAME="generator" CONTENT="http://txt2tags.sf.net"> -<TITLE>The GFCC Grammar Format</TITLE> -</HEAD><BODY BGCOLOR="white" TEXT="black"> -<P ALIGN="center"><CENTER><H1>The GFCC Grammar Format</H1> -<FONT SIZE="4"> -<I>Aarne Ranta</I><BR> -October 5, 2007 -</FONT></CENTER> - -<P> -Author's address: -<A HREF="http://www.cs.chalmers.se/~aarne"><CODE>http://www.cs.chalmers.se/~aarne</CODE></A> -</P> -<P> -History: -</P> -<UL> -<LI>5 Oct 2007: new, better structured GFCC with full expressive power -<LI>19 Oct: translation of lincats, new figures on C++ -<LI>3 Oct 2006: first version -</UL> - -<H2>What is GFCC</H2> -<P> -GFCC is a low-level format for GF grammars. Its aim is to contain the minimum -that is needed to process GF grammars at runtime. This minimality has three -advantages: -</P> -<UL> -<LI>compact grammar files and run-time objects -<LI>time and space efficient processing -<LI>simple definition of interpreters -</UL> - -<P> -Thus we also want to call GFCC the <B>portable grammar format</B>. -</P> -<P> -The idea is that all embedded GF applications use GFCC. -The GF system would be primarily used as a compiler and as a grammar -development tool. -</P> -<P> -Since GFCC is implemented in BNFC, a parser of the format is readily -available for C, C++, C#, Haskell, Java, and OCaml. Also an XML -representation can be generated in BNFC. A -<A HREF="../">reference implementation</A> -of linearization and some other functions has been written in Haskell. -</P> -<H2>GFCC vs. GFC</H2> -<P> -GFCC is aimed to replace GFC as the run-time grammar format. GFC was designed -to be a run-time format, but also to -support separate compilation of grammars, i.e. -to store the results of compiling -individual GF modules. But this means that GFC has to contain extra information, -such as type annotations, which is only needed in compilation and not at -run-time. In particular, the pattern matching syntax and semantics of GFC is -complex and therefore difficult to implement in new platforms. -</P> -<P> -Actually, GFC is planned to be omitted also as the target format of -separate compilation, where plain GF (type annotated and partially evaluated) -will be used instead. GFC provides only marginal advantages as a target format -compared with GF, and it is therefore just extra weight to carry around this -format. -</P> -<P> -The main differences of GFCC compared with GFC (and GF) can be summarized as follows: -</P> -<UL> -<LI>there are no modules, and therefore no qualified names -<LI>a GFCC grammar is multilingual, and consists of a common abstract syntax - together with one concrete syntax per language -<LI>records and tables are replaced by arrays -<LI>record labels and parameter values are replaced by integers -<LI>record projection and table selection are replaced by array indexing -<LI>even though the format does support dependent types and higher-order abstract - syntax, there is no interpreted yet that does this -</UL> - -<P> -Here is an example of a GF grammar, consisting of three modules, -as translated to GFCC. The representations are aligned; thus they do not completely -reflect the order of judgements in GFCC files, which have different orders of -blocks of judgements, and alphabetical sorting. -</P> -<PRE> - grammar Ex(Eng,Swe); - - abstract Ex = { abstract { - cat cat - S ; NP ; VP ; NP[]; S[]; VP[]; - fun fun - Pred : NP -> VP -> S ; Pred=[(($ 0! 1),(($ 1! 0)!($ 0! 