[antlr-interest] newbie: tokens and lexer rules
JConner at ssp-uk.com
JConner at ssp-uk.com
Tue Aug 2 06:52:09 PDT 2005
Hello!
To help myself to learn antlr, I'm playing around with a grammer (fgl.g).
I'm trying to get to grips with parser rules, lexer rules, tokens, and the
like.
I've come accross a parser rule that contains a mixture of rule references
and tokens:
functionIdentifier
: DAY
| YEAR
<many more tokens>
| constantIdentifier
;
So that I can easily add actions to get the text of the token, I thought
I'd be clever and bunch the tokens up in a lexer rule, then reference this
from the parser rule:
functionIdentifier
: MY_STUFF
| constantIdentifier
;
(and in the lexer)
MY_STUFF
: DAY
| YEAR
<more>
;
When I try to compile this, I get errors about lexer rules for DAY, YEAR,
etc not being defined. I thought I could use tokens in lexer rules...?
Can anyone point out the obvious issue that I'm missing?
John
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