Improve files generated by bnfc

[deemp]

• Par.y:

  • Support start and end positions
    • Like in the blog
    • OR, use a patched bnfc
  • Improve error messages using position information

• Abs.hs

  • Include custom code (see happy docs)
    • instance Plated Object (see Plated) (related to Rewrite rules using lens #18)
  • Use Text instead of String
  • (?) Use Bytes Integer

• Print.hs

  • Pretty-print Bytes

[aabounegm]

About the Text instead of String point, there is an undocumented BNFC flag that would help: --text-token