Bugfixes und erste Tests WHILE-Interpreter

info4/kapitel-8/Interpreter/test_while_interpreter.py

+from whileinterpreter import interpret
+from test_loop_interpreter import LOOPInterpreterTest
+import unittest
+
+
+class WHILEInterpreterTest(LOOPInterpreterTest):
+    def test_while_forbidden_identifier(self):
+        with self.assertRaises(SyntaxError):
+            interpret("LOOP x1 DO WHILE x1 != 0 DO x0:=x0+1 END END ")
+
+    def test_while(self):
+        self.assertEqual(interpret('x1:=1; WHILE x1 != 0 DO x0:=2; x1:=x1-1 END'), 2)
+        self.assertEqual(interpret('WHILE x1 /= 0 DO x0:=1 END'), 0)
+        self.assertEqual(interpret('WHILE x1 /= 0 DO WHILE x1 /= 0 DO x0:=2 END END'), 0)
+
+    def test_while_non_zero(self):
+        with self.assertRaises(SyntaxError):
+            interpret("x1:= 1; WHILE x1 /= 1 DO x0:=2 END")
+        with self.assertRaises(SyntaxError):
+            interpret("x1:= 2; WHILE x1 /= 1 DO x0:=2 END")
+        with self.assertRaises(SyntaxError):
+            interpret("x1:= 1; WHILE x1 /= 0 DO WHILE x1 /= 1 DO x0:=2 END END")

info4/kapitel-8/Interpreter/whileinterpreter.py

@@ -9,8 +9,8 @@ class WHILEInterpreter(LOOPInterpreter):
                                (re.compile(r'x\d+'), 'IDENTIFIER'),
                                (re.compile(r'\+'), 'PLUS'),
                                (re.compile(r'-'), 'MINUS'),
-                               (re.compile(r':=|≔|!='), 'EQUALS'),
-                               (re.compile(r'/=|≠'), 'NOTEQUALS'),
+                               (re.compile(r':=|≔'), 'EQUALS'),
+                               (re.compile(r'/=|≠|!='), 'NOTEQUALS'),
                                (re.compile(r'LOOP'), 'LOOP'),
                                (re.compile(r'WHILE'), 'WHILE'),
                                (re.compile(r'DO'), 'DO'),
@@ -22,7 +22,7 @@ class WHILEInterpreter(LOOPInterpreter):
                                (re.compile(r'[^\n]*'), 'UNKNOWN')]
 
     def process_program(self, forbidden_identifiers, current_token):
-        if current_token is None or current_token.k not in ['IDENTIFIER', 'LOOP']:
+        if current_token is None or current_token.k not in ['IDENTIFIER', 'LOOP', 'WHILE']:
             self.error_handler.handle_error("Keine passende Anweisung gefunden\n" +
                                             "Erwartet: IDENTIFIER (x0, x1, ...) oder LOOP")
         elif current_token.k == 'IDENTIFIER':
@@ -34,7 +34,7 @@ class WHILEInterpreter(LOOPInterpreter):
         return current_token
 
     def verify_program(self, forbidden_identifiers, current_token):
-        if current_token is None or current_token.k not in ['IDENTIFIER', 'LOOP']:
+        if current_token is None or current_token.k not in ['IDENTIFIER', 'LOOP', 'WHILE']:
             self.error_handler.handle_error("Keine passende Anweisung gefunden\n" +
                                             "Erwartet: IDENTIFIER (x0, x1, ...) oder LOOP")
         elif current_token.k == 'IDENTIFIER':
@@ -61,6 +61,9 @@ class WHILEInterpreter(LOOPInterpreter):
         if not int(zero_token.v) == 0:
             self.error_handler.handle_error('0 in WHILE erwartet.')
 
+        if not self.next_nonempty_token("WHILE", "DO").k == 'DO':
+            self.error_handler.handle_error('DO in WHILE erwartet.')
+
         if identifier_token.v in self.values:
             while_value = int(self.values.get(identifier_token.v))
         else:
@@ -115,6 +118,9 @@ class WHILEInterpreter(LOOPInterpreter):
         if not int(zero_token.v) == 0:
             self.error_handler.handle_error('0 in WHILE erwartet.')
 
+        if not self.next_nonempty_token("WHILE", "DO").k == 'DO':
+            self.error_handler.handle_error('DO in WHILE erwartet.')
+
         end_found = False
         while not end_found:
             token = self.verify_program(forbidden_identifiers, self.next_token())
@@ -129,4 +135,4 @@ class WHILEInterpreter(LOOPInterpreter):
 
 def interpret(program):
     interpreter = WHILEInterpreter()
-    interpreter.interpret(program)
\ No newline at end of file
+    return interpreter.interpret(program)