Hi,
I'm working on a grammar and I can't figure out how to refactor it without
using semantic predicates. Essentially, what I'm trying to do with RAW_TEXT is
a catch all if none of the tags match, the only way I could make it work was by
using Semantic Predicates, does anyone have ideas? Thanks in advance. The
problem is that I need { tokens to be parsed as RAW_TEXT if they do not match
the other tag types.
Brian
grammar Dust;
options {
language=Java;
output=AST;
ASTLabelType=CommonTree;
}
/* LEXER RULES */
tokens {
TAG;
SPECIAL_TAG;
LOOP_SECTION;
EXISTS_SECTION;
NOT_EXISTS_SECTION;
CONTEXT_HELPER_SECTION;
INLINE_PARTIAL_SECTION;
PRAGMA_SECTION;
CUSTOM_SECTION;
BLOCK_SECTION;
END_SECTION;
PARTIAL;
BUFFER;
COMMENT;
QUOTED_PARAM;
IDENT_PARAM;
CONTEXT;
SEC_START_TAG;
SEC_END_TAG;
BODY;
IDENT;
FILTER;
ELSE_BODY;
CUSTOM_BLK;
SELF_CLOSE;
}
@lexer::members{
boolean inTag = false;
}
/* LEXER RULES */
COMMENT_T : '{!' .* '!}';
ID : { inTag }? => (LETTER | '_' | '$') (LETTER | '_' | DIGIT | '$')*;
IDENTIFIER : (('.'? ID ('.' ID)*));
RAW_TEXT : { !inTag }? => ~('{'|'}')+;
fragment DIGIT : '0'..'9';
fragment LETTER : ('a'..'z' | 'A'..'Z');
LD @init { inTag = true; } : '{' ;
RD @init { inTag = false; } : '}' ;
QUOTED_STR : { inTag }? => '"' ~('\n' | '\r' | '"')* '"';
/* DUST PARSER RULES */
start : body? EOF
;
body : ( tag
| special_tag
| section
| partial
| comment
| buffer )+
;
buffer
: RAW_TEXT -> ^(BUFFER RAW_TEXT)
;
ident : IDENTIFIER -> ^(IDENT IDENTIFIER)
| ID -> ^(IDENT ID)
| '.' -> ^(IDENT '.')
;
special_tag
: LD '~' ID RD -> ^(SPECIAL_TAG ID)
;
filter
: '|' ID -> ^(FILTER ID)
;
tag
: LD ident filter* RD -> ^(TAG ident filter*)
;
parameter
: ' ' i1=ident '=' ( QUOTED_STR -> ^(QUOTED_PARAM $i1 QUOTED_STR)
| i2=ident -> ^(IDENT_PARAM $i1 $i2) )
;
context
: ':' ident -> ^(CONTEXT ident)
;
partial
: LD '>' ident context? '/' RD -> ^(PARTIAL ident context?)
;
section_start_tag
: ident context? parameter* -> ^(SEC_START_TAG ident context?
parameter*)
;
section_end_tag
: LD '/' ident RD -> ^(SEC_END_TAG ident)
;
else_section
: ( LD ':else' RD body? ) -> ^(ELSE_BODY body?)
;
loop_section
: LD '#' section_start_tag RD
body?
else_section?
section_end_tag -> ^(LOOP_SECTION section_start_tag ^(BODY body?)
else_section? section_end_tag)
| LD '#' section_start_tag '/' RD -> ^(LOOP_SECTION
section_start_tag SELF_CLOSE)
;
exists_section
: LD '?' section_start_tag RD
body?
else_section?
section_end_tag -> ^(EXISTS_SECTION section_start_tag ^(BODY
body?) else_section? section_end_tag)
| LD '?' section_start_tag '/' RD -> ^(EXISTS_SECTION
section_start_tag SELF_CLOSE)
;
not_exists_section
: LD '^' section_start_tag RD
body?
else_section?
section_end_tag -> ^(NOT_EXISTS_SECTION section_start_tag ^(BODY
body?) else_section? section_end_tag)
| LD '^' section_start_tag '/' RD -> ^(NOT_EXISTS_SECTION
section_start_tag SELF_CLOSE)
;
context_helper_section
: LD '@' section_start_tag RD
body?
section_end_tag -> ^(CONTEXT_HELPER_SECTION section_start_tag
^(BODY body?) section_end_tag)
| LD '@' section_start_tag '/' RD -> ^(CONTEXT_HELPER_SECTION
section_start_tag SELF_CLOSE)
;
pragma_section
: LD '%' section_start_tag RD
body?
section_end_tag -> ^(PRAGMA_SECTION section_start_tag ^(BODY
body?) section_end_tag)
| LD '%' section_start_tag '/' RD -> ^(PRAGMA_SECTION
section_start_tag SELF_CLOSE)
;
block_section
: LD '+' section_start_tag RD
body?
section_end_tag -> ^(BLOCK_SECTION section_start_tag ^(BODY
body?) section_end_tag)
| LD '+' section_start_tag '/' RD -> ^(BLOCK_SECTION
section_start_tag SELF_CLOSE)
;
inline_partial_section
: LD '<' section_start_tag RD
body?
section_end_tag -> ^(INLINE_PARTIAL_SECTION section_start_tag
^(BODY body?) section_end_tag)
| LD '<' section_start_tag '/' RD -> ^(INLINE_PARTIAL_SECTION
section_start_tag SELF_CLOSE)
;
custom_section
: LD '*' section_start_tag '/' RD -> ^(CUSTOM_SECTION
section_start_tag SELF_CLOSE)
;
section
: loop_section
| exists_section
| not_exists_section
| context_helper_section
| pragma_section
| block_section
| inline_partial_section
| custom_section
;
comment
: COMMENT_T -> ^(COMMENT COMMENT_T)
;
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