[antlr-interest] BUG - Antlr is snooping in comments

[Austin Hastings]

/* There's a comment here, too. */
scope    Mumble {
    int        foo;    /* Comment at the end? (x = 1) */
}



After scratching my head for a while over a mysterious error message, I 
finally got the example case above.

 From what I can tell, ANTLR treats the curly braces as delimiting some 
mysterious other language -- this is decent, since it is trying to be 
language-agnostic. But the error message is a killer:

   [antlr3] error(148): 
/home/austin/parrot/languages/hlasm/lib/grammar/HlasmSyntax.g:60:14: 
rule parameters may not have init values: x

It took a while for me to understand what the problem was: apparently 
ANTLR is not *totally* ignoring what happens inside the curlies. It is 
trying to make sure that no initializers are provided -- possibly 
indicating that this was (or still is) a common problem. But it is going 
about it by looking for something like /\w+ =/ in the block, and 
generating an error if it is found.

For me this has translated into "you may not use equal sign in comments 
inside a scope block," which is amusing and annoying at the same time. I 
submit that when this kind of thing is found, it should be a warning 
rather than an error.

Or maybe antlr needs a tuneable warning / error system.

=Austin