Zuweisung von Zahl zu Variable und LOOPs mit 0 Durchläufen funktionieren jetzt richtig

info4/kapitel-8/Interpreter/interpreter.py

@@ -23,7 +23,7 @@ def process_assignment(token_queue, position, value_list, forbidden_identifiers)
         value_1 = 0
 
     if token_queue[position + 2].k == 'NUMBER':
-        value_1 += int(token_queue[position + 2].v)
+        value_1 = int(token_queue[position + 2].v)
         value_list.update({identifier_1: value_1})
         return position + 3, value_list
 
@@ -31,7 +31,8 @@ def process_assignment(token_queue, position, value_list, forbidden_identifiers)
         raise SyntaxError("IDENTIFIER in Zuweisung erwartet.")
     identifier_2 = token_queue[position + 2].v
     if identifier_2 in forbidden_identifiers:
-        raise Exception("Identifier " + identifier_2 + " ist bereits in Loop vorhanden und darf nicht verwendet werden.")
+        raise Exception(
+            "Identifier " + identifier_2 + " ist bereits in Loop vorhanden und darf nicht verwendet werden.")
 
     if identifier_2 in value_list:
         value_2 = value_list.get(identifier_2)
@@ -49,29 +50,124 @@ def process_assignment(token_queue, position, value_list, forbidden_identifiers)
     value_list.update({identifier_1: value_1})
     return position + 5, value_list
 
+
+def verify_assignment(token_queue, position, forbidden_identifiers):
+    identifier_1 = token_queue[position].v
+    if identifier_1 in forbidden_identifiers:
+        raise Exception("Identifier " + identifier_1 + "ist bereits in Loop vorhanden und darf nicht verwendet werden.")
+    if not token_queue[position + 1].k == 'EQUALS':
+        raise SyntaxError(":= in Zuweisung erwartet.")
+
+    if token_queue[position + 2].k == 'NUMBER':
+        return position + 3
+
+    if not token_queue[position + 2].k == 'IDENTIFIER':
+        raise SyntaxError("IDENTIFIER in Zuweisung erwartet.")
+    identifier_2 = token_queue[position + 2].v
+    if identifier_2 in forbidden_identifiers:
+        raise Exception(
+            "Identifier " + identifier_2 + " ist bereits in Loop vorhanden und darf nicht verwendet werden.")
+
+    if not token_queue[position + 4].k == 'NUMBER':
+        raise SyntaxError("NUMBER in Zuweisung erwartet.")
+    if not token_queue[position + 3].k in ['PLUS', 'MINUS']:
+        raise SyntaxError("PLUS oder MINUS in Zuweisung erwartet.")
+
+    return position + 5
+
+
+def verify_loop(token_queue, position, forbidden_identifiers):
+    identifier_token = token_queue[position + 1]
+    if not identifier_token.k == 'IDENTIFIER':
+        raise SyntaxError('IDENTIFIER in LOOP erwartet.')
+    if identifier_token.v in forbidden_identifiers:
+        raise SyntaxError(
+            "Identifier " + identifier_token.v + "ist bereits in Loop vorhanden und darf nicht verwendet werden.")
+    if not token_queue[position + 2].k == 'DO':
+        raise SyntaxError('DO in LOOP erwartet.')
+
+    forbidden_identifiers.append(identifier_token.v)
+
+    end_found = False
+    while not end_found:
+        position = verify_program(token_queue, position, forbidden_identifiers)
+        if token_queue[position].k == 'SEMICOLON':
+            position = position + 1
+            continue
+        elif token_queue[position].k == 'END':
+            end_found = True
+        else:
+            raise SyntaxError("SEMICOLON oder END erwartet.")
+
+    forbidden_identifiers.remove(identifier_token.v)
+    return position + 1
+
+
+def verify_program(token_queue, position, forbidden_identifiers):
+    current_key = token_queue[position].k
+    if current_key == 'IDENTIFIER':
+        try:
+            current_position = verify_assignment(token_queue, position, forbidden_identifiers)
+        except IndexError:
+            raise Exception("Frühzeitiges Ende einer Zuweisung.")
+    elif current_key == 'LOOP':
+        try:
+            current_position = verify_loop(token_queue, position, forbidden_identifiers)
+        except IndexError:
+            raise Exception("Frühzeitiges Ende eines LOOPs")
+    else:
+        raise SyntaxError("Keine passende Anweisung gefunden")
+    return current_position
+
+
 def process_loop(token_queue, position, value_list, forbidden_identifiers):
     identifier_token = token_queue[position + 1]
     if not identifier_token.k == 'IDENTIFIER':
         raise SyntaxError('IDENTIFIER in LOOP erwartet.')
+    if identifier_token.v in forbidden_identifiers:
+        raise SyntaxError(
+            "Identifier " + identifier_token.v + "ist bereits in Loop vorhanden und darf nicht verwendet werden.")
     if not token_queue[position + 2].k == 'DO':
         raise SyntaxError('DO in LOOP erwartet.')
 
+    if identifier_token.v in value_list:
         number_of_loops = int(value_list.get(identifier_token.v))
+    else:
+        number_of_loops = 0
     saved_position = position + 3
     forbidden_identifiers.append(identifier_token.v)
+
+    # TODO increment position without changing values when number of loops = 0
+    if number_of_loops == 0:
+        end_found = False
+        position = saved_position
+        while not end_found:
+            position = verify_program(token_queue, position, forbidden_identifiers)
+            if token_queue[position].k == 'SEMICOLON':
+                position = position + 1
+                continue
+            elif token_queue[position].k == 'END':
+                end_found = True
+            else:
+                raise SyntaxError("SEMICOLON oder END erwartet.")
+
     for index in range(number_of_loops):
         position = saved_position
         end_found = False
-        while(not end_found):
+        while not end_found:
             position, value_list = process_program(token_queue, position, value_list, forbidden_identifiers)
             if token_queue[position].k == 'SEMICOLON':
                 position = position + 1
                 continue
             elif token_queue[position].k == 'END':
                 end_found = True
-            else: raise SyntaxError("SEMICOLON oder END erwartet.")
+            else:
+                raise SyntaxError("SEMICOLON oder END erwartet.")
+
+    forbidden_identifiers.remove(identifier_token.v)
     return position + 1, value_list
 
+
 def process_program(token_queue, position, value_list, forbidden_identifiers):
     current_key = token_queue[position].k
     if current_key == 'IDENTIFIER':
@@ -88,6 +184,7 @@ def process_program(token_queue, position, value_list, forbidden_identifiers):
         raise SyntaxError("Keine passende Anweisung gefunden")
     return current_position, values
 
+
 def interpret(program):
     tokens = lexer.tokenize(program)
     current_position = 0
@@ -103,4 +200,7 @@ def interpret(program):
         return values.get("x0")
     return 0
 
+
 print(interpret(loop_program))
+print(interpret('''x1:= 2; 
+LOOP x1 DO x2 := 2 END; x0 := x2 + 1'''))