def diff(options={})
groups = SequenceMatcher.new(@from, @to).grouped_operations
return [] if groups.empty?
return [] if same_content?(groups)
show_context = options[:show_context]
show_context = true if show_context.nil?
result = ["--- #{options[:from_label]}".rstrip,
"+++ #{options[:to_label]}".rstrip]
groups.each do |operations|
result << format_summary(operations, show_context)
operations.each do |args|
operation_tag, from_start, from_end, to_start, to_end = args
case operation_tag
when :replace
result.concat(tag("-", @from[from_start...from_end]))
result.concat(tag("+", @to[to_start...to_end]))
when :delete
result.concat(tag("-", @from[from_start...from_end]))
when :insert
result.concat(tag("+", @to[to_start...to_end]))
when :equal
result.concat(tag(" ", @from[from_start...from_end]))
end
end
end
result
end