GHC.Tc.Errors.Hole.Plugin

Documentation

type CandPlugin = TypedHole -> [HoleFitCandidate] -> TcM [HoleFitCandidate]

A plugin for modifying the candidate hole fits *before* they're checked.

type FitPlugin = TypedHole -> [HoleFit] -> TcM [HoleFit]

A plugin for modifying hole fits *after* they've been found.

data HoleFitPlugin

A HoleFitPlugin is a pair of candidate and fit plugins.

Constructors

HoleFitPlugin

Fields

• candPlugin :: CandPlugin
• fitPlugin :: FitPlugin

data HoleFitPluginR

HoleFitPluginR adds a TcRef to hole fit plugins so that plugins can track internal state. Note the existential quantification, ensuring that the state cannot be modified from outside the plugin.

Constructors

forall s. HoleFitPluginR

Fields

• hfPluginInit :: TcM (TcRef s)

  Initializes the TcRef to be passed to the plugin

• hfPluginRun :: TcRef s -> HoleFitPlugin

  The function defining the plugin itself

• hfPluginStop :: TcRef s -> TcM ()

  Cleanup of state, guaranteed to be called even on error