0)))]; - She, They : NP ; She=[0,"she"]; - Sleep : VP ; They=[1,"they"]; - Sleep=[["sleeps","sleep"]]; - } } ; - - concrete Eng of Ex = { concrete Eng { - lincat lincat - S = {s : Str} ; S=[()]; - NP = {s : Str ; n : Num} ; NP=[1,()]; - VP = {s : Num => Str} ; VP=[[(),()]]; - param - Num = Sg | Pl ; - lin lin - Pred np vp = { Pred=[(($ 0! 1),(($ 1! 0)!($ 0! 0)))]; - s = np.s ++ vp.s ! np.n} ; - She = {s = "she" ; n = Sg} ; She=[0,"she"]; - They = {s = "they" ; n = Pl} ; They = [1, "they"]; - Sleep = {s = table { Sleep=[["sleeps","sleep"]]; - Sg => "sleeps" ; - Pl => "sleep" - } - } ; - } } ; - - concrete Swe of Ex = { concrete Swe { - lincat lincat - S = {s : Str} ; S=[()]; - NP = {s : Str} ; NP=[()]; - VP = {s : Str} ; VP=[()]; - param - Num = Sg | Pl ; - lin lin - Pred np vp = { Pred = [(($0!0),($1!0))]; - s = np.s ++ vp.s} ; - She = {s = "hon"} ; She = ["hon"]; - They = {s = "de"} ; They = ["de"]; - Sleep = {s = "sover"} ; Sleep = ["sover"]; - } } ; -</PRE> -<P></P> -<H2>The syntax of GFCC files</H2> -<P> -The complete BNFC grammar, from which -the rules in this section are taken, is in the file -<A HREF="../DataGFCC.cf"><CODE>GF/GFCC/GFCC.cf</CODE></A>. -</P> -<H3>Top level</H3> -<P> -A grammar has a header telling the name of the abstract syntax -(often specifying an application domain), and the names of -the concrete languages. The abstract syntax and the concrete -syntaxes themselves follow. -</P> -<PRE> - Grm. Grammar ::= - "grammar" CId "(" [CId] ")" ";" - Abstract ";" - [Concrete] ; - - Abs. Abstract ::= - "abstract" "{" - "flags" [Flag] - "fun" [FunDef] - "cat" [CatDef] - "}" ; - - Cnc. Concrete ::= - "concrete" CId "{" - "flags" [Flag] - "lin" [LinDef] - "oper" [LinDef] - "lincat" [LinDef] - "lindef" [LinDef] - "printname" [LinDef] - "}" ; -</PRE> -<P> -This syntax organizes each module to a sequence of <B>fields</B>, such -as flags, linearizations, operations, linearization types, etc. -It is envisaged that particular applications can ignore some -of the fields, typically so that earlier fields are more -important than later ones. -</P> -<P> -The judgement forms have the following syntax. -</P> -<PRE> - Flg. Flag ::= CId "=" String ; - Cat. CatDef ::= CId "[" [Hypo] "]" ; - Fun. FunDef ::= CId ":" Type "=" Exp ; - Lin. LinDef ::= CId "=" Term ; -</PRE> -<P> -For the run-time system, the reference implementation in Haskell -uses a structure that gives efficient look-up: -</P> -<PRE> - data GFCC = GFCC { - absname :: CId , - cncnames :: [CId] , - abstract :: Abstr , - concretes :: Map CId Concr - } - - data Abstr = Abstr { - aflags :: Map CId String, -- value of a flag - funs :: Map CId (Type,Exp), -- type and def of a fun - cats :: Map CId [Hypo], -- context of a cat - catfuns :: Map CId [CId] -- funs yielding a cat (redundant, for fast lookup) - } - - data Concr = Concr { - flags :: Map CId String, -- value of a flag - lins :: Map CId Term, -- lin of a fun - opers :: Map CId Term, -- oper generated by subex elim - lincats :: Map CId Term, -- lin type of a cat - lindefs :: Map CId Term, -- lin default of a cat - printnames :: Map CId Term -- printname of a cat or a fun - } -</PRE> -<P> -These definitions are from <A HREF="../DataGFCC.hs"><CODE>GF/GFCC/DataGFCC.hs</CODE></A>. -</P> -<P> -Identifiers (<CODE>CId</CODE>) are like <CODE>Ident</CODE> in GF, except that -the compiler produces constants prefixed with <CODE>_</CODE> in -the common subterm elimination optimization. -</P> -<PRE> - token CId (('_' | letter) (letter | digit | '\'' | '_')*) ; -</PRE> -<P></P> -<H3>Abstract syntax</H3> -<P> -Types are first-order function types built from argument type -contexts and value types. -category symbols. Syntax trees (<CODE>Exp</CODE>) are -rose trees with nodes