Raise instead of throw

lib/ahem/ast/function_call.rb

 
     if function.is_a?(AST::FunctionDefinition)
       if @arguments.size != function.parameters.size
-        throw "Arity mismatch in call to function #{function.name}"
+        raise "Arity mismatch in call to function #{function.name}"
       end
 
       function.parameters.each_with_index do |param, i|

lib/ahem/ast/index.rb

         if key.to_i == key && object.size > key
           object[key]
         elsif key.to_i != key
-          throw "Array index requires integer key"
+          raise "Array index requires integer key"
         elsif object.size <= key
-          throw "Array index out of bounds"
+          raise "Array index out of bounds"
         end
       else
-        throw "Array index requires integer key"
+        raise "Array index requires integer key"
       end
     elsif object.is_a?(Hash)
       if object.has_key?(key)
         object[key]
       else
-        throw "Key #{key} does not exist on object"
+        raise "Key #{key} does not exist on object"
       end
     end
   end

lib/ahem/environment.rb

     if @data.has_key?(name)
       @data[name]
     else
-      throw "Undefined variable #{name}"
+      raise "Undefined variable #{name}"
     end
   end
 

lib/ahem/lexer.rb

       @position += class_name.size
       Token.new(TokenKinds::CLASS_NAME, class_name)
     else
-      throw "Unrecognized character #{source[0]}"
+      raise "Unrecognized character #{source[0]}"
     end
   end
 

lib/ahem/parser.rb

     when TokenKinds::LBRACE
       hash
     else
-      throw "Unexpected token #{token.type}"
+      raise "Unexpected token #{token.type}"
     end
 
     if @current_token.type == TokenKinds::LPAREN
       token
     else
       if token.nil?
-        throw "Unexpected #{token.type} - expected #{type}"
+        raise "Unexpected #{token.type} - expected #{type}"
       else
-        throw "Unexpected #{token.type} - expected #{type}"
+        raise "Unexpected #{token.type} - expected #{type}"
       end
     end
   end