[antlr-interest] Re: Newbie needing parser help

[lgcraymer]

Ugly problem.  What might make sense for this one is to make state
changes in the lexer and recognize strings in your COMMA rule.

That is:

ID :
   <character tokens>
   { hash table lookup; set commaText var if appropriate }
   ;


COMMA :
    { commaText = true }? ','! (~(',' | '\n'))+
        { _ttype = COMMATEXT; }
    |   ','
    ;

You can probably also do something with a token filter.

--Loring

--- In antlr-interest at yahoogroups.com, "craigbarker1"
<craigbarker1 at y...> wrote:
> Hi All,
> 
> I'm relatively new to all this language recognition stuff and have a 
> question that I could really use a hand with. It's probably not that 
> hard, it's more likely that i'm just missing something obvious.
> 
> The issue is that i'm trying to parse a language that allows 
> unquoted strings to be passed as parameters to functions. There are 
> no rules on what can go inside these unquoted string's - they can be 
> the names of literals, functions or any random sequence of 
> characters.
> 
> I've tried recognising a set of ID tokens (defined as per the java 
> grammer specification) but this is no good as i've got 
> testLiterals=true; so anything that is a literal comes through from 
> the lexer as a specific token type and therefore doesn't match 
> against ID.
> 
> Here is an example of the type of thing i'm trying to match:
> 
> PAGES,Sale detail,Status changes,Sale costs
> 
> The issue lies with the fact that each of the parameters are REALLY 
> strings but in this bizzare language they don't have to be double 
> quoted. The issue is further compounded by the fact that the word 
> Status is really a function name and hence has a specific token type.
> 
> Here is a snippet of the grammer i've done so far to deal with 
> this:
> 
> designerCommand
> //Commands to the designer
> 	:	"SIZE" COMMA NUM_INT COMMA NUM_INT
> 	|	"PAGES" COMMA textParameter (COMMA textParameter)*
> 	;
> 
> textParameter
> 	:	(ID)*
> 	| 	STRING_LITERAL
> 	;
> 
> Please let me know if you can provide any advise at all or even 
> point me to a relevant article somewhere.
> 
> Many thanks in advance,
> 
> Craig



 
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