[antlr-interest] newbie: lexer rules vs parser rules

[Dieter Frej]

ok, even though I might look like a total newbie I have to ask that:
Are there any rule of thumb on how to decide what a literal is and what
a rule is? (respectively what goes into the parser and what into the
lexer?)

Digits:
Digit
Digits Digit

Digit:
0
NonZeroDigit

NonZeroDigit: one of
1 2 3 4 5 6 7 8 9

I would say NonZeroDigit is a literal and goes into the lexer, right?
What about the other two? Should both go into the parser?

- Didi



Terence Parr wrote:
> 
> On May 18, 2006, at 12:54 AM, <JConner at ssp-uk.com> <JConner at ssp-uk.com> 
> wrote:
> 
>> Hi All,
>>
>> I've started to get my feet wet with ANTLR a little, and I've come 
>> across a
>> few things that I thought would be handled by lexer rules, but seem to be
>> handled in general by parser rules.  For example, most of the examples 
>> I've
>> seen handle numbers (floating, exponents, sign, etc) with parser rules,
> 
> Those should be lexer rules...most places I've seen.  Remember FLOAT 
> means lexer rule :)
> 
> Ter
> 
>