=GF Command Help=

Each command has a long and a short name, options, and zero or more
arguments. Commands are sorted by functionality. The short name is
given first.

Commands and options marked with * are currently not implemented.

==Commands that change the state==

```
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
        .gfe   example-based grammar files (only with the -ex option)
        .gfwl  multilingual word list (preprocessed to abs + cncs)
        .ebnf  Extended BNF format
        .cf    Context-free (BNF) format
        .trc   TransferCore 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          from source: ignore precompiled gfc and gfr files
      -gfc          from gfc: use compiled modules whenever they exist
      -retain       retain operations: read resource modules (needed in comm cc) 
      -nocf         don't build old-style context-free grammar (default without HOAS)
      -docf         do build old-style context-free grammar (default with HOAS)
      -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)
      -ex           preprocess .gfe files if needed
      -prob         read probabilities from top grammar file  (format --# prob Fun Double)
      -treebank     read a treebank file to memory (xml 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)
      -probs        read probabilities from file (format (--# prob) Fun Double)
      -preproc      use a preprocessor on each source file
      -noparse      read nonparsable functions from file (format --# noparse Funs) 
  examples:
      i English.gf                      -- ordinary import of Concrete
      i -retain german/ParadigmsGer.gf  -- import of Resource to test

r, reload: r
      Executes the previous import (i) command.
      
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.

dc, define_command Name Anything
      Add a new defined command. The Name must star with '%'. Later,
      if 'Name X' is used, it is replaced by Anything where #1 is replaced
      by X. 
      Restrictions: Currently at most one argument is possible, and a defined
      command cannot appear in a pipe.     
      To see what definitions are in scope, use help -defs.
  examples:
      dc %tnp p -cat=NP -lang=Eng #1 | l -lang=Swe    -- translate NPs
      %tnp "this man"                                 -- translate and parse

dt, define_term Name Tree
      Add a constant for a tree. The constant can later be called by
      prefixing it with '$'. 
      Restriction: These terms are not yet usable as a subterm. 
      To see what definitions are in scope, use help -defs.
  examples:
      p -cat=NP "this man" | dt tm    -- define tm as parse result
      l -all $tm                      -- linearize tm in all forms
```

==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
      -startcat  -- The start category of the generated grammar.
                    Only supported by some grammar printers.
  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
  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:  
      -struct  bracketed form
      -table   show parameters (not compatible with -record, -all)
      -record  record, i.e. explicit GF concrete syntax term (not compatible with -table, -all)
      -all     show all forms and variants (not compatible with -record, -table)
      -multi   linearize to all languages (can be combined with the other options)
  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 for batch input:
      -lines     parse each line of input separately, ignoring empty lines
      -all       as -lines, but also parse empty lines
      -prob      rank results by probability
      -cut       stop after first lexing result leading to parser success
      -fail      show strings whose parse fails prefixed by #FAIL
      -ambiguous show strings that have more than one parse prefixed by #AMBIGUOUS
  options for selecting parsing method:
      -fcfg    parse using a fast variant of MCFG (default is no HOAS in grammar)
      -old     parse using an overgenerating CFG (default if HOAS in grammar)
      -cfg     parse using a much less overgenerating CFG
      -mcfg    parse using an even less overgenerating MCFG
      Note:    the first time parsing with -cfg, -mcfg, and -fcfg may take a long time
  options that only work for the -old default parsing method:
      -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
  flags:
      -cat     parse in this category
      -lang    parse in this grammar
      -lexer   filter input through this lexer
      -parser  use this parsing strategy
      -number  return this many results at most
  examples:
      p -cat=S -mcfg "jag är gammal"   -- parse an S with the MCFG
      rf examples.txt | p -lines      -- parse each non-empty line of the file

at, apply_transfer: at (Module.Fun | Fun)
      Transfer a term using Fun from Module, or the topmost transfer
      module. Transfer modules are given in the .trc format. They are
      shown by the 'po' command.
  flags:
     -lang     typecheck the result in this lang instead of default lang
  examples:
     p -lang=Cncdecimal "123" | at num2bin | l   -- convert dec to bin

