Portability	not at all
Stability	experimental
Maintainer	Joachim Breitner <[email protected]>
Safe Haskell	None

GHC.Dup

Description

This module provides two new operations, dup and deepDup, that allow you to prevent the result of two evaluations of the same expression to be shared.

Synopsis

Documentation

data Box a Source

The Box datatype allows you to control the time of evaluations of dup or deepDup, by pattern-matching on the result.

Constructors

Box a

dup :: a -> Box aSource

Dup copies a the parameter and returns it. The copy is shallow, i.e. referenced thunks are still shared between the parameter and its copy.

deepDup :: a -> Box aSource

This copies the parameter and changes all references therein so that when they are evaluated, they are copied again. This ensures that everything put on the heap by a function that wraps all is parameters in deepDup can be freed after the evaluation.