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Implement packrat algorithm

db4
Chris Double 2008-03-27 11:23:58 +13:00
parent bd33e2fef9
commit 2614792254
1 changed files with 14 additions and 5 deletions
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19
extra/peg/peg.factor
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@ -3,7 +3,8 @@
USING: kernel sequences strings namespaces math assocs shuffle USING: kernel sequences strings namespaces math assocs shuffle
vectors arrays combinators.lib math.parser match vectors arrays combinators.lib math.parser match
unicode.categories sequences.lib compiler.units parser unicode.categories sequences.lib compiler.units parser
words quotations effects memoize accessors combinators.cleave ; words quotations effects memoize accessors
combinators.cleave locals ;
IN: peg IN: peg
TUPLE: parse-result remaining ast ; TUPLE: parse-result remaining ast ;
@ -14,14 +15,22 @@ SYMBOL: ignore
parse-result construct-boa ; parse-result construct-boa ;
SYMBOL: compiled-parsers SYMBOL: compiled-parsers
SYMBOL: packrat
SYMBOL: failed
GENERIC: (compile) ( parser -- quot ) GENERIC: (compile) ( parser -- quot )
:: run-packrat-parser ( input quot c -- result )
input slice? [ input slice-from ] [ 0 ] if
quot c [ drop H{ } clone ] cache
[
drop input quot call
] cache* ; inline
: run-parser ( input quot -- result ) : run-parser ( input quot -- result )
#! Eventually this will be replaced with something that #! If a packrat cache is available, use memoization for
#! can do packrat parsing by memoizing the results of #! packrat parsing, otherwise do a standard peg call.
#! a parser. For now, it just calls the quotation. packrat get [ run-packrat-parser ] [ call ] if* ; inline
call ; inline
: compiled-parser ( parser -- word ) : compiled-parser ( parser -- word )
#! Look to see if the given parser has been compiled. #! Look to see if the given parser has been compiled.