| Copyright | Copyright (C) 2004-2011 John Goerzen |
|---|---|
| License | BSD3 |
| Maintainer | John Goerzen <jgoerzen@complete.org> |
| Stability | provisional |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell98 |
Data.Map.Utils
Contents
Description
This module provides various helpful utilities for dealing with Data.Maps.
Written by John Goerzen, jgoerzen@complete.org
- flipM :: (Ord key, Ord val) => Map key val -> Map val [key]
- flippedLookupM :: (Ord val, Ord key) => val -> Map key val -> [key]
- forceLookupM :: (Show key, Ord key) => String -> key -> Map key elt -> elt
- strToM :: (Read a, Read b, Ord a) => String -> Map a b
- strFromM :: (Show a, Show b, Ord a) => Map a b -> String
Basic Utilities
flipM :: (Ord key, Ord val) => Map key val -> Map val [key] Source
Flips a Map. See flipAL for more on the similar
function for lists.
flippedLookupM :: (Ord val, Ord key) => val -> Map key val -> [key] Source
Returns a list of all keys in the Map whose value matches the parameter. If the value does not occur in the Map, the empty list is returned.
forceLookupM :: (Show key, Ord key) => String -> key -> Map key elt -> elt Source
Performs a lookup, and raises an exception (with an error message prepended with the given string) if the key could not be found.
Conversions
strToM :: (Read a, Read b, Ord a) => String -> Map a b Source
Converts a String into a String, String Map. See
strToAL for more on the similar function for association
lists.
This implementation is simple:
strToM = Data.Map.fromList . strToAL
This function is designed to work with Map String String objects, but may work with other key/value combinations if they have simple representations.
strFromM :: (Show a, Show b, Ord a) => Map a b -> String Source
Converts a String, String Map into a string representation.
See strFromAL for more on the similar function for
association lists. This implementation is simple:
strFromM = strFromAL . Data.Map.toList
This function is designed to work with Map String String objects, but may also work with other objects with simple representations.