[antlr-interest] Selective ignoring of whitespace
Micha
micha-1 at fantasymail.de
Thu May 14 12:21:47 PDT 2009
On Thursday 14 May 2009 19:02:56 Ratul Bhadury wrote:
> Hello all,
>
> I've been trying to achieve something using Antlr v3, but have been
> struggling for a while now, and think its now time to ask the help of more
> experienced users, hence this mail.
>
> What I basically want to achieve is a simple parser which will accept lines
> of the nature:
>
> sec = <keyword>
>
> I want any whitespace (spaces and tabs) before the '=' sign to be ignored,
> but any spaces after '=' to be included in what will be regarded as the
> keyword. Therefore:
> sec= hello -> is valid
> sec =hello people -> is valid
> sec = hello -> is valid
> se= hello -> is rejected
something like this? (this read only one clause),
KEYWORD includes the whitespace at the beginning, but not at the end.
grammar Key;
start : clause EOF;
clause : SECURITY KEYWORD WS* ;
fragment WS : ' ' | '\t';
fragment NUMBER : ('0' .. '9')+;
fragment WORD : ('a' .. 'z')+;
SECURITY : ('S'|'s')('E'|'e')('C'|'c') WS* '=' ;
KEYWORD : WS* (WORD | NUMBER);
cheers,
Michael
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