class Spruz::Generator

This class can create generator objects, that can produce all tuples, that would be created by as many for-loops as dimensions were given.

The generator

g = Spruz::Generator[1..2, %w[a b c]]

produces

g.to_a # => [[1, "a"], [1, "b"], [1, "c"], [2, "a"], [2, "b"], [2, "c"]]

The 'each' method can be used to iterate over the tuples

g.each { |a, b| puts "#{a} #{b}" }

and Spruz::Generator includes the Enumerable module, so Enumerable.instance_methods can be used as well:

g.select { |a, b| %w[a c].include? b  } # => [[1, "a"], [1, "c"], [2, "a"], [2, "c"]]

Public Class Methods

[](*enums) click to toggle source

Create a new Generator object from the enumberables enums.

# File lib/spruz/generator.rb, line 20
def self.[](*enums)
  new(enums)
end
new(enums) click to toggle source

Create a new Generator instance. Use the objects in the Array enums as dimensions. The should all respond to the :each method (see module Enumerable in the core ruby library).

# File lib/spruz/generator.rb, line 27
def initialize(enums)
  @enums, @iterators, @n = [], [], 0
  enums.each { |e| add_dimension(e) }
end

Public Instance Methods

add_dimension(enum, iterator = :each) click to toggle source

Add another dimension to this generator. enum is an object, that ought to respond to the iterator method (defaults to :each).

# File lib/spruz/generator.rb, line 55
def add_dimension(enum, iterator = :each)
  @enums << enum
  @iterators << iterator
  @n += 1
end
each() { |tuple| ... } click to toggle source

Iterate over all tuples produced by this generator and yield to them.

# File lib/spruz/generator.rb, line 33
def each(&block) # :yield: tuple
  recurse(&block)
  self
end
size() click to toggle source

Return the size of this generator, that is the number of its dimensions.

# File lib/spruz/generator.rb, line 62
def size
  @enums.size
end

Private Instance Methods

recurse(tuple = [ nil ] * @n, i = 0) { |dup| ... } click to toggle source
# File lib/spruz/generator.rb, line 38
def recurse(tuple = [ nil ] * @n, i = 0, &block)
  if i < @n - 1 then
    @enums[i].__send__(@iterators[i]) do |x|
      tuple[i] = x
      recurse(tuple, i + 1, &block)
    end
  else
    @enums[i].__send__(@iterators[i]) do |x|
      tuple[i] = x
      yield tuple.dup
    end
  end
end