derive-0.1.1: A program and library to derive instances for data types Source code Contents Index

Data.DeriveTraversal

Description

Derives Functor and similair classes, as discussed on the Haskell-prime mailing list: http://www.mail-archive.com/haskell-prime@haskell.org/msg02116.html.

Synopsis

data TraveralType = TraveralType { traversalArg :: Int traversalCo :: Bool traversalName :: String traversalId :: Trav traversalDirect :: Trav traversalFunc :: String -> Trav -> Trav traversalPlus :: Trav -> Trav -> Trav traverseArrow :: Trav -> Trav -> Trav traverseTuple :: [Exp] -> Exp traverseCtor :: String -> [Exp] -> Exp traverseFunc :: Pat -> Exp -> Clause } defaultTraversalType traversalInstance :: TraveralType -> String -> DataDef -> [WithInstances Dec] -> [Dec] traversalInstance1 :: TraveralType -> String -> DataDef -> [Dec] deriveTraversal :: TraveralType -> DataDef -> WithInstances Dec

Documentation

data TraveralType Source

What kind of traversal are we deriving? Constructors TraveralType traversalArg :: Int On what position are we traversing? traversalCo :: Bool covariant? traversalName :: String name of the traversal function traversalId :: Trav Identity traversal traversalDirect :: Trav Traversal of a traversalFunc :: String -> Trav -> Trav Apply the sub-traversal function traversalPlus :: Trav -> Trav -> Trav Apply two non-identity traversals in sequence traverseArrow :: Trav -> Trav -> Trav Traverse a function type traverseTuple :: [Exp] -> Exp Construct a tuple from applied traversals traverseCtor :: String -> [Exp] -> Exp Construct a data type from applied traversals traverseFunc :: Pat -> Exp -> Clause Construct a clause of the traversal function

defaultTraversalType

traversalInstance :: TraveralType -> String -> DataDef -> [WithInstances Dec] -> [Dec] Source

Instance for a Traversable like class

traversalInstance1 :: TraveralType -> String -> DataDef -> [Dec] Source

Instance for a Traversable like class with just 1 method

deriveTraversal :: TraveralType -> DataDef -> WithInstances Dec Source

Derive a traverse like function

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