Handle singe-apostrophe escapes

lib/message_format/parser.rb

@@ -94,6 +94,7 @@ def parse_text ( parent_type )
             (is_arg_style and is_whitespace(char))
           )
             text << char
+            found_closing_quote = false
             while @index + 1 < @length
               @index += 1
               char = @pattern[@index]
@@ -102,11 +103,17 @@ def parse_text ( parent_type )
                 @index += 1
               elsif char == '\'' # end of quoted
                 @index += 1
+                found_closing_quote = true
                 break
               else
                 text << char
               end
             end
+            # If no closing quote was found, increment past the last character
+            # to avoid reprocessing it in the outer loop
+            if !found_closing_quote
+              @index += 1
+            end
           else # lone ' is just a '
             text << '\''
             # already incremented

spec/message_format_spec.rb

@@ -33,6 +33,13 @@
       expect(message).to eql('This isn\'t a {\'simple\'} \'string\'')
     end
 
+    it 'handles escaped single apostrophe escapes' do
+      pattern = 'Hello \'{literal}!'
+      message = MessageFormat.new(pattern, 'en-US').format()
+
+      expect(message).to eql('Hello {literal}!')
+    end
+
     it 'accepts arguments' do
       pattern = 'x{ arg }z'
       message = MessageFormat.new(pattern, 'en-US').format({ :arg => 'y' })