i did a quick check about what source-code-management systems are used by the programming languages that i find important/interesting, and here is what i found:
| python | subversion |
| ruby | subversion |
| gcc | subversion |
| sbcl (lisp) | cvs |
| factor | git |
| ghc (haskell) | darcs |
| openjdk (java) | mercurial |
| lua | no public repo |