implement/extend

Weeding.py

 import string
 import os
 
-##################### Weeding ##########################################
+##################### Weeding after scanning ##########################################
+def weedTokens(tokens, file):
+    result = fileNameCheck(tokens, file)
+    result += extendCheck(tokens)
+    return result
+
+
 def fileNameCheck(tokens, f):
     fileName = os.path.basename(f).split('.java')[0]
 
@@ -9,13 +15,26 @@ def fileNameCheck(tokens, f):
     for t in tokens:
         if check:
             if (t.lex != fileName):
-                print(t.lex, fileName)
-                return ("ERROR: Class or Interface name should be the same as file name.")
-            return None
+                return ("ERROR: Class or Interface name should be the same as file name. " + t.lex + "  " +  fileName + "\n")
+            return ""
         if t.name == 'INTERFACE' or t.name == 'CLASS':
             check = True
-    return None
+    return ""
+
+def extendCheck(tokens):
+    check = False
+    for t in tokens:
+        if check:
+            if (not t.lex.startswith('java.' )):
+                return ("ERROR: Can not extend/implement class type " +  t.lex + ".  \n")
+            return ""
+        if t.name == 'EXTENDS' or t.name == 'IMPLEMENTS':
+            check = True
+    return ""
+
+
 
+######################## Weeding after parsing ################################
 
 
 # node: Node[]

joosc.py

@@ -5,22 +5,28 @@ from os.path import isfile, join
 
 from Scanning import scan
 from Parsing import parse
+from Weeding import weedTokens
 
 
 def main():
     inputfile = sys.argv[1]
     content = open(inputfile, "r").read()
-    
+
     # Scanning
     try:
         (tokens, errorString) = scan(content)
     except:
         return 42
-        
+
     # Error in Scanning
     if tokens is None:
         return 42
 
+    # Weed the tokens
+    weeds = weedTokens(tokens, inputfile)
+    if weeds != "":
+        return 42
+
     # Parsing
     try:
         (steps, error) = parse(tokens)
@@ -34,4 +40,4 @@ def main():
     print("success in scanning and parsing")
     return 0
 
-main()
\ No newline at end of file
+main()