Trigram kata for 10/10/2013

story_creator_spec.rb

require 'rspec-given'

class StoryCreator
  def initialize(story, selector_fn = nil)
    @story = story
    @selector_fn = selector_fn
  end

  def new_story
    trigram = {
      "I wish" => ["I"],
      "wish I" => ["may"]
    }

    if ! @selector_fn
      @story
    else
      start_point = @selector_fn.call(trigram)
      "#{start_point} #{trigram[start_point].first}"
    end
  end
end

describe StoryCreator do
  context "with 1 word" do
    Given(:story_creator) { StoryCreator.new("I") }
    Then                  { story_creator.new_story == "I" }
  end

  context "with 2 words" do
    Given(:story_creator) { StoryCreator.new("I wish") }
    Then                  { story_creator.new_story == "I wish" }
  end

  context "with words" do
    Given(:story_creator) { StoryCreator.new("I wish I may", ->(trigram) { "wish I" } ) }
    Then                  { story_creator.new_story == "wish I may" }
  end
end


{
  "I wish" => ["I"],
  "wish I" => ["may"]
}