[antlr-interest] Problems parsing numbers

[Austin Hastings]

You are saying $c...$, but the LITERAL is supposed to be DIGIT+ which 
doesn't include 'c'. What do you expect to happen for that input?

=Austin

Bolek Vrany wrote:
> Hello,
>
> I'm using ANTLR for just a few days. I need to parse a language that has
> numerical literals enclosed in $$ like $3.14$. It also allows
> identifiers to start with a digit, so 017 is a valid identifier. I
> started with creating the grammar
>
> grammar Test;
>
> rule    :    expr+;
>
> expr    :    LITERAL
>     |     VALFEATID
>     |     PAD
>     ;
>
> //condition    :    // A single condition
> //            (VALFEATID | LONGFEATID) ('=' | '>' | '>=' | '<' | '<=' 
> | '<>')
> (VALFEATID | LONGFEATID | LITERAL | PAD);
>
> fragment    // Any character allowed in identifiers
> IDCHAR    :    ('a'..'z'|'A'..'Z'|'_'|'0'..'9');
>
> VALFEATID    :    // Value or short form feature id. It can be either 
> a number
> or an alphanumeric sequence
>             IDCHAR+ ;
>        
> //LONGFEATID  :    // Long form of feature reference, type 01[A].C3G
> //        IDCHAR IDCHAR '[' ('A' | 'P' | 'B' | 'E' | 'C' | 'I' | 'L' | 
> 'S')
> '].' VALFEATID ;
>
> fragment       
> DIGIT    :     '0'..'9';
>
> LITERAL    :     // This is the numerical literal
>         '$' DIGIT+ '$'
>     |    '$' DIGIT+ '.' DIGIT+ '$'
>     ;
>     
> PAD    :    '{PAD}';   
>     
> // Newline and whitespace   
> NEWLINE    :    '\r'? '\n' ;
> WS      :    (' '|'\t'|'\n'|'\r')+ {skip();} ;
>     
> but I got into problems. When I try to parse $c12345.67890" and try to
> interpret it inside ANTLRWorks, I end up with a rule having two
> expressions, the first being $c12345 and the other one .67890 I don't
> know why.
>
> I also tried to copy the first example in The definitive ANTLR reference
> book and it behaved much like this but somehow miraculously stopped to
> at once. Don't know if it is an installation issue.
>
> I use ANTLR 3.0.1, ANTRLWorks 1.1.3, StringTemplate 3.1b1, XJLibrary 2.0
> and Java 1.6.0_03.
>
> Thanks for your help in advance
>
>
>