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EBNF syntax change 

[ ... ] is now ( ... )?
{ ... } is now ( ... )*
Added ( ... )+
db4
Chris Double 2008-03-20 01:18:09 +13:00
parent 64135b73e1
commit 82d54d3776
2 changed files with 27 additions and 11 deletions
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4
extra/peg/ebnf/ebnf-tests.factor
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@ -83,7 +83,7 @@ IN: peg.ebnf.tests
} }
} }
} [ } [
"one {(two | three) four}" 'choice' parse parse-result-ast "one ((two | three) four)*" 'choice' parse parse-result-ast
] unit-test ] unit-test
{ {
@ -95,7 +95,7 @@ IN: peg.ebnf.tests
} }
} }
} [ } [
"one [ two ] three" 'choice' parse parse-result-ast "one ( two )? three" 'choice' parse parse-result-ast
] unit-test ] unit-test
{ "foo" } [ { "foo" } [

34
extra/peg/ebnf/ebnf.factor
View File

@ -12,6 +12,7 @@ TUPLE: ebnf-ensure-not group ;
TUPLE: ebnf-choice options ; TUPLE: ebnf-choice options ;
TUPLE: ebnf-sequence elements ; TUPLE: ebnf-sequence elements ;
TUPLE: ebnf-repeat0 group ; TUPLE: ebnf-repeat0 group ;
TUPLE: ebnf-repeat1 group ;
TUPLE: ebnf-optional elements ; TUPLE: ebnf-optional elements ;
TUPLE: ebnf-rule symbol elements ; TUPLE: ebnf-rule symbol elements ;
TUPLE: ebnf-action word ; TUPLE: ebnf-action word ;
@ -24,6 +25,7 @@ C: <ebnf-ensure-not> ebnf-ensure-not
C: <ebnf-choice> ebnf-choice C: <ebnf-choice> ebnf-choice
C: <ebnf-sequence> ebnf-sequence C: <ebnf-sequence> ebnf-sequence
C: <ebnf-repeat0> ebnf-repeat0 C: <ebnf-repeat0> ebnf-repeat0
C: <ebnf-repeat1> ebnf-repeat1
C: <ebnf-optional> ebnf-optional C: <ebnf-optional> ebnf-optional
C: <ebnf-rule> ebnf-rule C: <ebnf-rule> ebnf-rule
C: <ebnf-action> ebnf-action C: <ebnf-action> ebnf-action
@ -84,6 +86,9 @@ M: ebnf-ensure-not (generate-parser) ( ast -- id )
M: ebnf-repeat0 (generate-parser) ( ast -- id ) M: ebnf-repeat0 (generate-parser) ( ast -- id )
ebnf-repeat0-group generate-parser get-parser repeat0 store-parser ; ebnf-repeat0-group generate-parser get-parser repeat0 store-parser ;
M: ebnf-repeat1 (generate-parser) ( ast -- id )
ebnf-repeat1-group generate-parser get-parser repeat1 store-parser ;
M: ebnf-optional (generate-parser) ( ast -- id ) M: ebnf-optional (generate-parser) ( ast -- id )
ebnf-optional-elements generate-parser get-parser optional store-parser ; ebnf-optional-elements generate-parser get-parser optional store-parser ;
@ -176,20 +181,30 @@ DEFER: 'rhs'
DEFER: 'choice' DEFER: 'choice'
: grouped ( begin quot end -- parser ) : grouped ( quot suffix -- parser )
#! Parse a group of choices, where the delimiter for the #! Parse a group of choices, with a suffix indicating
#! group is specified by 'begin' and 'end'. The quotation #! the type of group (repeat0, repeat1, etc) and
#! should produce the AST to be the result of the parser. #! an quot that is the action that produces the AST.
[ [ 'choice' sp ] delay swap action ] dip syntax-pack ; "(" [ 'choice' sp ] delay ")" syntax-pack
swap 2seq
[ first ] rot compose action ;
: 'group' ( -- parser ) : 'group' ( -- parser )
"(" [ ] ")" grouped ; #! A grouping with no suffix. Used for precedence.
[ ] [
"*" token sp ensure-not ,
"+" token sp ensure-not ,
"?" token sp ensure-not ,
] seq* hide grouped ;
: 'repeat0' ( -- parser ) : 'repeat0' ( -- parser )
"{" [ <ebnf-repeat0> ] "}" grouped ; [ <ebnf-repeat0> ] "*" syntax grouped ;
: 'repeat1' ( -- parser )
[ <ebnf-repeat1> ] "+" syntax grouped ;
: 'optional' ( -- parser ) : 'optional' ( -- parser )
"[" [ <ebnf-optional> ] "]" grouped ; [ <ebnf-optional> ] "?" syntax grouped ;
: 'ensure-not' ( -- parser ) : 'ensure-not' ( -- parser )
#! Parses the '!' syntax to ensure that #! Parses the '!' syntax to ensure that
@ -208,6 +223,7 @@ DEFER: 'choice'
'element' sp , 'element' sp ,
'group' sp , 'group' sp ,
'repeat0' sp , 'repeat0' sp ,
'repeat1' sp ,
'optional' sp , 'optional' sp ,
] choice* repeat1 [ ] choice* repeat1 [
dup length 1 = [ first ] [ <ebnf-sequence> ] if dup length 1 = [ first ] [ <ebnf-sequence> ] if