I was thinking more stream fusion and rewrite rules etc. GHC is a lot more powerful in that sense than the other language compilers I mentioned. A lot of it in

I was thinking more stream fusion and rewrite rules etc. GHC is a lot more powerful in that sense than the other language compilers I mentioned. A lot of it in Haskell just boils down to bang patterns on data types. And where it does get messy as you suggest (yeah it does), you can nicely abstract it away behind a pure library interface. That way the mess is encapsulated.