Third version: June 25, 2003, for GF Version 1.2.
Second version: June 17, 2002, for GF Version 1.0.
First version: April 19, 2002.
This document describes the command language available for the user of GF. The GF grammar language is described in other documents.
There is a separate GF Java GUI Manual.
gf Option* File*The files should contain GF grammars, each of which is imported in the environment in which GF starts, in the same way as if GF were first started and the import command i then executed for each of the files. The currently available options are:
Like any program in Unix, GF can be used in a pipeline or a redirection. For instance,
echo "h" | gfstarts GF and executes the help command.
gf <scriptstarts GF and executes the commands in the file script.
The Java GUI is started with the command
jgf File+which executes a simple shell script. The effect is to start GF, import each grammar in the files, and enter the Editor subshell (see below), with which the GUI then communicates.
If a compiled version of GF is not available, GF can be started within the Haskell interpreter GHCI, by the command
make ghciin the GF source directory, followed by ":l GF" in GHCI. Unfortunately, the standard binary of the light-weight Hugs interpreter has insufficient code space for GF.
gf -batch (-s) (-[flag])*It reads standard input, which is typically directed from a script file containing GF commands. Every command read by GF, GF's reply, and the whole run, are enclosed in XML tags:
<!ELEMENT gfbatch ((gfcommand, gfreply)*) > <!ELEMENT gfcommand (#PCDATA) > <!ELEMENT gfreply (#PCDATA) >The optional +s (silence) flag turns off showing commands and the XML structure of the run; it is moreove sent as a global flag to the environment in which the run is performed, together with the other flags appearing in the command line.
Another version of the batch mode is the compiler. Thus
gf -make -s file.gfsilently compiles the file file.gf (as well as all other files that it depends on). All flags to the command i are recognized.
CommandLine ::= Pipeline (";;" Pipeline)* Pipeline ::= Command | Command Arg ("|" Command)* Command ::= CommandId (Option | Flag)* Arg* Arg ::= QuotedString | Tree | File | Lang | IntSeveral commands can be collected on one line, separated by a double semicolon. The effect is that each of the commands is executed; the same effect is achieved in a script by putting the commands on consecutive lines. Thus
i LangEng.gf ;; p -cat=AP "black or green" ;; qis equivalent to
i LangEng.gf p -cat=AP "black or green" qThe one-line variant is handy to use as an argument of the echo command in Unix, to define simple shell scripts using GF.
A pipeline consists of a first command with an argument, producing a result which is sent as argument to the next command. For example,
gr -cat=Phrase | l | sagenerates a random Phrase, linearizes it, and speaks aloud the resulting string. No result is seen in the output, but the phrase is heard spoken.
The trace option -tr can be used to show intermediate results in a pipeline:
rf -tr bible.txt | p -lang=Eng -cat=Text | l -lang=Chireads a string from the file bible.txt (displaying the result), parses it as an English text (without displaying the parse tree), and linearizes the tree into Chinese (displaying the result, as the last command in a pipeline always does).
The Unix Readline facility makes arrow keys, file name completions, etc, available in the GF shell, but only in the GHC-compiled variant. For instance, the up-arrow goes backwards in the command history. If Readline is not available, a command line consisting of an integer n repeats a command n lines back in the history. For instance, 0 repeats the last command, 1 the second-last, etc.
-retainWhat options belong to what commands is explained below.
A flag consists of a hyphen, a flag identifier, an equality sign, and a value identifier, e.g.