tb, tree_bank: tb
      Generate a multilingual treebank from a list of trees (default) or compare
      to an existing treebank.
  options:
     -c        compare to existing xml-formatted treebank
     -trees    return the trees of the treebank
     -all      show all linearization alternatives (branches and variants)
     -table    show tables of linearizations with parameters
     -record   show linearization records
     -xml      wrap the treebank (or comparison results) with XML tags
     -mem      write the treebank in memory instead of a file TODO
  examples:
     gr -cat=S -number=100 | tb -xml | wf tb.xml -- random treebank into file
     rf tb.xml | tb -c                           -- compare-test treebank from file
     rf old.xml | tb -trees | tb -xml            -- create new treebank from old

ut, use_treebank: ut String
      Lookup a string in a treebank and return the resulting trees.
      Use 'tb' to create a treebank and 'i -treebank' to read one from
      a file.
   options:
     -assocs   show all string-trees associations in the treebank
     -strings  show all strings in the treebank
     -trees    show all trees in the treebank
     -raw      return the lookup result as string, without typechecking it
   flags:
     -treebank use this treebank (instead of the latest introduced one)
   examples:
     ut "He adds this to that" | l -multi        -- use treebank lookup as parser in translation
     ut -assocs | grep "ComplV2"                 -- show all associations with ComplV2

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

g, grep: g String1 String2
      Grep the String1 in the String2. String2 is read line by line,
      and only those lines that contain String1 are returned.
  flags:
     -v  return those lines that do not contain String1.
  examples:
     pg -printer=cf | grep "mother"  -- show cf rules with word mother

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:
     -table    show output in a similar readable format as 'l -table'
     -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. 
  options:
      -prob    use probabilities (works for nondep types only)
      -cf      use a very fast method (works for nondep types only)
  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
      -all      generate all (can be infinitely many, lazily)
      -lin      linearize result of -all (otherwise, use pipe to linearize)
  flags:
      -depth    generate to this depth (default 3)
      -atoms    take this number of atomic rules of each category (default unlimited)
      -alts     take this number of alternatives at each branch (default unlimited)
      -cat      generate in this category
      -nonub    don't remove duplicates (faster, not effective with -mem)
      -mem      use a memorizing algorithm (often faster, usually more memory-consuming)
      -lang     use the abstract syntax of this grammar
      -number   generate (at most) this number of trees (also works with -all)
      -noexpand don't expand these categories (comma-separated, e.g. -noexpand=V,CN)
      -doexpand only expand these categories (comma-separated, e.g. -doexpand=V,CN)
  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                 -- generate and linearize
      gt -noexpand=NP | l -mark=metacat -- the only NP is meta, linearized "?0 +NP"
      gt | l | p -lines -ambiguous | grep "#AMBIGUOUS" -- show ambiguous strings

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
      -status  show just the work at success, prefixed with "*" at failure
  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

vt, visualize_tree: vt Tree
      Shows the abstract syntax tree via dot and gv (via temporary files
      grphtmp.dot, grphtmp.ps).
  flags:
      -c           show categories only (no functions)
      -f           show functions only (no categories)
      -g           show as graph (sharing uses of the same function)
      -o           just generate the .dot file
  examples:
    p "hello world" | vt -o | wf my.dot ;; ! open -a GraphViz my.dot
    -- This writes the parse tree into my.dot and opens the .dot file
    -- with another application without generating .ps.
```

==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.

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

si, speech_input: si
      Uses an ATK speech recognizer to get speech input. 
  flags:
      -lang: The grammar to use with the speech recognizer.
      -cat: The grammar category to get input in.
      -language: Use acoustic model and dictionary for this language.
      -number: The number of utterances to recognize.

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
       -defs  show user-defined commands and terms
       -FLAG  show the values of FLAG (works for grammar-independent flags)
  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

?, system_command: ? String
      Issues a system command that receives its arguments from GF pipe
      and returns a value to GF.
   example:
      h | ? 'wc -l' | p -cat=Num
```


