Class: MTK::Patterns::ForEach

Inherits:
Pattern
  • Object
show all
Defined in:
lib/mtk/patterns/for_each.rb

Overview

For each value in the first sub-pattern, iterate over the second sub-pattern and chain the resulting values.

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 Pattern

#advance, #empty?, from_a, #initialize, #max_cycles_exceeded?, #max_elements_exceeded?, #min_elements_unmet?, #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::Pattern

Instance Method Details

#next ⇒ Object

Emit the next element in the pattern

Raises:



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# File 'lib/mtk/patterns/for_each.rb', line 9

def next
  @index = 0 if @index < 0

  last_index = @elements.length-1
  while @index <= last_index
    # assume all elements are Patterns, otherwise this construct doesn't really have a point...
    pattern = @elements[@index]
    begin
      element = pattern.next
      value = evaluate_variables(element)

      if @index == last_index # then emit values
        @current = value
        return emit(value)

      else # not last element, so store variables
        @vars.push value
        @index += 1
      end

    rescue StopIteration
      if @index==0
        raise # We're done when the first pattern is done
      else
        pattern.rewind
        @vars.pop
        @index -= 1
      end
    end
  end
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



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# File 'lib/mtk/patterns/for_each.rb', line 46

def rewind_or_cycle(is_cycling=false)
  @vars = []
  @elements.each{|elem| elem.rewind }
  super
end