[Boulder.pm] Trickey (for a newbie) String Replacement

[Luke Palmer]

Peter Hutnick writes:
> Hello,
> 
> I'm writing a little script to do some of the grunt-work of converting a 
> LaTeX document to XHTML.
> 
> Consider the following block of code:
> 
> @rule=( 's/\\emph{(.*?)}/\<em\>$1\<\/em\>/g',
>         's/\\chapter{(.*)}/\<h1\>$1\<\/h1\>/g');
> 
>         foreach (@rule) {
> print $_, ";\n";
>                 $text =~ $_;
>         }
> 
> As, I'm sure you can see, this does nothing.  I think you can also see 
> what I am driving at.

You had me staring at this for five minutes wondering why it didn't
work.  I completely missed the fact that you didn't have an eval.
Here's what you want (note that I fixed your regexes a little, too):

    @rule = (
        's[\\\\emph{(.*?)}]    [<em>$1</em>]g',
        's[\\\\chapter{(.*?)}] [<h1>$1</h1>]g',
        );

    # this only works if the text is in $_
    # you might have to do a little BS to get it there
    foreach my $rule (@rule) {
        eval $rule;
    }

But I'm sure someone's written a LaTeX to XHTML converter before.  Do a
little searching around (or mabye you have).

I'd also suggest using Parse::RecDescent if you want this to scale, or
if you plan on using this on multiple documents in the future.  LaTeX
has a heirarchial structure, and Perl 5's regexes don't work very well
with that.

Luke