consisting of a head (<CODE>Atom</CODE>) and -bound variables (<CODE>CId</CODE>). -</P> -<PRE> - DTyp. Type ::= "[" [Hypo] "]" CId [Exp] ; - DTr. Exp ::= "[" "(" [CId] ")" Atom [Exp] "]" ; - Hyp. Hypo ::= CId ":" Type ; -</PRE> -<P> -The head Atom is either a function -constant, a bound variable, or a metavariable, or a string, integer, or float -literal. -</P> -<PRE> - AC. Atom ::= CId ; - AS. Atom ::= String ; - AI. Atom ::= Integer ; - AF. Atom ::= Double ; - AM. Atom ::= "?" Integer ; -</PRE> -<P> -The context-free types and trees of the "old GFCC" are special -cases, which can be defined as follows: -</P> -<PRE> - Typ. Type ::= [CId] "->" CId - Typ args val = DTyp [Hyp (CId "_") arg | arg <- args] val - - Tr. Exp ::= "(" CId [Exp] ")" - Tr fun exps = DTr [] fun exps -</PRE> -<P> -To store semantic (<CODE>def</CODE>) definitions by cases, the following expression -form is provided, but it is only meaningful in the last field of a function -declaration in an abstract syntax: -</P> -<PRE> - EEq. Exp ::= "{" [Equation] "}" ; - Equ. Equation ::= [Exp] "->" Exp ; -</PRE> -<P> -Notice that expressions are used to encode patterns. Primitive notions -(the default semantics in GF) are encoded as empty sets of equations -(<CODE>[]</CODE>). For a constructor (canonical form) of a category <CODE>C</CODE>, we -aim to use the encoding as the application <CODE>(_constr C)</CODE>. -</P> -<H3>Concrete syntax</H3> -<P> -Linearization terms (<CODE>Term</CODE>) are built as follows. -Constructor names are shown to make the later code -examples readable. -</P> -<PRE> - R. Term ::= "[" [Term] "]" ; -- array (record/table) - P. Term ::= "(" Term "!" Term ")" ; -- access to field (projection/selection) - S. Term ::= "(" [Term] ")" ; -- concatenated sequence - K. Term ::= Tokn ; -- token - V. Term ::= "$" Integer ; -- argument (subtree) - C. Term ::= Integer ; -- array index (label/parameter value) - FV. Term ::= "[|" [Term] "|]" ; -- free variation - TM. Term ::= "?" ; -- linearization of metavariable -</PRE> -<P> -Tokens are strings or (maybe obsolescent) prefix-dependent -variant lists. -</P> -<PRE> - KS. Tokn ::= String ; - KP. Tokn ::= "[" "pre" [String] "[" [Variant] "]" "]" ; - Var. Variant ::= [String] "/" [String] ; -</PRE> -<P> -Two special forms of terms are introduced by the compiler -as optimizations. They can in principle be eliminated, but -their presence makes grammars much more compact. Their semantics -will be explained in a later section. -</P> -<PRE> - F. Term ::= CId ; -- global constant - W. Term ::= "(" String "+" Term ")" ; -- prefix + suffix table -</PRE> -<P> -There is also a deprecated form of "record parameter alias", -</P> -<PRE> - RP. Term ::= "(" Term "@" Term ")"; -- DEPRECATED -</PRE> -<P> -which will be removed when the migration to new GFCC is complete. -</P> -<H2>The semantics of concrete syntax terms</H2> -<P> -The code in this section is from <A HREF="../Linearize.hs"><CODE>GF/GFCC/Linearize.hs</CODE></A>. -</P> -<H3>Linearization and realization</H3> -<P> -The linearization algorithm is essentially the same as in -GFC: a tree is linearized by evaluating its linearization term -in the environment of the linearizations of the subtrees. -Literal atoms are linearized in the obvious way. -The function also needs to know the language (i.e. concrete syntax) -in which linearization is performed. -</P> -<PRE> - linExp :: GFCC -> CId -> Exp -> Term - linExp gfcc lang tree@(DTr _ at trees) = case at of - AC fun -> comp (Prelude.map lin trees) $ look fun - AS s -> R [kks (show s)] -- quoted - AI i -> R [kks (show