futhark-0.25.19: An optimising compiler for a functional, array-oriented language.
Safe HaskellSafe-Inferred
LanguageGHC2021

Futhark.IR.Traversals

Description

Functions for generic traversals across Futhark syntax trees. The motivation for this module came from dissatisfaction with rewriting the same trivial tree recursions for every module. A possible alternative would be to use normal "Scrap your boilerplate"-techniques, but these are rejected for two reasons:

  • They are too slow.
  • More importantly, they do not tell you whether you have missed some cases.

Instead, this module defines various traversals of the Futhark syntax tree. The implementation is rather tedious, but the interface is easy to use.

A traversal of the Futhark syntax tree is expressed as a record of functions expressing the operations to be performed on the various types of nodes.

The Futhark.Transform.Rename module is a simple example of how to use this facility.

Synopsis

Mapping

data Mapper frep trep m Source #

Express a monad mapping operation on a syntax node. Each element of this structure expresses the operation to be performed on a given child.

Constructors

Mapper 

Fields

identityMapper :: forall rep m. Monad m => Mapper rep rep m Source #

A mapper that simply returns the tree verbatim.

mapExpM :: Monad m => Mapper frep trep m -> Exp frep -> m (Exp trep) Source #

Map a monadic action across the immediate children of an expression. Importantly, the mapping does not descend recursively into subexpressions. The mapping is done left-to-right.

mapExp :: Mapper frep trep Identity -> Exp frep -> Exp trep Source #

Like mapExpM, but in the Identity monad.

Walking

data Walker rep m Source #

Express a monad expression on a syntax node. Each element of this structure expresses the action to be performed on a given child.

Constructors

Walker 

Fields

identityWalker :: forall rep m. Monad m => Walker rep m Source #

A no-op traversal.

walkExpM :: Monad m => Walker rep m -> Exp rep -> m () Source #

As mapExpM, but do not construct a result AST.

Ops

class TraverseOpStms rep where Source #

This representation supports an OpStmsTraverser for its Op. This is used for some simplification rules.

Methods

traverseOpStms :: Monad m => OpStmsTraverser m (Op rep) rep Source #

Transform every sub-Stms of this op.

Instances

Instances details
TraverseOpStms Seq Source # 
Instance details

Defined in Futhark.IR.Seq

TraverseOpStms SeqMem Source # 
Instance details

Defined in Futhark.IR.SeqMem

TraverseOpStms (Wise GPU) Source # 
Instance details

Defined in Futhark.IR.GPU.Simplify

TraverseOpStms (Wise GPUMem) Source # 
Instance details

Defined in Futhark.IR.GPUMem

TraverseOpStms (Wise MC) Source # 
Instance details

Defined in Futhark.IR.MC

TraverseOpStms (Wise MCMem) Source # 
Instance details

Defined in Futhark.IR.MCMem

TraverseOpStms (Wise SOACS) Source # 
Instance details

Defined in Futhark.IR.SOACS.Simplify

TraverseOpStms (Wise Seq) Source # 
Instance details

Defined in Futhark.IR.Seq

TraverseOpStms (Wise SeqMem) Source # 
Instance details

Defined in Futhark.IR.SeqMem

type OpStmsTraverser m op rep = (Scope rep -> Stms rep -> m (Stms rep)) -> op -> m op Source #

A function for monadically traversing any sub-statements of the given op for some representation.

traverseLambdaStms :: Monad m => OpStmsTraverser m (Lambda rep) rep Source #

A helper for defining traverseOpStms.