[joe_the_user]

Ease of building it yourself compared to learning someone else's system is a major reason Lisp is languishing, in my opinion.

Oh, that why Perl is languishing too. Well, the problem is how hard it is to learn someone else's system in Perl. If Lisp has that problem, well, there you are.

[randallsquared]

I don't think Lisp has that problem. Rather, it has the "problem" that it's easier to build the 20% you need of that library than to find the library, understand enough to do the bit you need in the face of that inevitable impedance mismatch between your abstractions and the library author's, figure out how including it impacts the rest of your system including the dependencies...

In other languages, this is just something everyone has to live with, and because of that, libraries face strong selection pressure to be one or more of simple, fast, standard, etc. There is no particular pressure like that in Lisp, since there's a much smaller domain where it's easy to understand why you need a thing, and troublesome to build it. To a much greater degree than mainstream languages, then, there are almost as many "language + standard library" sets as there are Lisp developers. You can see this same effect at work in Python web frameworks, I think.

[gnosis]

Perl is definitely not languishing. It just gets a bad rap from fans of other languages that are competing with it (particularly from the fans of Python and Ruby, the two upstarts trying to take its place).

Let's look at the number of jobs advertised for Perl, Python, Ruby, and Lisp over the last 5 years:

http://www.indeed.com/jobtrends?q=perl%2Cpython%2Cruby%2Clis...

The number of Perl jobs is more than those of Python and Ruby put together. Lisp has so few jobs it doesn't even really show up on the chart.

Then there's Perl's CPAN archive, with over 17,000 modules, with about 30 modules updated or added per day. That much development is a sign of an active, alive community.

So the rumors of Perl's demise are greatly exaggerated.