🖊️ Add error for else statement without if statement #5099 (#5391)

Fixes #5099 Add a custom error in levels 5-7 when there is an `else` statement when there is no `if` right before it. **How to test** Run the following snippets in levels 5-7 and check that the custom error is appropriate: ``` if answer is yes print 'great!' print 'correct' else print 'wrong' ``` ``` else print 'wrong' ```
hedyorg · Apr 16, 2024 · d888124 · d888124
1 parent 8021295
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diff --git a/content/error-messages.txt b/content/error-messages.txt
@@ -34,6 +34,7 @@ gettext('Lonely Text')
 gettext('Runtime Value Error')
 gettext('Runtime Values Error')
 gettext('Runtime Index Error')
+gettext('Else Without If Error')
 gettext('ask_needs_var')
 gettext('no_more_flat_if')
 gettext('echo_out')

diff --git a/exceptions.py b/exceptions.py
@@ -383,4 +383,9 @@ def __init__(self, name):
         super().__init__('Runtime Index Error', name=name)
 
 
+class ElseWithoutIfException(HedyException):
+    def __init__(self, line_number):
+        super().__init__('Else Without If Error', line_number=line_number)
+
+
 HEDY_EXCEPTIONS = {name: cls for name, cls in globals().items() if inspect.isclass(cls)}
diff --git a/grammars/level5-Additions.lark b/grammars/level5-Additions.lark
@@ -4,7 +4,7 @@ _empty_program: (_EOL | _SPACE)*
 _non_empty_program: _EOL* (command | error_invalid) _SPACE* (_EOL+ command _SPACE*)* _EOL* //lines may end on spaces and might be separated by many newlines
 
 //placing assign after print means print is will print 'is' and print is Felienne will print 'is Felienne'
-command: += assign_button | if_pressed_else | error_if_pressed_missing_else | if_pressed_without_else | ifelse | ifs -= error_invalid >> assign
+command: += assign_button | if_pressed_else | error_if_pressed_missing_else | if_pressed_without_else | ifelse | ifs | error_else_no_if -= error_invalid >> assign
 _if_less_command: print | ask | play | turtle | assign_button | assign_list | add | remove | sleep | error_print_no_quotes | assign
 
 // error_invalid is moved from to command to program, so that command rules have priority over error_invalid
@@ -26,9 +26,11 @@ if_pressed_without_else: _IF (LETTER_OR_NUMERAL | var) _IS _PRESSED _EOL* _if_le
 error_if_pressed_missing_else: if_pressed_without_else
 
 _if_clause: _IF (condition (_SPACE+ _EOL* | _SPACE* _EOL+) | condition_spaces _SPACE* _EOL+ | error_condition) _if_less_command
+_else_clause: _ELSE (_SPACE+ _EOL* | _SPACE* _EOL+) _if_less_command
 error_condition: condition_spaces _SPACE
-ifelse: _if_clause (_SPACE+ _EOL* | _SPACE* _EOL+) _ELSE (_SPACE+ _EOL* | _SPACE* _EOL+) _if_less_command
+ifelse: _if_clause (_SPACE+ _EOL* | _SPACE* _EOL+) _else_clause
 ifs: _if_clause // 'if' is a reserved word in Python, hence the name of the rule is 'ifs'
+error_else_no_if.-1: _else_clause
 
 condition_spaces: textwithoutspaces _IS textwithoutspaces (_SPACE textwithoutspaces)+
 condition: equality_check | in_list_check | not_in_list_check

diff --git a/grammars/level6-Additions.lark b/grammars/level6-Additions.lark
@@ -2,7 +2,7 @@ _print_ask_argument: (_SPACE | quoted_text | list_access | expression | print_ex
 ?print_expression: var_access_print | error_unsupported_number | INT
 
 // redefining it entirely since it has many order-depending rules
-command: clear | error_non_decimal | print | turtle | play | add | remove | error_add_missing_to | error_remove_missing_from | sleep | error_print_no_quotes | error_print_one_quote_only | if_pressed_else | error_if_pressed_missing_else | if_pressed_without_else | ifelse | ifs | ask | error_ask_no_quotes| assign_button | assign | assign_list | error_invalid_space | error_text_no_print | empty_line
+command: clear | error_non_decimal | print | turtle | play | add | remove | error_add_missing_to | error_remove_missing_from | sleep | error_print_no_quotes | error_print_one_quote_only | if_pressed_else | error_if_pressed_missing_else | if_pressed_without_else | ifelse | ifs | error_else_no_if | ask | error_ask_no_quotes | assign_button | assign | assign_list | error_invalid_space | error_text_no_print | empty_line
 _if_less_command: print | turtle | play | add | remove | sleep | error_print_no_quotes | error_print_one_quote_only | ask | error_ask_no_quotes | assign_button | assign | assign_list
 
