Module: MadderLib::Conditional::Likely::Instruction

Included in:
Instruction
Defined in:
lib/madderlib/conditional/likely.rb

Overview

Likely::Instruction

Introduces support for proportional selection from multiple Instructions in a given Phrase

See: Likely::Phrase

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(target) ⇒ Object

:nodoc:



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# File 'lib/madderlib/conditional/likely.rb', line 83

def self.included(target) #:nodoc:
  #  register a test to test all allowances for the instruction
  #    return false at the first one that fails
  target.add_test do |instruction, context|
    phrase = instruction.phrase
    test = true

    state = context.state(phrase)
    total = state[:likely_total]
    count = state[:likely_count]

    # will only have a count if there's likelihood calc required
    if count
      state = context.state(instruction)
      lower = state[:likely_lower]
      upper = state[:likely_upper]

      test = (count >= lower) && (count < upper)

      if test && phrase.respond_to?(:recurs?) && phrase.recurs?
        # set it up for the next recurrance
        #   we don't want the same thing over and over again
        state[:likely_count] = rand(total)
      end
    end

    test
  end
end

Instance Method Details

#conditional_likely_tester ⇒ Object

:nodoc:



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# File 'lib/madderlib/conditional/likely.rb', line 155

def conditional_likely_tester #:nodoc:
  @likely_tester
end

#likely(*args, &block) ⇒ Object Also known as: weight, weighted, weighing, odds

Specifies the likelihood of this Instruction being used, compared to its siblings in their Phrase

If provided, the arguments should contain:

  • a numeric value, which becomes the weight

  • a Range, or two numerics (which define a Range), from which the weight is chosen randomly

  • a Proc / lambda / block / closure, which returns a numeric value. \

The block can either take no arguments, or a Context.

See: Instruction#alternately

Examples:

builder = madderlib do
  say('parsley').likely(4)
  alternately(3).say('sage')
  alternately.say('rosemary').weighted(2).or.say('thyme')
end

usage = {}
60.times do
  key = builder.sentence
  usage[key] = (usage[key] || 0) + 1
end

#  if proportions were accurately reproducible:
#    usage['parsley'].should eql(20)
#    usage['sage'].should eql(15)
#    usage['rosemary'].should eql(10)
#    usage['thyme'].should eql(5)



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# File 'lib/madderlib/conditional/likely.rb', line 143

def likely(*args, &block)
  #  build a tester, set it aside
  @likely_tester = Helper::TestBlock.new *args, &block
  self
end