Class: IrwiMod::Comparators::DiffLcs
- Defined in:
- lib/irwi_mod/comparators/diff_lcs.rb
Instance Method Summary collapse
- #build_changes(old_text, new_text) ⇒ Object
-
#initialize ⇒ DiffLcs
constructor
A new instance of DiffLcs.
Methods inherited from Base
Constructor Details
#initialize ⇒ DiffLcs
Returns a new instance of DiffLcs.
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# File 'lib/irwi_mod/comparators/diff_lcs.rb', line 5 def initialize super require 'diff/lcs' end |
Instance Method Details
#build_changes(old_text, new_text) ⇒ Object
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# File 'lib/irwi_mod/comparators/diff_lcs.rb', line 11 def build_changes( old_text, new_text ) diffs = Diff::LCS.sdiff( (old_text || '').mb_chars, (new_text || '').mb_chars ) # Building symmetric diff sequence changes = [] # Array for our result changes diffs.each do |change| case change.action when '=' then if !changes.empty? && changes.last.action == '=' # Append to last not changed span, if exists changes.last.value << change.old_element else changes << new_not_changed( change.old_element ) end when '+' then if !changes.empty? && changes.last.action == '+' # Append to last addition, if exists changes.last.new_value << change.new_element elsif !changes.empty? && changes.last.action == '!' # Append to last replace, if exists (it's necessary when replacing short string with a new long) changes.last.new_value << change.new_element else changes << new_changed( '+', nil, change.new_element ) end when '-' then if !changes.empty? && changes.last.action == '-' # Append to last deletion, if exists changes.last.old_value << change.old_element else changes << new_changed( '-', change.old_element, nil ) end when '!' then if !changes.empty? && changes.last.action == '!' # Append to last replace, if exists changes.last.old_value << change.old_element changes.last.new_value << change.new_element else changes << new_changed( '!', change.old_element, change.new_element ) end end end changes end |