Difficulty with character having special meaning after new line

[Peter Frazer]

I am trying to define a grammar in which the character '*' starts a line comment if it is the first character on a line and am having difficult distinguishing it from a multiply symbol (also '*' but never at start of line).

I am currently using GOLD Parser Builder 3.0.1 as I have some problems with the new .egt format.  I found a comment in the documentation about 'older grammars using regular expressions to define comments' but I could not figure out how to do it.  I tried a variety of things like {CR}'*' but whatever I try I get an error either in building the grammar or in parsing.

The '*' could also start a comment at the very beginning of the file.

Any suggestions greatly appreciated.

Peter.

[Devin Cook]

Are you parsing COBOL? Are new-lines significant in the grammar? In
may older language like COBOL and FORTRAN, they use a preprocesser
that removes these lines before the text is parsed.

- Devin Cook

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[Peter Frazer]

Thank you Devin,

I was considering custom code in the lexer to deal with this and I guess that is what I need to do.  But a grammar based approach seemed more elegant.

As a matter of interest is it / was it possible to use regular expressions in the definition of comments and if so how? 

I still haven't completely found my way around the documentation, is there a master index to all pages somewhere?

Peter.

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[Devin Cook]

The documentation, on the site, is pretty lacking... :(

In this case, it seems that the grammar is context-sensitive. The
location of the asterisk, on the screen, impacts how it is viewed. It
will probably be easier to write a simple preprocessor that removes
the commented lines. The resulting temporary file can be fed to the
parser.

Have a great day,

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