<< As far as performance goes, once you commit to a language with no mutable types, you have no recourse once you discover a bottleneck due to immutability. Tha

<< As far as performance goes, once you commit to a language with no mutable types, you have no recourse once you discover a bottleneck due to immutability. That's a big worry. All of the FP languages I'm familiar with provide easy access to mutable collections.