avnik/text-literal-plugin

GHC plugin for wrapping all string literals with Text type annotation

Motivation

    class AsText a where
      asText :: a -> Bool

    instance AsText String where
      asText _ = False

    instance AsText T.Text where
      asText _ = True

    bar = asText "foo"

Fail as ambiguous string literal found, compiler can't decide instance here.

We wanted overloaded strings to be a Text by default, so plugin add type annotation

    bar = asText ("foo" :: Data.Text.Text)

qualified import on Data.Text also would be auto added:

    import qualified Data.Text

GHC versions support

Tested with GHC 8.8.4

Code written with other GHC versions in mind, but no tests was performed.

Copyrights

Development backed by Monadfix OU, and Juspay Technologies Pvt Ltd Shim.hs was borrowed from large-records, and copyrighted by Edsko de Vries and Well Typed.