Cabal type provider extension

[ocramz]

Proposal for .cabal extension

Instead of building normal executable, we would mark it type-provider:

type-provider ExcelTypeProvider.hs
  mime-types: text/plain
  glob: *.xlsx

It can either have a list of glob patterns for matching file and directory names, or have mime-types for matching MIME type (warning: MIME type matching may work differently on different operating systems!).

[ocramz]

This one is such a cool idea I had to investigate; Cabal pre-processors seem to be a good starting point: https://www.haskell.org/cabal/release/cabal-latest/doc/API/Cabal/Distribution-Simple-PreProcess.html#t:PreProcessor .