EdisonAPI-1.3.1: A library of efficient, purely-functional data structures (API)

Copyright Copyright (c) 1998 Chris Okasaki BSD3; see COPYRIGHT file for terms and conditions robdockins AT fastmail DOT fm stable GHC, Hugs (MPTC and FD) Safe Haskell2010

Data.Edison.Prelude

Contents

Description

This module is a central depository of common definitions used throughout Edison.

Synopsis

# Hashing classes

class Eq a => Hash a where Source #

This class represents hashable objects. If obeys the following invariant:

forall x,y :: a. (x == y) implies (hash x == hash y)

Minimal complete definition

hash

Methods

hash :: a -> Int Source #

class Hash a => UniqueHash a Source #

This class represents hashable objects where the hash function is unique (injective). There are no new methods, just a stronger invariant:

forall x,y :: a. (x == y) iff (hash x == hash y)

class UniqueHash a => ReversibleHash a where Source #

This class represents hashable objects where the hash is reversible.

forall x :: a. unhash (hash x) == x

Note that:

hash (unhash i) == i

does not necessarily hold because unhash is not necessarily defined for all i, only for all i in the range of hash.

Minimal complete definition

unhash

Methods

unhash :: Int -> a Source #

class Monoid v => Measured v a | a -> v where Source #

This class represents a quantity that can be measured. It is calculated by an associative function with a unit (hence the Monoid superclass, and by a function which gives the measurement for an individual item. Some datastructures are able to speed up the calculation of a measure by caching intermediate values of the computation.

Minimal complete definition

measure

Methods

measure :: a -> v Source #