I criticized Allegro yesterday at Between the Lines for a business model that sells programming language development environments like they were enterprise software. Programming languages and their development environments are free in the 21st century--at least that's how most people think about them. I can't imagine approaching a VC, for example, with a business plan that has as it's basis selling programming language tools.

The problem is that programming languages depend on complex ecosystems of libraries, IDEs, testing tools, Web components, and so on. A reader at BTL said it in this way:

Where's the ecosystem?

LISP was born in 1958... but where's the ecosystem of tools and libraries--FOSS and commercial--that surrounds C++, Java Perl, Python, PHP and even the .NET platform? Ruby dovumentation and libraries are so much easier to come by and that language was born in the mid-90s.

Looks like LISP's fans have a lot of work to do if they want to bridge the support gap with competing languages and platforms. Until that happens, LISP will be like Latin--historically significant but otherwise dead.

There actually is a community of people who use LISP, but it's not as big as it could be. Several factors contribute to this:

Common Lisp isn't all that common. That is, the CL spec covers the language, but not much else. Transferring programs is hard. This contrasts sharply with new languages like PHP, Python, and Ruby where the core language and libraries are free so there's only one implementation. Consequently, developers create large bodies of code that can be easily used by anyone else.