Add packrat-parse, etc

db4
Chris Double 2008-03-28 00:04:08 +13:00
parent f6b7f8197e
commit fa8b311b27
3 changed files with 36 additions and 8 deletions

View File

@ -266,7 +266,7 @@ M: ebnf-non-terminal (transform) ( ast -- parser )
] [ ] make delay sp ;
: transform-ebnf ( string -- object )
'ebnf' [ parse ] packrat-parse parse-result-ast transform ;
'ebnf' packrat-parse parse-result-ast transform ;
: check-parse-result ( result -- result )
dup [
@ -281,7 +281,7 @@ M: ebnf-non-terminal (transform) ( ast -- parser )
] if ;
: ebnf>quot ( string -- hashtable quot )
'ebnf' [ parse ] with-packrat check-parse-result
'ebnf' packrat-parse check-parse-result
parse-result-ast transform dup main swap at compile 1quotation ;
: [EBNF "EBNF]" parse-multiline-string ebnf>quot nip parsed ; parsing

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@ -12,7 +12,7 @@ HELP: parse
{ $description
"Given the input string, parse it using the given parser. The result is a <parse-result> object if "
"the parse was successful, otherwise it is f." }
{ $see-also compile with-packrat } ;
{ $see-also compile with-packrat packrat-parse } ;
HELP: with-packrat
{ $values
@ -23,8 +23,30 @@ HELP: with-packrat
"Calls the quotation with a packrat cache in scope. Usually the quotation will "
"call " { $link parse } " or call a word produced by " { $link compile } "."
"The cache is used to avoid the possible exponential time performace that pegs "
"can have, instead giving linear time at the cost of increased memory usage." }
{ $see-also compile parse } ;
"can have, instead giving linear time at the cost of increased memory usage. "
"Use of this packrat option also allows direct and indirect recursion to "
"be handled in the parser without entering an infinite loop." }
{ $see-also compile parse packrat-parse packrat-call } ;
HELP: packrat-parse
{ $values
{ "input" "a string" }
{ "parser" "a parser" }
{ "result" "a parse-result or f" }
}
{ $description
"Compiles and calls the parser with a packrat cache in scope." }
{ $see-also compile parse packrat-call with-packrat } ;
HELP: packrat-call
{ $values
{ "input" "a string" }
{ "quot" "a quotation with stack effect ( input -- result )" }
{ "result" "a parse-result or f" }
}
{ $description
"Calls the compiled parser with a packrat cache in scope." }
{ $see-also compile packrat-call packrat-parse with-packrat } ;
HELP: compile
{ $values
@ -36,7 +58,7 @@ HELP: compile
"The mapping from parser to compiled word is kept in a cache. If you later change "
"the definition of a parser you'll need to clear this cache with "
{ $link reset-compiled-parsers } " before using " { $link compile } " on that parser again." }
{ $see-also compile with-packrat reset-compiled-parsers } ;
{ $see-also compile with-packrat reset-compiled-parsers packrat-call packrat-parse } ;
HELP: reset-compiled-parsers
{ $description

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@ -67,11 +67,17 @@ GENERIC: (compile) ( parser -- quot )
[ compiled-parser ] with-compilation-unit ;
: parse ( state parser -- result )
compile execute ;
compile execute ; inline
: with-packrat ( quot -- result )
#! Run the quotation with a packrat cache active.
[ H{ } clone packrat ] dip with-variable ;
[ H{ } clone packrat ] dip with-variable ; inline
: packrat-parse ( state parser -- result )
[ parse ] with-packrat ;
: packrat-call ( state quot -- result )
with-packrat ; inline
<PRIVATE