HListPP: A preprocessor for HList labelable labels

A preprocessor that replaces `longDescriptiveName with

hLens' (Label :: Label "longDescriptiveName")

Use with ghc flags -F -pgmF HListPP, which can be added per-file with a pragma:

❴-# OPTIONS_GHC -F -pgmF HListPP #-❵ -- change braces to ascii (haddock doesn't allow literal comments in files)

Note that `labels is expanded to something that takes up about 26 more columns. To avoid issues with layout, put a newline after keywords that introduce layout, at least if there are `labels in the same row. In other words:

`character.`position.`x %= \ x -> let
     msg = "a really long message about x>0"
     pos = x - 5
   in if pos < 0
         then error msg
         else pos

Instead of

`character.`position.`x %= \ x -> let msg = "a really long message about x>0"
                                      pos = x - 5
                           in if pos < 0
                               then error msg
                               else pos

A blank library is included in this package to make it possible to depend on HListPP

Downloads

• HListPP-0.2.1.tar.gz [browse] (Cabal source package)
• Package description (as included in the package)

Maintainer's Corner

Package maintainers

• AdamVogt

For package maintainers and hackage trustees

• edit package information

Candidates

• 0.2.2