I don't know any tool that does syntactical hilighting.
What they do is lexical hilighting when this is possible, that
is when tokenization is orthogonal with parsing.
A real tool will have to hook to the Perl parsing engine
to do a decent job in all cases. More generally I don't
know of any litterate development environment in the Open
Source world. We still use age old tool like emacs and vi
which is a sure sign how backward we are.
BTW:I am told that MS-Visual tool are far mode advanced.
This is very odd because litterate tools would fit more naturally
in Open Source world than in a closed one.
check out Nemo