[DGD] comments in parse_string() grammars?

[Erwin Harte]

On Tue, Mar 25, 2003 at 09:10:19PM -0800, Keith Dunwoody wrote:
> Is there any way of putting a comment in a
> parse_string() grammar?

No, this is a typical case of DGD's bare bones approach, you are
encouraged to write a wrapper that strips out the comments (whichever
commenting style you prefer) and present the stripped grammar to the
actual parse_string() kfun.

This also gives you the opportunity to do other conversions if you so
desire, like embedding LPC code into the grammar that you detect and
deal with appropriately.

This could be as simple as this (warning: uncompiled/untested code):

    mixed *
    parse_string(string grammar, string str, varargs int alternatives)
    {
        int i, sz;
        string *lines;

        lines = explode(grammar, "\n");
        for (i = 0, sz = sizeof(lines); i < sz; i++) {
            if (lines[i] && strlen(lines[i]) && lines[i][0] == '#') {
                lines[i] = nil;
            }
        }
        return ::parse_string(implode(lines, "\n"), str, alternatives);
    }

Hope that helps,

Erwin.
-- 
Erwin Harte <harte at xs4all.nl>
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