i)] - AF d -> R [kks (show d)] - AM -> TM - where - lin = linExp gfcc lang - comp = compute gfcc lang - look = lookLin gfcc lang -</PRE> -<P> -TODO: bindings must be supported. -</P> -<P> -The result of linearization is usually a record, which is realized as -a string using the following algorithm. -</P> -<PRE> - realize :: Term -> String - realize trm = case trm of - R (t:_) -> realize t - S ss -> unwords $ Prelude.map realize ss - K (KS s) -> s - K (KP s _) -> unwords s ---- prefix choice TODO - W s t -> s ++ realize t - FV (t:_) -> realize t - TM -> "?" -</PRE> -<P> -Notice that realization always picks the first field of a record. -If a linearization type has more than one field, the first field -does not necessarily contain the desired string. -Also notice that the order of record fields in GFCC is not necessarily -the same as in GF source. -</P> -<H3>Term evaluation</H3> -<P> -Evaluation follows call-by-value order, with two environments -needed: -</P> -<UL> -<LI>the grammar (a concrete syntax) to give the global constants -<LI>an array of terms to give the subtree linearizations -</UL> - -<P> -The code is presented in one-level pattern matching, to -enable reimplementations in languages that do not permit -deep patterns (such as Java and C++). -</P> -<PRE> - compute :: GFCC -> CId -> [Term] -> Term -> Term - compute gfcc lang args = comp where - comp trm = case trm of - P r p -> proj (comp r) (comp p) - W s t -> W s (comp t) - R ts -> R $ Prelude.map comp ts - V i -> idx args (fromInteger i) -- already computed - F c -> comp $ look c -- not computed (if contains V) - FV ts -> FV $ Prelude.map comp ts - S ts -> S $ Prelude.filter (/= S []) $ Prelude.map comp ts - _ -> trm - - look = lookOper gfcc lang - - idx xs i = xs !! i - - proj r p = case (r,p) of - (_, FV ts) -> FV $ Prelude.map (proj r) ts - (W s t, _) -> kks (s ++ getString (proj t p)) - _ -> comp $ getField r (getIndex p) - - getString t = case t of - K (KS s) -> s - _ -> trace ("ERROR in grammar compiler: string from "++ show t) "ERR" - - getIndex t = case t of - C i -> fromInteger i - RP p _ -> getIndex p - TM -> 0 -- default value for parameter - _ -> trace ("ERROR in grammar compiler: index from " ++ show t) 0 - - getField t i = case t of - R rs -> idx rs i - RP _ r -> getField r i - TM -> TM - _ -> trace ("ERROR in grammar compiler: field from " ++ show t) t -</PRE> -<P></P> -<H3>The special term constructors</H3> -<P> -The three forms introduced by the compiler may a need special -explanation. -</P> -<P> -Global constants -</P> -<PRE> - Term ::= CId ; -</PRE> -<P> -are shorthands for complex terms. They are produced by the -compiler by (iterated) <B>common subexpression elimination</B>. -They are often more powerful than hand-devised code sharing in the source -code. They could be computed off-line by replacing each identifier by -its definition. -</P> -<P> -<B>Prefix-suffix tables</B> -</P> -<PRE> - Term ::= "(" String "+" Term ")" ; -</PRE> -<P> -represent tables of word forms divided to the longest common prefix -and its array of suffixes. In the example grammar above, we have -</P> -<PRE> - Sleep = [("sleep" + ["s",""])] -</PRE> -<P> -which in fact is equal to the array of full forms -</P> -<PRE> - ["sleeps", "sleep"] -</PRE> -<P> -The power of this construction comes from the fact that suffix sets -tend to be repeated in a language, and can therefore be collected -by common subexpression elimination. It is this technique that -explains the used syntax rather than the more accurate -</P> -<PRE> - "(" String "+" [String] ")" -</PRE> -<P> -since