-lang=EngWhat flags belong to what commands is explained below. In addition to command lines, flags can be set globally with the sf command (see below), as well as in grammars, using a flags directive, e.g.
flags lexer=code ; startcat=Exp ;either first in a file or immediately after an include directive. In case of conflicts arising from this, the descending order of priority is: command line, grammar, global. The global state is initialized by default values to all available flags.
p "hello world" | l -lang=Swesends a list of terms (the parsing result) to the linearizer, which expects terms, so that the types match. But
p "hello world" | p -lang=Swetries to parse arguments which are already terms, and this is a type error. An error value is also displayed as a string (an error message), but this string is never a meaningful input for a command, so the pipe breaks there.
i, import: i File Reads a grammar from File and compiles it into a GF runtime grammar. Files "include"d in File are read recursively, nubbing repetitions. If a grammar with the same language name is already in the state, it is overwritten - but only if compilation succeeds. The grammar parser depends on the file name suffix: .gf normal GF source .gfc canonical GF .gfr precompiled GF resource .gfcm multilingual canonical GF .ebnf Extended BNF format .cf Context-free (BNF) format options: -old old: parse in GF<2.0 format (not necessary) -v verbose: give lots of messages -s silent: don't give error messages -src source: ignore precompiled gfc and gfr files -retain retain operations: read resource modules (needed in comm cc) -nocf don't build context-free grammar (thus no parser) -nocheckcirc don't eliminate circular rules from CF -cflexer build an optimized parser with separate lexer trie -noemit do not emit code (default with old grammar format) -o do emit code (default with new grammar format) flags: -abs set the name used for abstract syntax (with -old option) -cnc set the name used for concrete syntax (with -old option) -res set the name used for resource (with -old option) -path use the (colon-separated) search path to find modules -optimize select an optimization to override file-defined flags -conversion select parsing method (values strict|nondet) examples: i English.gf -- ordinary import of Concrete i -retain german/ParadigmsGer.gf -- import of Resource to test * rl, remove_language: rl Language Takes away the language from the state. e, empty: e Takes away all languages and resets all global flags. sf, set_flags: sf Flag* The values of the Flags are set for Language. If no language is specified, the flags are set globally. examples: sf -nocpu -- stop showing CPU time sf -lang=Swe -- make Swe the default concrete s, strip: s Prune the state by removing source and resource modules. -- commands that give information about the state pg, print_grammar: pg Prints the actual grammar (overridden by the -lang=X flag). The -printer=X flag sets the format in which the grammar is written. N.B. since grammars are compiled when imported, this command generally does not show the grammar in the same format as the source. In particular, the -printer=latex is not supported. Use the command tg -printer=latex File to print the source grammar in LaTeX. options: -utf8 apply UTF8-encoding to the grammar flags: -printer -lang examples: pg -printer=cf -- show the context-free skeleton pm, print_multigrammar: pm Prints the current multilingual grammar in .gfcm form. (Automatically executes the strip command (s) before doing this.) options: -utf8 apply UTF8 encoding to the tokens in the grammar -utf8id apply UTF8 encoding to the identifiers in the grammar -graph print module dependency graph in 'dot' format examples: pm | wf Letter.gfcm -- print the grammar into the file Letter.gfcm pm -printer=graph | wf D.dot -- then do 'dot -Tps D.dot > D.ps' vg, visualize_graph: vg Show the dependency graph of multilingual grammar via dot and gv. po, print_options: po Print what modules there are in the state. Also prints those flag values in the current state that differ from defaults. pl, print_languages: pl Prints the names of currently available languages. pi, print_info: pi Ident Prints information on the identifier. -- commands that execute and show the session history eh, execute_history: eh File Executes commands in the file. ph, print_history; ph Prints the commands issued during the GF session. The result is readable by the eh command. examples: ph | wf foo.hist" -- save the history into a file -- linearization, parsing, translation, and computation l, linearize: l PattList? Tree Shows all linearization forms of Tree by the actual grammar (which is overridden by the -lang flag). The pattern list has the form [P, ... ,Q] where P,...,Q follow