Class: MTK::Patterns::Palindrome

Inherits:
Cycle show all
Defined in:
lib/mtk/patterns/palindrome.rb

Overview

An endless enumerator that outputs an element one at a time from a list of elements, looping back to the beginning when elements run out.

Instance Attribute Summary

Attributes inherited from Pattern

#cycle_count, #element_count, #elements, #max_cycles, #max_elements, #min_elements, #options

Instance Method Summary collapse

Methods inherited from Cycle

#initialize

Methods inherited from Pattern

#empty?, from_a, #initialize, #max_cycles_exceeded?, #max_elements_exceeded?, #min_elements_unmet?, #next, #rewind

Methods included from Groups::Collection

#==, #[], #clone, #concat, #each, #empty?, #enumerable_map, #first, #last, #map, #partition, #permute, #repeat, #reverse, #rotate, #size, #to_a

Constructor Details

This class inherits a constructor from MTK::Patterns::Cycle

Instance Method Details

#advance ⇒ Object (protected)

Update internal state (index, etc) and set @current to the next element.

Raises:

  • (StopIteration) 


23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
 
# File 'lib/mtk/patterns/palindrome.rb', line 23

def advance
  raise StopIteration if @elements.nil? or @elements.empty? # prevent infinite loops

  @index += @direction

  if @index >= @elements.length
    @direction = -1
    @index = @elements.length - 1
    @index -= 1 unless repeat_ends? or @elements.length == 1

  elsif @index < 0
    @direction = 1
    @index = 0
    @index += 1 unless repeat_ends? or @elements.length == 1
  end

  @current = @elements[@index]
end

#repeat_ends? ⇒ Boolean

true if the first/last element are repeated when the ends are reached, else false

Returns:

  • (Boolean) 


9
10
11
 
# File 'lib/mtk/patterns/palindrome.rb', line 9

def repeat_ends?
  @repeat_ends ||= @options.fetch :repeat_ends, false
end

#rewind_or_cycle(is_cycling = false) ⇒ Object (protected)

Reset the pattern to the beginning

Parameters:

  • is_cycling (Boolean) (defaults to: false) —

    true when #next is performing a cycle back to the beginning of the Pattern. false for a normal #rewind



17
18
19
20
 
# File 'lib/mtk/patterns/palindrome.rb', line 17

def rewind_or_cycle(is_cycling=false)
  @direction = 1
  super
end