fixed the integer checking code

Scanning.py

@@ -494,6 +494,12 @@ def scan(input):
                 if index < indexRange-1:
                     if tokens[index+1].name == 'NUM':
                         return (None, "wrong integer literal: starts with 0")
+            # Checking integer range (does not cover all edge cases)
+            elif token.name == 'NUM' and index > 0 and tokens[index-1].name == 'SUB' and int(token.lex) > 2147483648:
+                return (None, "integer too small")
+            elif token.name == 'NUM' and int(token.lex) > 2147483647 and (index is 0 or tokens[index-1].name is not 'SUB'):
+                return (None, "interger too large")
+
 
             # dealing with keywords in Java but not in Joos
             elif token.name == 'ID' and token.lex in wrongJavaKeyWordDict: