I do most of my perl coding using CPerl mode for Xemacs, and although it is very good at spotting syntax it is often horribly wrong, especially when odd quoting characters or pod is brought into the equation. eval is even worse. I'd advise anyone even thinking of trying to parse perl to look at what can be achieved, and then either improving that (to the benefit of everyone) or just to give up.

I do sometimes find myself chosing a particular way of coding over another (possibly better) way because the second breaks the pretty printing, and I want others using the same editor to be able to read the code I write.

I hate to say this, but even as an XEmacs fan, cperl+gemacs is far superior. Recent GNU Emacs has some extra stuff that XEmacs doesn't have, that allows cperl to do some really amazing things. (I have vague memories of the "extra stuff" being multiple syntax transition tables for each character, so you can gracefully handle things like m!!x and other non-standard delimiters. But I could be totally wrong.)

s/'"/;
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s/'"/;  #"'
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I just use backslashes for those. No need to "balance it".

-- Randal L. Schwartz, Perl hacker

@examples = split /\n/, <<'EXAMPLES';
sin / ...
time / ...
localtime / ...
caller / ...
eof / ...
use constant FOO => 35; FOO / ...
use Fcntl qw(LOCK_SH); LOCK_SH / ...
sub no_args (); sub no_args{1}; no_args / ...
sub one_arg ($); sub one_arg{1}; one_arg / ...
sub normal (@); sub normal{1}; normal / ...
EXAMPLES
for (@examples) {
    s=\.\.\.=25 ; # / ; die "this dies!";=;
    local($a) = eval;
    $a = $@ if $@;
    print "$_\n\t$a\n";
}
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everything seems parseable (is that the right word?) using some simple LL grammars.

No, only perl (the interpreter) can parse all of Perl (the language). See my node here for details.

Edit: added emphasis.

Static parsing is only reliable, if you rule out or control all imported subs, because prototypes change the way Perl is parsed. See HaukeX's other reply.

Basically changes at compile time ( see BEGIN blocks ) can change the parser.

Dynamic parsing is possible though, if you inspect the op-tree after compilation, that's the basic idea of some newer tools, like the perlnavigator.

See also perl -c in perlrun or B::Xref

Cheers Rolf
_{(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery}

Static parsing is only reliable, if you rule out or control all imported subs, because prototypes change the way Perl is parsed.

I think, though, that prototypes aren't the only reason Perl isn't statically parseable. There are quite a few heuristics that the parser uses that aren't all too well documented, and I'm not sure if a static parser would be able to reimplement all of them. And then there is no strict code, which I think gets even trickier. At some point I was considering researching and making a list of all of the reasons, but I unfortunately never got around to it.

That's why I said "the only thing that can parse Perl is perl"!

-- Randal L. Schwartz, Perl hacker

Stunning reading comprehension there. I wonder if such clueless folk ever come back and read their comments years later and feel a twinge of embarrassment.