| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
FreeC.IR.Unification
Contents
Description
This module contains functions for calculating the most general unificator (mgu) of two type expressions.
Synopsis
- data UnificationError
- reportUnificationError :: MonadReporter m => SrcSpan -> UnificationError -> m a
- unifyOrFail :: SrcSpan -> Type -> Type -> Converter (Subst Type)
- unifyAllOrFail :: SrcSpan -> [Type] -> Converter (Subst Type)
- unify :: Type -> Type -> ExceptT UnificationError Converter (Subst Type)
- unifyAll :: [Type] -> ExceptT UnificationError Converter (Subst Type)
Error Reporting
data UnificationError Source #
An error that can occur during the unification of two types.
reportUnificationError :: MonadReporter m => SrcSpan -> UnificationError -> m a Source #
Reports the given UnificationError.
unifyOrFail :: SrcSpan -> Type -> Type -> Converter (Subst Type) Source #
Like unify but reports a fatal error message if the types cannot be
unified.
The error message uses the given location information.
unifyAllOrFail :: SrcSpan -> [Type] -> Converter (Subst Type) Source #
Like unifyAll but reports a fatal error message if the types cannot be
unified.
The error message uses the given location information.
Unification
unify :: Type -> Type -> ExceptT UnificationError Converter (Subst Type) Source #
Calculates the mgu of the given type expressions.
The algorithm will preferably map the internal variable names to non-internal variables. This ensures that the names specified by the user are preserved. Otherwise variables in the first argument preferably mapped to variables in the second argument.
Type synonyms are expanded only when necessary.