==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=textvars      like text, 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
    -lexer=ignore        like literals, but ignore unknown words
    -lexer=subseqs       like ignore, but then try all subsequences from longest

-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.
       Each of the flags can have the suffix _subs, which performs
       common subexpression elimination after the main optimization.
       Thus, -optimize=all_subs is the most aggressive one. The _subs
       strategy only works in GFC, and applies therefore in concrete but
       not in 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, parsing strategy. The default is chart. If -cfg or -mcfg are
       selected, only bottomup and topdown are recognized.
    -parser=chart          bottom-up chart parsing
    -parser=bottomup       a more up to date bottom-up strategy
    -parser=topdown        top-down strategy
    -parser=old            an old bottom-up chart parser

-printer, format in which the grammar is printed. The default is
       gfc. Those marked with M are (only) available for pm, the rest
       for pg.
    -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=haskell        abstract syntax in Haskell, with transl to/from GF
    -printer=haskell_gadt   abstract syntax GADT 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
    -printer=stat           show some statistics of generated GFC
    -printer=probs          show probabilities of all functions
    -printer=gsl            Nuance GSL speech recognition grammar
    -printer=jsgf           Java Speech Grammar Format
    -printer=jsgf_sisr_old   Java Speech Grammar Format with semantic tags in 
                                         SISR  WD 20030401 format
    -printer=srgs_abnf       SRGS ABNF format
    -printer=srgs_abnf_non_rec  SRGS ABNF format, without any recursion.
    -printer=srgs_abnf_sisr_old SRGS ABNF format, with semantic tags in
                                         SISR  WD 20030401 format
    -printer=srgs_xml       SRGS XML format
    -printer=srgs_xml_non_rec     SRGS XML format, without any recursion.
    -printer=srgs_xml_prob  SRGS XML format, with weights
    -printer=srgs_xml_sisr_old SRGS XML format, with semantic tags in
                                         SISR  WD 20030401 format
    -printer=vxml           Generate a dialogue system in VoiceXML.
    -printer=slf            a finite automaton in the HTK SLF format
    -printer=slf_graphviz   the same automaton as slf, but in Graphviz format
    -printer=slf_sub        a finite automaton with sub-automata in the 
                            HTK SLF format
    -printer=slf_sub_graphviz the same automaton as slf_sub, but in  
                              Graphviz format
    -printer=fa_graphviz    a finite automaton with labelled edges
    -printer=regular        a regular grammar in a simple BNF
    -printer=unpar          a gfc grammar with parameters eliminated
    -printer=functiongraph  abstract syntax functions in 'dot' format
    -printer=typegraph      abstract syntax categories in 'dot' format
    -printer=transfer       Transfer language datatype (.tr file format)
    -printer=cfg-prolog  M  cfg in prolog format (also pg)
    -printer=gfc-prolog  M  gfc in prolog format (also pg)
    -printer=gfcm        M  gfcm file (default for pm)
    -printer=graph       M  module dependency graph in 'dot' (graphviz) format
    -printer=header      M  gfcm file with header (for GF embedded in Java)
    -printer=js  M  JavaScript type annotator and linearizer
    -printer=mcfg-prolog M  mcfg in prolog format (also pg)
    -printer=missing     M  the missing linearizations of each concrete

-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=nodup        return the term only if it has no constants duplicated
    -transform=nodupatom    return the term only if it has no atomic constants duplicated
    -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 <p>
    -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 "&+"

-mark, marking of parts of tree in linearization. The default is none.
    -mark=metacat        append "+CAT" to every metavariable, showing its category
    -mark=struct         show tree structure with brackets
    -mark=java           show tree structure with XML tags (used in gfeditor)

-coding, Some grammars are in UTF-8, some in isolatin-1.
    If the letters ä (a-umlaut) and ö (o-umlaut) look strange, either
    change your terminal to isolatin-1, or rewrite the grammar with
    'pg -utf8'.
```