GF syntax for patterns. All those forms are generated that match with the pattern list. Too short lists are filled with variables in the end. Only the -table flag is available if a pattern list is specified. HINT: see GF language specification for the syntax of Pattern and Term. You can also copy and past parsing results. options: -table show parameters -struct bracketed form -record record, i.e. explicit GF concrete syntax term -all show all forms and variants -multi linearize to all languages (the other options don't work) flags: -lang linearize in this grammar -number give this number of forms at most -unlexer filter output through unlexer examples: l -lang=Swe -table -- show full inflection table in Swe p, parse: p String Shows all Trees returned for String by the actual grammar (overridden by the -lang flag), in the category S (overridden by the -cat flag). options: -n non-strict: tolerates morphological errors -ign ignore unknown words when parsing -raw return context-free terms in raw form -v verbose: give more information if parsing fails -new use an experimental method (GF 2.0; sometimes very good) -lines parse each line of input separately, ignoring empty lines -all as -lines, but also parse empty lines flags: -cat parse in this category -lang parse in this grammar -lexer filter input through this lexer -parser use this context-free parsing method -number return this many results at most examples: p -cat=S -new "jag är gammal" -- parse an S with the new method rf examples.txt | p -lines -- parse each non-empty line of the file tt, test_tokenizer: tt String Show the token list sent to the parser when String is parsed. HINT: can be useful when debugging the parser. flags: -lexer use this lexer examples: tt -lexer=codelit "2*(x + 3)" -- a favourite lexer for program code cc, compute_concrete: cc Term Compute a term by concrete syntax definitions. Uses the topmost resource module (the last in listing by command po) to resolve constant names. N.B. You need the flag -retain when importing the grammar, if you want the oper definitions to be retained after compilation; otherwise this command does not expand oper constants. N.B.' The resulting Term is not a term in the sense of abstract syntax, and hence not a valid input to a Tree-demanding command. flags: -res use another module than the topmost one examples: cc -res=ParadigmsFin (nLukko "hyppy") -- inflect "hyppy" with nLukko so, show_operations: so Type Show oper operations with the given value type. Uses the topmost resource module to resolve constant names. N.B. You need the flag -retain when importing the grammar, if you want the oper definitions to be retained after compilation; otherwise this command does not find any oper constants. N.B.' The value type may not be defined in a supermodule of the topmost resource. In that case, use appropriate qualified name. flags: -res use another module than the topmost one examples: so -res=ParadigmsFin ResourceFin.N -- show N-paradigms in ParadigmsFin t, translate: t Lang Lang String Parses String in Lang1 and linearizes the resulting Trees in Lang2. flags: -cat -lexer -parser examples: t Eng Swe -cat=S "every number is even or odd" gr, generate_random: gr Tree? Generates a random Tree of a given category. If a Tree argument is given, the command completes the Tree with values to the metavariables in the tree. flags: -cat generate in this category -lang use the abstract syntax of this grammar -number generate this number of trees (not impl. with Tree argument) -depth use this number of search steps at most examples: gr -cat=Query -- generate in category Query gr (PredVP ? (NegVG ?)) -- generate a random tree of this form gr -cat=S -tr | l -- gererate and linearize gt, generate_trees: gt Tree? Generates all trees up to a given depth. If the depth is large, a small -alts is recommended. If a Tree argument is given, the command completes the Tree with values to the metavariables in the tree. options: -metas also return trees that include metavariables flags: -depth generate to this depth (default 3) -alts take this number of alternatives at each branch (default unlimited) -cat generate in this category -lang use the abstract syntax of this grammar -number generate (at most) this number of trees examples: gt -depth=10 -cat=NP -- generate all NP's to depth 10 gt (PredVP ? (NegVG ?)) -- generate all trees of this form gt -cat=S -tr | l -- gererate and linearize ma, morphologically_analyse: ma String Runs morphological analysis on each word in String and displays the results line by line. options: -short show analyses in bracketed words, instead of separate lines flags: -lang examples: wf Bible.txt | ma -short | wf Bible.tagged -- analyse the Bible -- elementary generation of Strings and