Map -package:containers

A Map from keys k to values a. The Semigroup operation for Map is union, which prefers values from the left operand. If m1 maps a key k to a value a1, and m2 maps the same key to a different value a2, then their union m1 <> m2 maps k to a1.

Invariant preserving version of Map from the containers packages, suitable for use with Uniplate. Use toMap to construct values, and fromMap to deconstruct values.

Contains implementation of polymorphic type classes for data types Set and Map.

Strict Map. Import as:

import qualified RIO.Map as Map

This module does not export any partial or unchecked functions. For those, see RIO.Map.Partial and RIO.Map.Unchecked

Instances to convert between Map and association list. Copyright (C) 2009-2011 John Goerzen jgoerzen@complete.org All rights reserved. For license and copyright information, see the file LICENSE

Map type used to represent records and unions

A Map that remembers the original ordering of keys This is primarily used so that formatting preserves field order This is done primarily to avoid a dependency on insert-ordered-containers and also to improve performance

Hash-table, based on STM-specialized Hash Array Mapped Trie.

A Map from keys k to values a. The Semigroup operation for Map is union, which prefers values from the left operand. If m1 maps a key k to a value a1, and m2 maps the same key to a different value a2, then their union m1 <> m2 maps k to a1.

Type-level fmap for type-level functors. Note: this name clashes with Map from containers. FMap is provided as a synonym to avoid this.

Example

>>> data Example where Ex :: a -> Example  -- Hide the type of examples to avoid brittleness in different GHC versions

>>> data AddMul :: Nat -> Nat -> Exp Nat

>>> type instance Eval (AddMul x y) = (x TL.+ y) TL.* (x TL.+ y)

>>> :kind! Ex (Eval (Map (AddMul 2) '[0, 1, 2, 3, 4]) :: [Nat])
Ex (Eval (Map (AddMul 2) '[0, 1, 2, 3, 4]) :: [Nat]) :: Example
= Ex [4, 9, 16, 25, 36]

A Map from keys k to values a.

Map a type level function over a Row.

TOML-specific combinators for converting between TOML and Haskell Map-like data types. There are two way to represent map-like structures with the tomland library.

• Map structure with the key and value represented as key-value pairs:

  foo = [ {myKey = "name", myVal = 42} , {myKey =
  "otherName", myVal = 100} ] 

• Map structure as a table with the TOML key as the map key:

  [foo] name = 42 otherName = 100 

You can find both types of the codecs in this module for different map-like structures. See the following table for the heads up: TODO: table Note: in case of the missing key on the TOML side an empty map structure is returned.

This module defines finite maps where the key and value types are parameterized by an arbitrary kind. Some code was adapted from containers.

Lists of pairs representing maps. The Listable tiers enumeration will not have repeated maps.

> take 6 (list :: [Map Nat Nat])
[Map [],Map [(0,0)],Map [(0,1)],Map [(1,0)],Map [(0,2)],Map [(1,1)]]