Class: DarrylJenks::Permutable

Inherits:
Object
  • Object
show all
Defined in:
lib/darryl_jenks/permutable.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(key_string = nil) ⇒ Permutable

Constructor can be initialized with the key_string to initialize off of



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# File 'lib/darryl_jenks/permutable.rb', line 8

def initialize( key_string = nil )
  self.key_string = key_string
end

Instance Attribute Details

#key_string ⇒ Object

Returns the value of attribute key_string.



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# File 'lib/darryl_jenks/permutable.rb', line 3

def key_string
  @key_string
end

Instance Method Details

#each_permutation(permutable_key, substitution_value, options = {}) ⇒ Object

Computes the Permutations of a string

Ex: key_string = “HELLO WORLD FIRST”

each_permutation(“ ”, “-”) dash_permutations = [ “HELLO-WORLD FIRST”, “HELLO-WORLD-FIRST”, “HELLO WORLD-FIRST” ]

The ‘permutable_key’ is the character/regex that should be used as the split mechanism to determine how many objects are in the collection to be “permed”

The ‘substitution_value’ is the character that should be used in the permutations of the string as the separator value



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# File 'lib/darryl_jenks/permutable.rb', line 26

def each_permutation(permutable_key, substitution_value, options = {})
  return unless self.key_string.index(permutable_key)
  
  permutations = []
  split_tokens = self.key_string.split(permutable_key,-1)
  # At least a single permutation needs to be present
  number_of_permutations = [(split_tokens.size - 1), 1].max

  permutations_for(number_of_permutations).each do |permutation_pattern|
    permutation_string = ""
    copied_tokens = split_tokens.map(&:dup)

    permutation_pattern.each do |replace_split_token|
      permutation_string << copied_tokens.shift

      if replace_split_token
        permutation_string << substitution_value
      else
        permutation_string << (options[:non_replace_substitution] || permutable_key)
      end
    end

    permutation_string << copied_tokens.shift unless copied_tokens.empty?
    permutations << permutation_string
  end

  if block_given?
    permutations.each do |permutation|
      yield permutation
    end
  else
    permutations.to_enum
  end
end