This is true. I'm currently working on a research compiler targeting GPUs. It's 7500 lines of Haskell with all comments and blank lines removed, and the only

This is true. I'm currently working on a research compiler targeting GPUs. It's 7500 lines of Haskell with all comments and blank lines removed, and the only impure part is the command line interface. Avoiding IO is not really painful for these kinds of programs.