we want the suffix part to be a <CODE>Term</CODE> for the optimization to -take effect. -</P> -<H2>Compiling to GFCC</H2> -<P> -Compilation to GFCC is performed by the GF grammar compiler, and -GFCC interpreters need not know what it does. For grammar writers, -however, it might be interesting to know what happens to the grammars -in the process. -</P> -<P> -The compilation phases are the following -</P> -<OL> -<LI>type check and partially evaluate GF source -<LI>create a symbol table mapping the GF parameter and record types to - fixed-size arrays, and parameter values and record labels to integers -<LI>traverse the linearization rules replacing parameters and labels by integers -<LI>reorganize the created GF grammar so that it has just one abstract syntax - and one concrete syntax per language -<LI>TODO: apply UTF8 encoding to the grammar, if not yet applied (this is told by the - <CODE>coding</CODE> flag) -<LI>translate the GF grammar object to a GFCC grammar object, using a simple - compositional mapping -<LI>perform the word-suffix optimization on GFCC linearization terms -<LI>perform subexpression elimination on each concrete syntax module -<LI>print out the GFCC code -</OL> - -<H3>Problems in GFCC compilation</H3> -<P> -Two major problems had to be solved in compiling GF to GFCC: -</P> -<UL> -<LI>consistent order of tables and records, to permit the array translation -<LI>run-time variables in complex parameter values. -</UL> - -<P> -The current implementation is still experimental and may fail -to generate correct code. Any errors remaining are likely to be -related to the two problems just mentioned. -</P> -<P> -The order problem is solved in slightly different ways for tables and records. -In both cases, <B>eta expansion</B> is used to establish a -canonical order. Tables are ordered by applying the preorder induced -by <CODE>param</CODE> definitions. Records are ordered by sorting them by labels. -This means that -e.g. the <CODE>s</CODE> field will in general no longer appear as the first -field, even if it does so in the GF source code. But relying on the -order of fields in a labelled record would be misplaced anyway. -</P> -<P> -The canonical form of records is further complicated by lock fields, -i.e. dummy fields of form <CODE>lock_C = <></CODE>, which are added to grammar -libraries to force intensionality of linearization types. The problem -is that the absence of a lock field only generates a warning, not -an error. Therefore a GF grammar can contain objects of the same -type with and without a lock field. This problem was solved in GFCC -generation by just removing all lock fields (defined as fields whose -type is the empty record type). This has the further advantage of -(slightly) reducing the grammar size. More importantly, it is safe -to remove lock fields, because they are never used in computation, -and because intensional types are only needed in grammars reused -as libraries, not in grammars used at runtime. -</P> -<P> -While the order problem is rather bureaucratic in nature, run-time -variables are an interesting problem. They arise in the presence -of complex parameter values, created by argument-taking constructors -and parameter records. To give an example, consider the GF parameter -type system -</P> -<PRE> - Number = Sg | Pl ; - Person = P1 | P2 | P3 ; - Agr = Ag Number Person ; -</PRE> -<P> -The values can be translated to integers in the expected way, -</P> -<PRE> - Sg = 0, Pl = 1 - P1 = 0, P2 = 1, P3 = 2 - Ag Sg P1 = 0, Ag Sg P2 = 1, Ag Sg P3 = 2, - Ag Pl P1 = 3, Ag Pl P2 = 4, Ag Pl P3 = 5 -</PRE> -<P> -However, an argument of <CODE>Agr</CODE> can be a run-time variable, as in -</P> -<PRE> - Ag np.n P3 -</PRE> -<P> -This expression must first be translated to a case expression, -</P> -<PRE> - case np.n of { - 0 => 2 ; - 1 => 5 - } -</PRE> -<P> -which can then be translated to the GFCC term -</P> -<PRE> - ([2,5] ! ($0 ! $1)) -</PRE> -<P> -assuming that the variable <CODE>np</CODE> is the first argument and that its -<CODE>Number</CODE> field is the second in the record. -</P> -<P> -This transformation of course has to be performed recursively, since -there can be several run-time variables in a parameter value: -</P> -<PRE> - Ag np.n np.p -</PRE> -<P> -A similar transformation would be possible to deal with the double -role of parameter records discussed above. Thus the type -</P> -<PRE> - RNP = {n : Number ; p : Person} -</PRE> -<P> -could be uniformly translated into the set <CODE>{0,1,2,3,4,5}</CODE> -as <CODE>Agr</CODE> above. Selections would be simple instances of indexing. -But any projection from the record should be translated into -a case expression, -</P> -<PRE> - rnp.n ===> - case rnp of { - 0 => 0 ; - 1 => 0 ; - 2 => 0 ; - 3 => 1 ; - 4 => 1 ; - 5 => 1 - } -</PRE> -<P> -To avoid the code bloat resulting from this, we have chosen to -deal with records by a <B>currying</B> transformation: -</P> -<PRE> - table {n : Number ; p : Person} {... ...} - ===> - table Number {Sg => table Person {...} ; table Person {...}} -</PRE> -<P> -This is performed when GFCC is generated. Selections with -records have to be treated likewise, -</P> -<PRE> - t ! r ===> t ! r.n ! r.p -</PRE> -<P></P> -<H3>The representation of linearization types</H3> -<P> -Linearization types (<CODE>lincat</CODE>) are not needed when generating with -GFCC, but they have been added to enable parser generation directly from -GFCC. The linearization type definitions are shown as a part of the -concrete syntax, by using terms to represent types. Here is the table -showing how different linearization types are encoded. -</P> -<PRE> - P* = max(P) -- parameter type - {r1 : T1 ; ... ; rn : Tn}* = [T1*,...,Tn*] -- record - (P => T)* = [T* ,...,T*] -- table, size(P) cases - Str* = () -</PRE> -<P> -For example, the linearization type <CODE>present/CatEng.NP</CODE> is -translated as follows: -</P> -<PRE> - NP = { - a : { -- 6 = 2*3 values - n : {ParamX.Number} ; -- 2 values - p : {ParamX.Person} -- 3 values - } ; - s : {ResEng.Case} => Str -- 3 values - } - - __NP = [[1,2],[(),(),()]] -</PRE> -<P></P> -<H3>Running the compiler and the GFCC interpreter</H3> -<P> -GFCC generation is a part of the -<A HREF="http://www.cs.chalmers.se/Cs/Research/Language-technology/darcs/GF/doc/darcs.html">developers' version</A> -of GF since September 2006. To invoke the compiler, the flag -<CODE>-printer=gfcc</CODE> to the command -<CODE>pm = print_multi</CODE> is used. It is wise to recompile the grammar from -source, since previously compiled libraries may not obey the canonical -order of records. -Here is an example, performed in -<A HREF="../../../../../examples/bronzeage">example/bronzeage</A>. -</P> -<PRE> - i -src -path=.:prelude:resource-1.0/* -optimize=all_subs BronzeageEng.gf - i -src -path=.:prelude:resource-1.0/* -optimize=all_subs BronzeageGer.gf - strip - pm -printer=gfcc | wf bronze.gfcc -</PRE> -<P> -There is also an experimental batch compiler, which does not use the GFC -format or the record aliases. It can be produced by -</P> -<PRE> - make gfc -</PRE> -<P> -in <CODE>GF/src</CODE>, and invoked by -</P> -<PRE> - gfc --make