Trees ps, put_string: ps String Returns its argument String, like Unix echo. HINT. The strength of ps comes from the possibility to receive the argument from a pipeline, and altering it by the -filter flag. flags: -filter filter the result through this string processor -length cut the string after this number of characters examples: gr -cat=Letter | l | ps -filter=text -- random letter as text pt, put_tree: pt Tree Returns its argument Tree, like a specialized Unix echo. HINT. The strength of pt comes from the possibility to receive the argument from a pipeline, and altering it by the -transform flag. flags: -transform transform the result by this term processor -number generate this number of terms at most examples: p "zero is even" | pt -transform=solve -- solve ?'s in parse result * st, show_tree: st Tree Prints the tree as a string. Unlike pt, this command cannot be used in a pipe to produce a tree, since its output is a string. flags: -printer show the tree in a special format (-printer=xml supported) wt, wrap_tree: wt Fun Wraps the tree as the sole argument of Fun. flags: -c compute the resulting new tree to normal form -- subshells es, editing_session: es Opens an interactive editing session. N.B. Exit from a Fudget session is to the Unix shell, not to GF. options: -f Fudget GUI (necessary for Unicode; only available in X Window System) ts, translation_session: ts Translates input lines from any of the actual languages to all other ones. To exit, type a full stop (.) alone on a line. N.B. Exit from a Fudget session is to the Unix shell, not to GF. HINT: Set -parser and -lexer locally in each grammar. options: -f Fudget GUI (necessary for Unicode; only available in X Windows) -lang prepend translation results with language names flags: -cat the parser category examples: ts -cat=Numeral -lang -- translate numerals, show language names tq, translation_quiz: tq Lang Lang Random-generates translation exercises from Lang1 to Lang2, keeping score of success. To interrupt, type a full stop (.) alone on a line. HINT: Set -parser and -lexer locally in each grammar. flags: -cat examples: tq -cat=NP TestResourceEng TestResourceSwe -- quiz for NPs tl, translation_list: tl Lang Lang Random-generates a list of ten translation exercises from Lang1 to Lang2. The number can be changed by a flag. HINT: use wf to save the exercises in a file. flags: -cat -number examples: tl -cat=NP TestResourceEng TestResourceSwe -- quiz list for NPs mq, morphology_quiz: mq Random-generates morphological exercises, keeping score of success. To interrupt, type a full stop (.) alone on a line. HINT: use printname judgements in your grammar to produce nice expressions for desired forms. flags: -cat -lang examples: mq -cat=N -lang=TestResourceSwe -- quiz for Swedish nouns ml, morphology_list: ml Random-generates a list of ten morphological exercises, keeping score of success. The number can be changed with a flag. HINT: use wf to save the exercises in a file. flags: -cat -lang -number examples: ml -cat=N -lang=TestResourceSwe -- quiz list for Swedish nouns -- IO related commands rf, read_file: rf File Returns the contents of File as a String; error if File does not exist. wf, write_file: wf File String Writes String into File; File is created if it does not exist. N.B. the command overwrites File without a warning. af, append_file: af File Writes String into the end of File; File is created if it does not exist. * tg, transform_grammar: tg File Reads File, parses as a grammar, but instead of compiling further, prints it. The environment is not changed. When parsing the grammar, the same file name suffixes are supported as in the i command. HINT: use this command to print the grammar in another format (the -printer flag); pipe it to wf to save this format. flags: -printer (only -printer=latex supported currently) * cl, convert_latex: cl File Reads File, which is expected to be in LaTeX form. Three environments are treated in special ways: \begGF - \end{verbatim}, which contains GF judgements, \begTGF - \end{verbatim}, which contains a GF expression (displayed) \begInTGF - \end{verbatim}, which contains a GF expressions (inlined). Moreover, certain macros should be included in the file; you can get those macros by applying 'tg -printer=latex foo.gf' to any grammar foo.gf. Notice that the same File can be imported as a GF grammar, consisting of all the judgements in \begGF environments. HINT: pipe with 'wf Foo.tex' to generate a new Latex file. sa, speak_aloud: sa String Uses the Flite speech generator to produce speech for String. Works for American English spelling. examples: h | sa -- listen to the list of commands gr -cat=S | l | sa -- generate a random sentence and speak it aloud h, help: h Command? Displays the