Language.Haskell.TH.Lens

Lenses and Traversals for working with Template Haskell

Documentation

class HasName t where

Has a Name

Methods

name :: Simple Lens t Name

Extract (or modify) the Name of something

Instances

HasName Name

HasName TyVarBndr

HasName Con

class HasTypeVars t where

Provides for the extraction of free type variables, and alpha renaming.

Methods

typeVarsEx :: Set Name -> Simple Traversal t Name

When performing substitution into this traversal you're not allowed to substitute in a name that is bound internally or you'll violate the Traversal laws, when in doubt generate your names with newName.

Instances

HasTypeVars Type

HasTypeVars Name

HasTypeVars Pred

HasTypeVars TyVarBndr

HasTypeVars t => HasTypeVars [t]

class SubstType t where

Provides substitution for types

Methods

substType :: Map Name Type -> t -> t

Perform substitution for types

Instances

SubstType Type

SubstType Pred

SubstType t => SubstType [t]

typeVars :: HasTypeVars t => Simple Traversal t Name

Traverse free type variables

substTypeVars :: HasTypeVars t => Map Name Name -> t -> t

Substitute using a map of names in for free type variables

conFields :: Simple Traversal Con StrictType

Provides a Traversal of the types of each field of a constructor.

conNamedFields :: Simple Traversal Con VarStrictType

Traversal of the types of the named fields of a constructor.