FILES -</PRE> -<P></P> -<H2>The reference interpreter</H2> -<P> -The reference interpreter written in Haskell consists of the following files: -</P> -<PRE> - -- source file for BNFC - GFCC.cf -- labelled BNF grammar of gfcc - - -- files generated by BNFC - AbsGFCC.hs -- abstrac syntax datatypes - ErrM.hs -- error monad used internally - LexGFCC.hs -- lexer of gfcc files - ParGFCC.hs -- parser of gfcc files and syntax trees - PrintGFCC.hs -- printer of gfcc files and syntax trees - - -- hand-written files - DataGFCC.hs -- grammar datatype, post-parser grammar creation - Linearize.hs -- linearization and evaluation - Macros.hs -- utilities abstracting away from GFCC datatypes - Generate.hs -- random and exhaustive generation, generate-and-test parsing - API.hs -- functionalities accessible in embedded GF applications - Generate.hs -- random and exhaustive generation - Shell.hs -- main function - a simple command interpreter -</PRE> -<P> -It is included in the -<A HREF="http://www.cs.chalmers.se/Cs/Research/Language-technology/darcs/GF/doc/darcs.html">developers' version</A> -of GF, in the subdirectories <A HREF="../"><CODE>GF/src/GF/GFCC</CODE></A> and -<A HREF="../../Devel"><CODE>GF/src/GF/Devel</CODE></A>. -</P> -<P> -As of September 2007, default parsing in main GF uses GFCC (implemented by Krasimir -Angelov). The interpreter uses the relevant modules -</P> -<PRE> - GF/Conversions/SimpleToFCFG.hs -- generate parser from GFCC - GF/Parsing/FCFG.hs -- run the parser -</PRE> -<P></P> -<P> -To compile the interpreter, type -</P> -<PRE> - make gfcc -</PRE> -<P> -in <CODE>GF/src</CODE>. To run it, type -</P> -<PRE> - ./gfcc <GFCC-file> -</PRE> -<P> -The available commands are -</P> -<UL> -<LI><CODE>gr <Cat> <Int></CODE>: generate a number of random trees in category. - and show their linearizations in all languages -<LI><CODE>grt <Cat> <Int></CODE>: generate a number of random trees in category. - and show the trees and their linearizations in all languages -<LI><CODE>gt <Cat> <Int></CODE>: generate a number of trees in category from smallest, - and show their linearizations in all languages -<LI><CODE>gtt <Cat> <Int></CODE>: generate a number of trees in category from smallest, - and show the trees and their linearizations in all languages -<LI><CODE>p <Lang> <Cat> <String></CODE>: parse a string into a set of trees -<LI><CODE>lin <Tree></CODE>: linearize tree in all languages, also showing full records -<LI><CODE>q</CODE>: terminate the system cleanly -</UL> - -<H2>Embedded formats</H2> -<UL> -<LI>JavaScript: compiler of linearization and abstract syntax -<P></P> -<LI>Haskell: compiler of abstract syntax and interpreter with parsing, - linearization, and generation -<P></P> -<LI>C: compiler of linearization (old GFCC) -<P></P> -<LI>C++: embedded interpreter supporting linearization (old GFCC) -</UL> - -<H2>Some things to do</H2> -<P> -Support for dependent types, higher-order abstract syntax, and -semantic definition in GFCC generation and interpreters. -</P> -<P> -Replacing the entire GF shell by one based on GFCC. -</P> -<P> -Interpreter in Java. -</P> -<P> -Hand-written parsers for GFCC grammars to reduce code size -(and efficiency?) of interpreters. -</P> -<P> -Binary format and/or file compression of GFCC output. -</P> -<P> -Syntax editor based on GFCC. -</P> -<P> -Rewriting of resource libraries in order to exploit the -word-suffix sharing better (depth-one tables, as in FM). -</P> - -<!-- html code generated by txt2tags 2.3 (http://txt2tags.sf.net) --> -<!-- cmdline: txt2tags -thtml gfcc.txt --> -</BODY></HTML> |