Hackathon tasks - 3

[nponeccop]

• https://github.com/nponeccop/HNC/blob/master/HN/Optimizer/ExpressionRewriter.hs#L23 think if composeRewrites can be optimized
• https://github.com/nponeccop/HNC/blob/master/HN/Optimizer/Utils.hs#L31 See if anything can be done with repeated Nothing/Just patterns (common code or Monad/Alternative)
• https://github.com/nponeccop/HNC/blob/master/HN/Optimizer/Utils.hs#L52 See if fusing concatMap and foldr makes it simpler
• https://github.com/nponeccop/HNC/blob/master/HN/MilnerTools.hs#L53 Convert mrevert to recursion schemes
• https://github.com/nponeccop/HNC/blob/master/HN/MilnerTools.hs#L31 Use execStateT/evalStateT instead of runStateT to avoid fst
• https://github.com/nponeccop/HNC/blob/master/HN/MilnerTools.hs#L33 Use recursion schemes for convert. Note that you'll have to use sequenceM
• https://github.com/nponeccop/HNC/blob/master/HN/SplExport.hs#L31 Use zipWith to avoid two applications of map
• https://github.com/nponeccop/HNC/blob/master/HN/Visualise.hs#L16 Use LambdaCase (2 cases)
• Avoid letWhere. Directly pattern-match on letIn instead https://github.com/nponeccop/HNC/blob/master/HN/Visualise.hs#L12
• Eta-reduce (3 cases): https://github.com/nponeccop/HNC/blob/master/HN/Visualise.hs#L8
• Recursion schemes: https://github.com/nponeccop/HNC/blob/master/HN/Visualise.hs#L18