[antlr-interest] How to handle first non whitespace comment characters?

Jim Loverde loverde at nvisia.com
Wed Jun 13 01:20:22 PDT 2007


Hello,

I was hoping someone could help me out, as I've been struggling with this for a bit.  Basically, how do you handle something like a COBOL asterisk comment character, where it is only a valid line comment indicator if it is the first non whitespace character on a line (but if it's part of an expression such as 5 * 7 it shouldn't be treated as a line comment character).

For example:

* This is a line comment
IF 5 * 5 = 20 THEN
    * this is also a line comment
    NOTHING
END-IF.

Ideally I'd like to have the line comments channeled to the hidden channel similar to the "normal" line comment such as:

LINE_COMMENT
    :    '!' ~('\n'|'\r')*  '\r'? '\n' {$channel=HIDDEN;}

Also, while on the topic, does anyone have a COBOL grammar for ANTLR (or even a partial grammar) that they can share?

Thanks in advance for any help.




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