W.r.t static analysis of perl, there would then seem to be a lot of things that would need to be sorted out (or at least heuristics provided for) to make it useful for the purposes of an IDE.

In fact, if someone is burdened¹ by the use of syntax highlighting when editting their Perl code, then their coding style will be somewhat skewed such that they avoid even reasonable constructs if they happen to confuse their syntax highlighter.

Heh :-) I do use syntax-highlighting wherever possible, if only because it allows me (in my perception) to skim my code faster.

I mostly use Vim (I've been trying to use Emacs of late)... it has lots of problems with its very simplistic highlighter. I don't avoid the "problematic" constructs; I've just formed a habit of inserting comments to "correct" those mistakes ;)

My impression is that PPI, in practice, is good enough often enough that a PPI-based IDE could be successful if used on a new project (due to the feedback loop I noted above). The effectiveness of a PPI-based IDE when applied to an existing code base is certainly less certain, IMHO.

Well, it has to start somewhere (assuming that making perl "more available" to beginners/infidels is a worthwhile goal).

I agree that the feedback loop would eventually lead to a parser that works reasonably for arbitrary perl5 code.

-David.