README.md

nimonoid

A monoid library for Nim.

A monoid is a type with an operation to combine 2 values and a neutral element for this operation.

Backend compatibility

• C
• C++
• Objective-C
• JavaScript
• NimScript (not tested yet)

Installation

nimble install 'https://github.com/thenjip/nimonoid'

Dependencies

• nim >= 1.6.4 & < 2.0.0
• funcynim >= 1.0.0 & < 2.0.0

Documentation

• API

Features

API to check the monoid laws for an implementation

• somemonoid.nim

  type SomeMonoid = string
  
  proc neutral*(X: typedesc[SomeMonoid]): X =
    ""
  
  proc fold*(left, right: SomeMonoid): SomeMonoid =
    left & right

• test.nim

  import somemonoid
  import pkg/nimonoid/[laws]
  import pkg/funcynim/[curry, run]
  import std/[unittest]
  
  suite "somemonoid":
    test "SomeMonoid should verify the monoid laws.":
      proc doTest(spec: AllLawsSpec[SomeMonoid]) =
        let (leftIdentity, rightIdentity, associativity) = spec.verify()
  
        check(leftIdentity.isVerified())
        check(rightIdentity.isVerified())
        check(associativity.isVerified())
  
      allLawsSpec(leftIdentitySpec("abc"))
        .with(rightIdentitySpec("0213 "))
        .run(associativitySpec("jUFha")("pdAbhqc")("5JK0jkty"))
        .doTest()

Monoid implementations for standard types

• Integers
  • Addition
  • Multiplication
• Linear data structures
  • Concatenation
• And more.