[antlr-interest] How do I specify start-of-line (^ in [F]Lex in ANTLR Lexers?

[Terence Parr]

On Monday, May 27, 2002, at 08:37  AM, Greg Lindholm wrote:

> ANTLR doesn't have a way of specifing start-of-line as part of a rule.
> Once you have entered a rule you can use a sematic predicate to check
> what column your at, but this probably doesn't help you.
>
> IMHO ANTLR is not well suited for writing a preprocessor as;
> 1) Preprocessors are line-oriented and ANTLR isn't.
> 2) The output of an ANTLR lexer is a token stream where the
> output of a preprocessor is a character stream (or file) that
> then gets fed into a lexer.

Very good points...

Here is a strategy that you may not have considered: do a line oriented 
loop to get input and then when you find a directive in column one, use 
ANTLR to lex or parse just that line :)  Works great.

Ter


 

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