Class: Diff::LCS::ContextChange

Inherits:
Change
  • Object
show all
Defined in:
lib/diff/lcs/change.rb

Overview

Represents a contextual change. Contains the position and values of the elements in the old and the new sequenced enumerables as well as the action taken.

Constant Summary

Constants inherited from Change

Diff::LCS::Change::VALID_ACTIONS

Instance Attribute Summary collapse

Attributes inherited from Change

#action, #element, #position

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Change

#adding?, #changed?, #deleting?, #finished_a?, #finished_b?, #unchanged?, valid_action?

Constructor Details

#initialize(*args) ⇒ ContextChange

Returns a new instance of ContextChange.



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# File 'lib/diff/lcs/change.rb', line 111

def initialize(*args)
  @action, @old_position, @old_element, @new_position, @new_element = *args

  unless Diff::LCS::Change.valid_action?(@action)
    raise "Invalid Change Action '#{@action}'"
  end
  unless @old_position.nil? or @old_position.kind_of? Fixnum
    raise "Invalid (Old) Position Type"
  end
  unless @new_position.nil? or @new_position.kind_of? Fixnum
    raise "Invalid (New) Position Type"
  end
end

Instance Attribute Details

#new_element ⇒ Object (readonly)

Returns the new element being changed.



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# File 'lib/diff/lcs/change.rb', line 109

def new_element
  @new_element
end

#new_position ⇒ Object (readonly)

Returns the new position being changed.



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# File 'lib/diff/lcs/change.rb', line 105

def new_position
  @new_position
end

#old_element ⇒ Object (readonly)

Returns the old element being changed.



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# File 'lib/diff/lcs/change.rb', line 107

def old_element
  @old_element
end

#old_position ⇒ Object (readonly)

Returns the old position being changed.



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# File 'lib/diff/lcs/change.rb', line 103

def old_position
  @old_position
end

Class Method Details

.from_a(arr) ⇒ Object 



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# File 'lib/diff/lcs/change.rb', line 136

def self.from_a(arr)
  Diff::LCS::Change.from_a(arr)
end

.simplify(event) ⇒ Object

Simplifies a context change for use in some diff callbacks. ‘<’ actions are converted to ‘-’ and ‘>’ actions are converted to ‘+’.



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# File 'lib/diff/lcs/change.rb', line 142

def self.simplify(event)
  ea = event.to_a

  case ea[0]
  when '-'
    ea[2][1] = nil
  when '<'
    ea[0] = '-'
    ea[2][1] = nil
  when '+'
    ea[1][1] = nil
  when '>'
    ea[0] = '+'
    ea[1][1] = nil
  end

  Diff::LCS::ContextChange.from_a(ea)
end

Instance Method Details

#<=>(other) ⇒ Object 



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# File 'lib/diff/lcs/change.rb', line 169

def <=>(other)
  r = @action <=> other.action
  r = @old_position <=> other.old_position if r.zero?
  r = @new_position <=> other.new_position if r.zero?
  r = @old_element <=> other.old_element if r.zero?
  r = @new_element <=> other.new_element if r.zero?
  r
end

#==(other) ⇒ Object 



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# File 'lib/diff/lcs/change.rb', line 161

def ==(other)
  (@action == other.action) and
  (@old_position == other.old_position) and
  (@new_position == other.new_position) and
  (@old_element == other.old_element) and
  (@new_element == other.new_element)
end

#inspect(*args) ⇒ Object 



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# File 'lib/diff/lcs/change.rb', line 132

def inspect(*args)
  to_a.inspect
end

#to_a ⇒ Object 



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# File 'lib/diff/lcs/change.rb', line 125

def to_a
  [ @action,
    [ @old_position, @old_element ],
    [ @new_position, @new_element ]
  ]
end