errors.rb in antelope-0.3.0

- old
+ new

@@ -1,8 +1,25 @@
 # encoding: utf-8
 
 module Antelope
-
   # Every error in antelope inherits this error class.
   class Error < StandardError
+  end
+
+  # This is used primarily in the {Grammar}; if a rule references a
+  # token (a nonterminal or a terminal) that was not previously
+  # defined, this is raised.
+  class UndefinedTokenError < Error
+  end
+
+  # Used primarily in the {Compiler}, this is raised when the
+  # version requirement of the Ace file doesn't match the running
+  # version of Ace.
+  class IncompatibleVersionError < Error
+  end
+
+  # Primarily used in the {Grammar} (specifically
+  # {Grammar::Generation}), if the grammar could not determine the
+  # generator to use for the generation, it raises this.
+  class NoTypeError < Error
   end
 end