Why GitHub use Haskell for their newly released Semantic package

The Semantic project is concerned with parsing, analyzing (evaluating), and comparing source code and as such we are firmly rooted in the academic domain of programming language theory (PLT) and spend significant time applying existing research to the real world problem of analyzing source code on GitHub. At this point, we are pretty firmly attached to Haskell’s language features to enable many of the objectives of this project: abstract interpretation, graph analysis, effect analysis, code writing, AST matching, etc. As it stands today, we’ve got 20k lines of Haskell code and some incredible program analysis capabilities at our disposal with little fear of adding more languages or supporting the changing needs of GitHub.

Source: github.com