[lug] Perl question: how to print embedded metacharacters

[Tkil]

>>>>> "Chip" == Chip Atkinson <chip at pupman.com> writes:

Chip> The most important thing is speed since the files are rather
Chip> huge.  I think I'll implement the regex/hash approach tomorrow.

Curious how it worked out.

A good reason to use 'eval' directly is if you want to write your
entire configuration file in perl itself.  (I'm pretty sure this is
what Rob is doing.)

That has some advantages:

 * speed of parsing (relative to reading each line in perl, splitting
   it however you need to, doing substitutions, and then stuffing it
   in a data structure somewhere);

 * precision (can specify whitespace and other special characters very
   precisely if necessary);

 * completeness (it /is/ perl, so you can represent any structure you
   need to);

 * can be trivially rewritten (using Data::Dumper if nothing else).

But there are disadvantages:

 * editing the config in any non-trivial manner requires learning
   perl, which is a non-trivial language (and config files would have
   more obtuse corners than most).

 * if the files aren't entirely under your control, you open your
   application up to attacks (similar in nature to sql injection
   attacks, as mentioned in my reply to Rob).

There are some competing technologies here.  Obviously, XML works for
interchange to non-Perl solutions; if you're staying within Perl,
there was a lot of excitement over YAML a few years back as a more
"human friendly" option.

There is the Windows-style INI file, and there are modules that parse
those for Perl.

And then there's "roll your own".

We don't know all your constraints and preferences, so we can't say
what's the right answer.  If your config files are "huge", however,
I'm guessing that they're derived from (or lightly-edited versions of)
some other file, so switching to pure perl for config seems unlikely,
as is the switch to any other markup language.

So you're left with "roll your own" ... just make sure you define your
own markup in a clean way!

Good luck,
t.