lib/dolos/parsers.rb in dolos-0.1.2 vs lib/dolos/parsers.rb in dolos-0.1.3

@@ -8,18 +8,21 @@
         utf8_str = str.encode('UTF-8')
         if state.input.matches?(utf8_str)
           Success.new(utf8_str, str.bytesize)
         else
           advanced = state.input.offset
+          got_error = state.input.io.string.byteslice(state.input.backup, advanced)
           state.input.rollback
           Failure.new(
-            "Expected #{str.inspect} but got #{state.input.io.string.inspect}",
-            advanced
+            "Expected #{str.inspect} but got #{got_error.inspect}",
+            advanced,
+            state
           )
         end
       end
     end
+
     alias_method :c, :string
 
     def regex(pattern)
       Parser.new do |state|
         state.input.mark_offset
@@ -28,17 +31,17 @@
         else
           advanced = state.input.offset
           state.input.rollback
           Failure.new(
             "Expected pattern #{pattern.inspect} but got #{state.input.io.string.inspect}",
-            advanced
+            advanced,
+            state
           )
         end
       end
     end
 
-
     def any_char
       Parser.new do |state|
         state.input.mark_offset
 
         char, = state.input.peek(1)
@@ -46,11 +49,15 @@
         if char && !char.empty?
           Success.new(char, char.bytesize)
         else
           advanced = state.input.offset
           state.input.rollback
-          Failure.new('Expected any character but got end of input', advanced)
+          Failure.new(
+            'Expected any character but got end of input',
+            advanced,
+            state
+          )
         end
       end
     end
 
     # Matches any character in a string
@@ -69,11 +76,12 @@
         else
           advanced = state.input.offset
           state.input.rollback
           Failure.new(
             "Expected one of #{characters_array.inspect} but got #{char.inspect}",
-            advanced
+            advanced,
+            state
           )
         end
       end
     end
 
@@ -90,10 +98,14 @@
           state.input.advance(bytesize)
         end
 
         if buffer.empty?
           advanced = state.input.offset
-          Failure.new("Predicate never returned true", advanced)
+          Failure.new(
+            "Predicate never returned true",
+            advanced,
+            state
+          )
         else
           Success.new(buffer, 0)
         end
       end
     end