paragraph concerning the command from this help file. Without the argument, shows the first lines of all paragraphs. options -all show the whole help file examples: h print_grammar -- show all information on the pg command q, quit: q Exits GF. HINT: you can use 'ph | wf history' to save your session. !, system_command: ! String Issues a system command. No value is returned to GF. example: ! ls -- Flags. The availability of flags is defined separately for each command. -cat, category in which parsing is performed. The default is S. -depth, the search depth in e.g. random generation. The default depends on application. -filter, operation performed on a string. The default is identity. -filter=identity no change -filter=erase erase the text -filter=take100 show the first 100 characters -filter=length show the length of the string -filter=text format as text (punctuation, capitalization) -filter=code format as code (spacing, indentation) -lang, grammar used when executing a grammar-dependent command. The default is the last-imported grammar. -language, voice used by Festival as its --language flag in the sa command. The default is system-dependent. -length, the maximum number of characters shown of a string. The default is unlimited. -lexer, tokenization transforming a string into lexical units for a parser. The default is words. -lexer=words tokens are separated by spaces or newlines -lexer=literals like words, but GF integer and string literals recognized -lexer=vars like words, but "x","x_...","$...$" as vars, "?..." as meta -lexer=chars each character is a token -lexer=code use Haskell's lex -lexer=codevars like code, but treat unknown words as variables, ?? as meta -lexer=text with conventions on punctuation and capital letters -lexer=codelit like code, but treat unknown words as string literals -lexer=textlit like text, but treat unknown words as string literals -lexer=codeC use a C-like lexer -number, the maximum number of generated items in a list. The default is unlimited. -optimize, optimization on generated code. The default is share for concrete, none for resource modules. -optimize=share share common branches in tables -optimize=parametrize first try parametrize then do share with the rest -optimize=values represent tables as courses-of-values -optimize=all first try parametrize then do values with the rest -optimize=none no optimization -parser, Context-free parsing algorithm. Under construction. The default is a chart parser via context-free approximation. -printer, format in which the grammar is printed. The default is gfc. -printer=gfc GFC grammar -printer=gf GF grammar -printer=old old GF grammar -printer=cf context-free grammar, with profiles -printer=bnf context-free grammar, without profiles -printer=lbnf labelled context-free grammar for BNF Converter -printer=plbnf grammar for BNF Converter, with precedence levels *-printer=happy source file for Happy parser generator (use lbnf!) -printer=srg speech recognition grammar -printer=haskell abstract syntax in Haskell, with transl to/from GF -printer=morpho full-form lexicon, long format *-printer=latex LaTeX file (for the tg command) -printer=fullform full-form lexicon, short format *-printer=xml XML: DTD for the pg command, object for st -printer=old old GF: file readable by GF 1.2 -startcat, like -cat, but used in grammars (to avoid clash with keyword cat) -transform, transformation performed on a syntax tree. The default is identity. -transform=identity no change -transform=compute compute by using definitions in the grammar -transform=typecheck return the term only if it is type-correct -transform=solve solve metavariables as derived refinements -transform=context solve metavariables by unique refinements as variables -transform=delete replace the term by metavariable -unlexer, untokenization transforming linearization output into a string. The default is unwords. -unlexer=unwords space-separated token list (like unwords) -unlexer=text format as text: punctuation, capitals, paragraph-unlexer=code format as code (spacing, indentation) -unlexer=textlit like text, but remove string literal quotes -unlexer=codelit like code, but remove string literal quotes -unlexer=concat remove all spaces -unlexer=bind like identity, but bind at "&+" -- *: Commands and options marked with * are not yet implemented.
There are currently three interfaces to the editor: a line-based GF subshell, a Fudget GUI, and a Java GUI. They all use the same abstract command language, the difference being that the subshell has a string syntax for each command, whereas the GUIs mostly use menus and buttons to issue commands. There is a separate GF Java GUI Manual.
The command syntax for the string-based editor is the following:
Start/finish editing: