factor/basis/peg/ebnf/ebnf.factor

572 lines
16 KiB
Factor

! Copyright (C) 2007 Chris Double.
! See http://factorcode.org/license.txt for BSD license.
USING: accessors arrays assocs combinators
combinators.short-circuit effects io.streams.string kernel make
math.parser multiline namespaces parser peg peg.parsers
peg.search quotations sequences splitting stack-checker strings
strings.parser summary unicode.categories words ;
FROM: vocabs.parser => search ;
FROM: peg.search => replace ;
IN: peg.ebnf
: rule ( name word -- parser )
#! Given an EBNF word produced from EBNF: return the EBNF rule
"ebnf-parser" word-prop at ;
ERROR: no-rule rule parser ;
<PRIVATE
: lookup-rule ( rule parser -- rule' )
2dup rule [ 2nip ] [ no-rule ] if* ;
TUPLE: tokenizer-tuple any one many ;
: default-tokenizer ( -- tokenizer )
T{ tokenizer-tuple f
[ any-char ]
[ token ]
[ [ = ] curry any-char swap semantic ]
} ;
: parser-tokenizer ( parser -- tokenizer )
[ 1quotation ] keep
[ swap [ = ] curry semantic ] curry dup tokenizer-tuple boa ;
: rule-tokenizer ( name word -- tokenizer )
rule parser-tokenizer ;
: tokenizer ( -- word )
\ tokenizer get-global [ default-tokenizer ] unless* ;
: reset-tokenizer ( -- )
default-tokenizer \ tokenizer set-global ;
ERROR: no-tokenizer name ;
M: no-tokenizer summary
drop "Tokenizer not found" ;
SYNTAX: TOKENIZER:
scan-word-name dup search [ nip ] [ no-tokenizer ] if*
execute( -- tokenizer ) \ tokenizer set-global ;
TUPLE: ebnf-non-terminal symbol ;
TUPLE: ebnf-terminal symbol ;
TUPLE: ebnf-foreign word rule ;
TUPLE: ebnf-any-character ;
TUPLE: ebnf-range pattern ;
TUPLE: ebnf-ensure group ;
TUPLE: ebnf-ensure-not group ;
TUPLE: ebnf-choice options ;
TUPLE: ebnf-sequence elements ;
TUPLE: ebnf-ignore group ;
TUPLE: ebnf-repeat0 group ;
TUPLE: ebnf-repeat1 group ;
TUPLE: ebnf-optional group ;
TUPLE: ebnf-whitespace group ;
TUPLE: ebnf-tokenizer elements ;
TUPLE: ebnf-rule symbol elements ;
TUPLE: ebnf-action parser code ;
TUPLE: ebnf-var parser name ;
TUPLE: ebnf-semantic parser code ;
TUPLE: ebnf rules ;
C: <ebnf-non-terminal> ebnf-non-terminal
C: <ebnf-terminal> ebnf-terminal
C: <ebnf-foreign> ebnf-foreign
C: <ebnf-any-character> ebnf-any-character
C: <ebnf-range> ebnf-range
C: <ebnf-ensure> ebnf-ensure
C: <ebnf-ensure-not> ebnf-ensure-not
C: <ebnf-choice> ebnf-choice
C: <ebnf-sequence> ebnf-sequence
C: <ebnf-ignore> ebnf-ignore
C: <ebnf-repeat0> ebnf-repeat0
C: <ebnf-repeat1> ebnf-repeat1
C: <ebnf-optional> ebnf-optional
C: <ebnf-whitespace> ebnf-whitespace
C: <ebnf-tokenizer> ebnf-tokenizer
C: <ebnf-rule> ebnf-rule
C: <ebnf-action> ebnf-action
C: <ebnf-var> ebnf-var
C: <ebnf-semantic> ebnf-semantic
C: <ebnf> ebnf
: filter-hidden ( seq -- seq )
#! Remove elements that produce no AST from sequence
[ ebnf-ensure-not? ] reject [ ebnf-ensure? not ] filter ;
: syntax ( string -- parser )
#! Parses the string, ignoring white space, and
#! does not put the result in the AST.
token sp hide ;
: syntax-pack ( begin parser end -- parser )
#! Parse parser-parser surrounded by syntax elements
#! begin and end.
[ syntax ] 2dip syntax pack ;
: insert-escapes ( string -- string )
[
"\t" token [ drop "\\t" ] action ,
"\n" token [ drop "\\n" ] action ,
"\r" token [ drop "\\r" ] action ,
] choice* replace ;
: identifier-parser ( -- parser )
#! Return a parser that parses an identifer delimited by
#! a quotation character. The quotation can be single
#! or double quotes. The AST produced is the identifier
#! between the quotes.
[
[ CHAR: " = not ] satisfy repeat1 "\"" "\"" surrounded-by ,
[ CHAR: ' = not ] satisfy repeat1 "'" "'" surrounded-by ,
] choice* [ >string unescape-string ] action ;
: non-terminal-parser ( -- parser )
#! A non-terminal is the name of another rule. It can
#! be any non-blank character except for characters used
#! in the EBNF syntax itself.
[
{
[ blank? ]
[ CHAR: " = ]
[ CHAR: ' = ]
[ CHAR: | = ]
[ CHAR: { = ]
[ CHAR: } = ]
[ CHAR: = = ]
[ CHAR: ) = ]
[ CHAR: ( = ]
[ CHAR: ] = ]
[ CHAR: [ = ]
[ CHAR: . = ]
[ CHAR: ! = ]
[ CHAR: & = ]
[ CHAR: * = ]
[ CHAR: + = ]
[ CHAR: ? = ]
[ CHAR: : = ]
[ CHAR: ~ = ]
[ CHAR: < = ]
[ CHAR: > = ]
} 1|| not
] satisfy repeat1 [ >string <ebnf-non-terminal> ] action ;
: terminal-parser ( -- parser )
#! A terminal is an identifier enclosed in quotations
#! and it represents the literal value of the identifier.
identifier-parser [ <ebnf-terminal> ] action ;
: foreign-name-parser ( -- parser )
#! Parse a valid foreign parser name
[
{
[ blank? ]
[ CHAR: > = ]
} 1|| not
] satisfy repeat1 [ >string ] action ;
: foreign-parser ( -- parser )
#! A foreign call is a call to a rule in another ebnf grammar
[
"<foreign" syntax ,
foreign-name-parser sp ,
foreign-name-parser sp optional ,
">" syntax ,
] seq* [ first2 <ebnf-foreign> ] action ;
: any-character-parser ( -- parser )
#! A parser to match the symbol for any character match.
[ CHAR: . = ] satisfy [ drop <ebnf-any-character> ] action ;
: range-parser-parser ( -- parser )
#! Match the syntax for declaring character ranges
[
[ "[" syntax , "[" token ensure-not , ] seq* hide ,
[ CHAR: ] = not ] satisfy repeat1 ,
"]" syntax ,
] seq* [ first >string unescape-string <ebnf-range> ] action ;
: (element-parser) ( -- parser )
#! An element of a rule. It can be a terminal or a
#! non-terminal but must not be followed by a "=".
#! The latter indicates that it is the beginning of a
#! new rule.
[
[
[
non-terminal-parser ,
terminal-parser ,
foreign-parser ,
range-parser-parser ,
any-character-parser ,
] choice*
[ dup , "~" token hide , ] seq* [ first <ebnf-ignore> ] action ,
[ dup , "*" token hide , ] seq* [ first <ebnf-repeat0> ] action ,
[ dup , "+" token hide , ] seq* [ first <ebnf-repeat1> ] action ,
[ dup , "?[" token ensure-not , "?" token hide , ] seq* [ first <ebnf-optional> ] action ,
,
] choice* ,
[
"=" syntax ensure-not ,
"=>" syntax ensure ,
] choice* ,
] seq* [ first ] action ;
DEFER: action-parser
: element-parser ( -- parser )
[
[
(element-parser) , ":" syntax ,
"a-zA-Z_" range-pattern
"a-zA-Z0-9_-" range-pattern repeat1 2seq [ first2 swap prefix >string ] action ,
] seq* [ first2 <ebnf-var> ] action ,
(element-parser) ,
] choice* ;
DEFER: choice-parser
: grouped ( quot suffix -- parser )
#! Parse a group of choices, with a suffix indicating
#! the type of group (repeat0, repeat1, etc) and
#! an quot that is the action that produces the AST.
2dup
[
"(" [ choice-parser sp ] delay ")" syntax-pack
swap 2seq
[ first ] rot compose action ,
"{" [ choice-parser sp ] delay "}" syntax-pack
swap 2seq
[ first <ebnf-whitespace> ] rot compose action ,
] choice* ;
: group-parser ( -- parser )
#! A grouping with no suffix. Used for precedence.
[ ] [
"~" token sp ensure-not ,
"*" token sp ensure-not ,
"+" token sp ensure-not ,
"?" token sp ensure-not ,
] seq* hide grouped ;
: ignore-parser ( -- parser )
[ <ebnf-ignore> ] "~" syntax grouped ;
: repeat0-parser ( -- parser )
[ <ebnf-repeat0> ] "*" syntax grouped ;
: repeat1-parser ( -- parser )
[ <ebnf-repeat1> ] "+" syntax grouped ;
: optional-parser ( -- parser )
[ <ebnf-optional> ] "?" syntax grouped ;
: factor-code-parser ( -- parser )
[
"]]" token ensure-not ,
"]?" token ensure-not ,
[ drop t ] satisfy ,
] seq* repeat0 [ "" concat-as ] action ;
: ensure-not-parser ( -- parser )
#! Parses the '!' syntax to ensure that
#! something that matches the following elements do
#! not exist in the parse stream.
[
"!" syntax ,
group-parser sp ,
] seq* [ first <ebnf-ensure-not> ] action ;
: ensure-parser ( -- parser )
#! Parses the '&' syntax to ensure that
#! something that matches the following elements does
#! exist in the parse stream.
[
"&" syntax ,
group-parser sp ,
] seq* [ first <ebnf-ensure> ] action ;
: (sequence-parser) ( -- parser )
#! A sequence of terminals and non-terminals, including
#! groupings of those.
[
[
ensure-not-parser sp ,
ensure-parser sp ,
element-parser sp ,
group-parser sp ,
ignore-parser sp ,
repeat0-parser sp ,
repeat1-parser sp ,
optional-parser sp ,
] choice*
[ dup , ":" syntax , "a-zA-Z" range-pattern repeat1 [ >string ] action , ] seq* [ first2 <ebnf-var> ] action ,
,
] choice* ;
: action-parser ( -- parser )
"[[" factor-code-parser "]]" syntax-pack ;
: semantic-parser ( -- parser )
"?[" factor-code-parser "]?" syntax-pack ;
: sequence-parser ( -- parser )
#! A sequence of terminals and non-terminals, including
#! groupings of those.
[
[ (sequence-parser) , action-parser , ] seq*
[ first2 <ebnf-action> ] action ,
[ (sequence-parser) , semantic-parser , ] seq*
[ first2 <ebnf-semantic> ] action ,
(sequence-parser) ,
] choice* repeat1 [
dup length 1 = [ first ] [ <ebnf-sequence> ] if
] action ;
: actioned-sequence-parser ( -- parser )
[
[ sequence-parser , "=>" syntax , action-parser , ] seq*
[ first2 <ebnf-action> ] action ,
sequence-parser ,
] choice* ;
: choice-parser ( -- parser )
actioned-sequence-parser sp repeat1 [
dup length 1 = [ first ] [ <ebnf-sequence> ] if
] action "|" token sp list-of [
dup length 1 = [ first ] [ <ebnf-choice> ] if
] action ;
: tokenizer-parser ( -- parser )
[
"tokenizer" syntax ,
"=" syntax ,
">" token ensure-not ,
[ "default" token sp , choice-parser , ] choice* ,
] seq* [ first <ebnf-tokenizer> ] action ;
: rule-parser ( -- parser )
[
"tokenizer" token ensure-not ,
non-terminal-parser [ symbol>> ] action ,
"=" syntax ,
">" token ensure-not ,
choice-parser ,
] seq* [ first2 <ebnf-rule> ] action ;
: ebnf-parser ( -- parser )
[ tokenizer-parser sp , rule-parser sp , ] choice* repeat1 [ <ebnf> ] action ;
GENERIC: (transform) ( ast -- parser )
SYMBOL: parser
SYMBOL: main
SYMBOL: ignore-ws
: transform ( ast -- object )
H{ } clone dup dup [
f ignore-ws set
parser set
swap (transform)
main set
] with-variables ;
M: ebnf (transform) ( ast -- parser )
rules>> [ (transform) ] map last ;
M: ebnf-tokenizer (transform) ( ast -- parser )
elements>> dup "default" = [
drop default-tokenizer \ tokenizer set-global any-char
] [
(transform)
dup parser-tokenizer \ tokenizer set-global
] if ;
ERROR: redefined-rule name ;
M: redefined-rule summary
name>> "Rule '" "' defined more than once" surround ;
M: ebnf-rule (transform) ( ast -- parser )
dup elements>>
(transform) [
swap symbol>> dup get parser? [ redefined-rule ] [ set ] if
] keep ;
M: ebnf-sequence (transform) ( ast -- parser )
#! If ignore-ws is set then each element of the sequence
#! ignores leading whitespace. This is not inherited by
#! subelements of the sequence.
elements>> [
f ignore-ws [ (transform) ] with-variable
ignore-ws get [ sp ] when
] map seq [ dup length 1 = [ first ] when ] action ;
M: ebnf-choice (transform) ( ast -- parser )
options>> [ (transform) ] map choice ;
M: ebnf-any-character (transform) ( ast -- parser )
drop tokenizer any>> call( -- parser ) ;
M: ebnf-range (transform) ( ast -- parser )
pattern>> range-pattern ;
: transform-group ( ast -- parser )
#! convert a ast node with groups to a parser for that group
group>> (transform) ;
M: ebnf-ensure (transform) ( ast -- parser )
transform-group ensure ;
M: ebnf-ensure-not (transform) ( ast -- parser )
transform-group ensure-not ;
M: ebnf-ignore (transform) ( ast -- parser )
transform-group [ drop ignore ] action ;
M: ebnf-repeat0 (transform) ( ast -- parser )
transform-group repeat0 ;
M: ebnf-repeat1 (transform) ( ast -- parser )
transform-group repeat1 ;
M: ebnf-optional (transform) ( ast -- parser )
transform-group optional ;
M: ebnf-whitespace (transform) ( ast -- parser )
t ignore-ws [ transform-group ] with-variable ;
GENERIC: build-locals ( code ast -- code )
M: ebnf-sequence build-locals ( code ast -- code )
#! Note the need to filter out this ebnf items that
#! leave nothing in the AST
elements>> filter-hidden dup length 1 = [
first build-locals
] [
dup [ ebnf-var? ] any? not [
drop
] [
[
"FROM: locals => [let :> ; FROM: sequences => nth ; FROM: kernel => nip over ; [let " %
[
over ebnf-var? [
" " % # " over nth :> " %
name>> %
] [
2drop
] if
] each-index
" " %
%
" nip ]" %
] "" make
] if
] if ;
M: ebnf-var build-locals ( code ast -- code )
[
"FROM: locals => [let :> ; FROM: kernel => dup nip ; [let " %
" dup :> " % name>> %
" " %
%
" nip ]" %
] "" make ;
M: object build-locals ( code ast -- code )
drop ;
ERROR: bad-effect quot effect ;
: check-action-effect ( quot -- quot )
dup infer {
{ [ dup ( a -- b ) effect<= ] [ drop ] }
{ [ dup ( -- b ) effect<= ] [ drop [ drop ] prepose ] }
[ bad-effect ]
} cond ;
: ebnf-transform ( ast -- parser quot )
[ parser>> (transform) ]
[ code>> insert-escapes ]
[ parser>> ] tri build-locals
string-lines parse-lines ;
M: ebnf-action (transform) ( ast -- parser )
ebnf-transform check-action-effect action ;
M: ebnf-semantic (transform) ( ast -- parser )
ebnf-transform semantic ;
M: ebnf-var (transform) ( ast -- parser )
parser>> (transform) ;
M: ebnf-terminal (transform) ( ast -- parser )
symbol>> tokenizer one>> call( symbol -- parser ) ;
ERROR: ebnf-foreign-not-found name ;
M: ebnf-foreign-not-found summary
name>> "Foreign word '" "' not found" surround ;
M: ebnf-foreign (transform) ( ast -- parser )
dup word>> search [ word>> ebnf-foreign-not-found ] unless*
swap rule>> [ main ] unless* over rule [
nip
] [
execute( -- parser )
] if* ;
ERROR: parser-not-found name ;
M: ebnf-non-terminal (transform) ( ast -- parser )
symbol>> [
, \ dup , parser get , \ at ,
[ parser-not-found ] , \ unless* , \ nip ,
] [ ] make box ;
: transform-ebnf ( string -- object )
ebnf-parser parse transform ;
ERROR: unable-to-fully-parse-ebnf remaining ;
ERROR: could-not-parse-ebnf ;
: check-parse-result ( result -- result )
[
dup remaining>> [ blank? ] trim [
unable-to-fully-parse-ebnf
] unless-empty
] [
could-not-parse-ebnf
] if* ;
: parse-ebnf ( string -- hashtable )
ebnf-parser (parse) check-parse-result ast>> transform ;
: ebnf>quot ( string -- hashtable quot )
parse-ebnf dup dup parser [ main of compile ] with-variable
[ compiled-parse ] curry [ with-scope ast>> ] curry ;
PRIVATE>
SYNTAX: <EBNF
"EBNF>"
reset-tokenizer parse-multiline-string parse-ebnf main of
suffix! reset-tokenizer ;
SYNTAX: [EBNF
"EBNF]"
reset-tokenizer parse-multiline-string ebnf>quot nip
suffix! \ call suffix! reset-tokenizer ;
SYNTAX: EBNF:
reset-tokenizer scan-new-word dup ";EBNF" parse-multiline-string
ebnf>quot swapd
( input -- ast ) define-declared "ebnf-parser" set-word-prop
reset-tokenizer ;