Add support to backslashed strings in CodeHelpers' #complete_expression?

lib/method_source/code_helpers.rb

@@ -71,8 +71,7 @@ def complete_expression?(str)
         eval("BEGIN{throw :valid}\n#{str}")
       end
 
-      # Assert that a line which ends with a , or \ is incomplete.
-      str !~ /[,\\]\s*\z/
+      no_ending_comma?(str) || backslashed_string?(str)
     rescue IncompleteExpression
       false
     ensure
@@ -81,6 +80,32 @@ def complete_expression?(str)
 
     private
 
+    # Determine if a representation of a string as a string ends with comma.
+    #
+    # @param [String] The string to validate.
+    # @return [Boolean] Whether or not the string ends with comma
+    def no_ending_comma?(str)
+      str !~ /[,\\]\s*\z/
+    end
+
+    # Determine if a backslashed string as a string,
+    #   after removing the matching backslashes, ends with
+    #   comma or a backslash.
+    #
+    # @param [String] The string to validate.
+    # @return [Boolean] Whether or not the remaining string ends with
+    #   comma or backslash.
+    #
+    # @example
+    #   backslashed_string?("%\a\\") #=> true
+    #   backslashed_string?("%\\\\") #=> true
+    #   backslashed_string?("%\abc\\") #=> true
+    def backslashed_string?(str)
+      remaining_str = str[/%\\(.*)\\\s*\z/, 1]
+
+      !remaining_str.nil? && remaining_str !~ /[,\\]\s*\z/
+    end
+
     # Get the first expression from the input.
     #
     # @param [Array<String>]  lines

test/test_code_helpers.rb

@@ -23,6 +23,16 @@
     end
   end
 
+  [
+    '%\a\\',
+    '%\abc\\',
+    '%\\\\',
+  ].each do |line|
+    it "should not complain on backslashed strings: #{line}" do
+      @tester.complete_expression?(line).should == true
+    end
+  end
+
   [
     ["end"],
     ["puts )("],