spec/collection/accumulate_spec.cr

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• Last update: 2022-03-25 20:11:13+09:00

Depends on

• src/collection/accumulate.cr

Code

require "spec"
require "../../src/collection/accumulate"

describe Enumerable do
  it "#accumulate(init)" do
    [0, 1, 2, 3].accumulate(3).should eq [3, 3, 4, 6, 9]
    (0..3).accumulate(3).should eq [3, 3, 4, 6, 9]
  end

  it "#accumulate(init, &block)" do
    [1, 2, 3, 4].accumulate(1) { |x, y| x * y }.should eq [1, 1, 2, 6, 24]
    (1..4).accumulate(1) { |x, y| x * y }.should eq [1, 1, 2, 6, 24]
    [3, 1, 4, 1, 5].accumulate(0) { |x, y| Math.max(x, y) }.should eq [0, 3, 3, 4, 4, 5]
  end

  it "#accumulate" do
    [0, 1, 2, 3].accumulate.should eq [0, 1, 3, 6]
    (0..3).accumulate.should eq [0, 1, 3, 6]
  end
end

require "spec"

# require "../../src/collection/accumulate"
module Enumerable(T)
  def accumulate(init : U) : Array(U) forall U
    accumulate(init) { |a, b| a + b }
  end

  def accumulate : Array(T)
    accumulate { |x, y| x + y }
  end

  def accumulate(init : U, &block : U, T -> U) : Array(U) forall U
    result = [init]
    each { |v| result << yield(result.last, v) }
    result
  end

  def accumulate(&block : T, T -> T) : Array(T)
    result = [] of T
    memo = uninitialized T
    each do |v|
      memo = result.empty? ? v : yield(memo, v)
      result << memo
    end
    result
  end
end

describe Enumerable do
  it "#accumulate(init)" do
    [0, 1, 2, 3].accumulate(3).should eq [3, 3, 4, 6, 9]
    (0..3).accumulate(3).should eq [3, 3, 4, 6, 9]
  end

  it "#accumulate(init, &block)" do
    [1, 2, 3, 4].accumulate(1) { |x, y| x * y }.should eq [1, 1, 2, 6, 24]
    (1..4).accumulate(1) { |x, y| x * y }.should eq [1, 1, 2, 6, 24]
    [3, 1, 4, 1, 5].accumulate(0) { |x, y| Math.max(x, y) }.should eq [0, 3, 3, 4, 4, 5]
  end

  it "#accumulate" do
    [0, 1, 2, 3].accumulate.should eq [0, 1, 3, 6]
    (0..3).accumulate.should eq [0, 1, 3, 6]
  end
end

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