module Enumerable

Constants

SINGLE_SIZE

Public Instance Methods

find_mset(value, multiplicity=-1) click to toggle source

@note Uses HF::Range Returns the range of the first one-member multiset collecting the specified value at the given multiplicity. This is a collection such as [3, 3, 3 ,3], where there is multiple instances of one member. Formally it is a multiset with only one member. The default multiplicity returns the range of an mset of arbirtrary size. The default value is not specified it returns the range of the first mset with distinct values. @param value [Object] the element in the mset @param multiplicity [Integer] the number of times value appears in mset @return [Range] the first range where the subset occurs

# File lib/hf.rb, line 37
def find_mset(value, multiplicity=-1)
  is_multiplicity_negative = multiplicity < 0
  enums_chunked_on_value = self.chunk{|i| i == value}
  sub_enums = enums_chunked_on_value.collect{|r| r.last}
  sub_enums_is_mset =
    if is_multiplicity_negative
      enums_chunked_on_value.collect{|r| r.first && not(r.single?) }
    else
      enums_chunked_on_value.collect{|r| r.first && (r.last.size >= multiplicity) }
    end
  first_mset_chunked_index = sub_enums_is_mset.find_index(true)
  return Range.new(self.count, self.count, true) if first_mset_chunked_index.nil?
  first_mset_offset = sub_enums.take(first_mset_chunked_index).flatten.size
  first_mset_size = is_multiplicity_negative ? sub_enums[first_mset_chunked_index].size : multiplicity
  Range.new(0, first_mset_size.pred).bump(first_mset_offset)
end

only() click to toggle source

Returns the only element in a 1-tuple/single. A more idiomatic and safer accessor than first when the Enumerator is expected to have only one element. @raise [WrongSize] when the enumerator is not a 1-tuple @return [Object] the element in the 1-tuple enumerator

# File lib/hf.rb, line 22
def only
  return self.first if self.single?
  raise WrongSize, wrong_size_message(self.count, SINGLE_SIZE)
end

single?() click to toggle source

@return [Boolean] true when enum is a 1-tuple or single

# File lib/hf.rb, line 12
def single?
  return true if self.count == SINGLE_SIZE
  return false
end

Private Instance Methods

wrong_size_message(expected_size, actual_size) click to toggle source

@param expected_size [Integer] @param actual_size [Integer] @return [String] the message for the WrongSize exception

# File lib/hf.rb, line 59
def wrong_size_message(expected_size, actual_size)
  elm_word = actual_size == 1 ? "element" : "elements"
  "Enumerator is not a #{expected_size}-tuple. It has #{actual_size} #{elm_word} instead of #{expected_size}"
end