| Safe Haskell | None |
|---|---|
| Language | Haskell98 |
Language.Haskell.TH.ExpandSyns
Contents
- expandSyns :: Type -> Q Type
- expandSynsWith :: SynonymExpansionSettings -> Type -> Q Type
- data SynonymExpansionSettings
- noWarnTypeFamilies :: SynonymExpansionSettings
- substInType :: (Name, Type) -> Type -> Type
- substInCon :: (Name, Type) -> Con -> Con
- evades :: Data t => [Name] -> t -> [Name]
- evade :: Data d => Name -> d -> Name
Expand synonyms
expandSyns :: Type -> Q Type Source #
Calls expandSynsWith with the default settings.
expandSynsWith :: SynonymExpansionSettings -> Type -> Q Type Source #
Expands all type synonyms in the given type. Type families currently won't be expanded (but will be passed through).
noWarnTypeFamilies :: SynonymExpansionSettings Source #
Suppresses the warning that type families are unsupported.
Misc utilities
evades :: Data t => [Name] -> t -> [Name] Source #
Make a list of names (based on the first arg) such that every name in the result is distinct from every name in the second arg, and from the other results
evade :: Data d => Name -> d -> Name Source #
Make a name (based on the first arg) that's distinct from every name in the second arg
Example why this is necessary:
type E x = forall y. Either x y ... expandSyns [t| forall y. y -> E y |]
The example as given may actually work correctly without any special capture-avoidance depending
on how GHC handles the ys, but in any case, the input type to expandSyns may be an explicit
AST using mkName to ensure a collision.