 //splitting these commands into two rules, one for equals and one for is so they can be properly handled in the translator

diff --git a/grammars/level8-Additions.lark b/grammars/level8-Additions.lark
@@ -1,4 +1,4 @@
-command: += error_repeat_dep_8 | error_ifelse | if_pressed_without_else | if_pressed if_pressed_elses? | ifs elses? -= error_invalid_space | ifelse
+command: += error_repeat_dep_8 | error_ifelse | if_pressed_without_else | if_pressed if_pressed_elses? | ifs elses? -= error_invalid_space | ifelse | error_else_no_if
 
 repeat.1: _REPEAT (INT | var_access) _TIMES _SPACE? _EOL (_SPACE command) (_EOL _SPACE command)* _EOL? _END_BLOCK
 error_repeat_dep_8: _REPEAT (INT | var_access) _TIMES _SPACE command

diff --git a/hedy.py b/hedy.py
@@ -1253,6 +1253,9 @@ def error_ifelse(self, meta, args):
             tip='no_more_flat_if',
             line_number=meta.line)
 
+    def error_else_no_if(self, meta, args):
+        raise exceptions.ElseWithoutIfException(meta.line)
+
     def error_for_missing_in(self, meta, args):
         raise exceptions.MissingAdditionalCommand(command='for', missing_command='in', line_number=meta.line)
 

diff --git a/messages.pot b/messages.pot
@@ -23,6 +23,9 @@ msgstr ""
 msgid "Cyclic Var Definition"
 msgstr ""
 
+msgid "Else Without If Error"
+msgstr ""
+
 msgid "Function Undefined"
 msgstr ""
 

diff --git a/tests/Tester.py b/tests/Tester.py
@@ -341,7 +341,8 @@ def single_level_tester(
             skipped_exceptions = [
                 hedy.exceptions.ParseException, hedy.exceptions.CodePlaceholdersPresentException,
                 hedy.exceptions.TooFewIndentsStartLevelException, hedy.exceptions.TooManyIndentsStartLevelException,
-                hedy.exceptions.NoIndentationException, hedy.exceptions.IndentationException
+                hedy.exceptions.NoIndentationException, hedy.exceptions.IndentationException,
+                hedy.exceptions.ElseWithoutIfException
             ]
 
             if translate and exception not in skipped_exceptions and skipped_mappings is None:

diff --git a/tests/test_level/test_level_05.py b/tests/test_level/test_level_05.py
@@ -684,6 +684,24 @@ def test_if_equality_print_else_print_bengali(self):
 
         self.single_level_tester(code=code, expected=expected)
 
+    def test_else_without_if_gives_error(self):
+        code = "else print 'wrong'"
+
+        self.multi_level_tester(code=code, exception=hedy.exceptions.ElseWithoutIfException, max_level=7)
+
+    def test_else_without_if_indentation_gives_error(self):
+        code = textwrap.dedent("""\
+            if answer is yes print 'great!'
+            print 'correct'
+            else print 'wrong'""")
+
+        self.multi_level_tester(
+            code=code,
+            exception=hedy.exceptions.ElseWithoutIfException,
+            max_level=7,
+            skip_faulty=False
+        )
+
     #
     # combined tests
     #

diff --git a/translations/ar/LC_MESSAGES/messages.po b/translations/ar/LC_MESSAGES/messages.po
@@ -26,6 +26,9 @@ msgstr "لقد حاولت استخدام المتغير {name} في السطر {
 msgid "Cyclic Var Definition"
 msgstr "يجب أن تضبط قيمة المتغير `{variable}` قبل أن تستعمله على الجانب الأيسر من من الأمر هو."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/bg/LC_MESSAGES/messages.po b/translations/bg/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/bn/LC_MESSAGES/messages.po b/translations/bn/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it।"

diff --git a/translations/ca/LC_MESSAGES/messages.po b/translations/ca/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Has intentat utilitzar la variable {name} a la línia {access_line_numbe
 msgid "Cyclic Var Definition"
 msgstr "El nom `{variable}` ha de ser definit abans d'utilitzar-lo a la dreta de la comanda `{is}`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/cs/LC_MESSAGES/messages.po b/translations/cs/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/cy/LC_MESSAGES/messages.po b/translations/cy/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/da/LC_MESSAGES/messages.po b/translations/da/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/de/LC_MESSAGES/messages.po b/translations/de/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Du hast versucht die Variable {name} in Zeile {access_line_number} zu be
 msgid "Cyclic Var Definition"
 msgstr "Der Name `{variable}` muss gesetzt werden, bevor du ihn auf der rechten Seite des `{is}` Befehls verwenden kannst."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/el/LC_MESSAGES/messages.po b/translations/el/LC_MESSAGES/messages.po
@@ -26,6 +26,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "Το όνομα `{variable}` πρέπει να οριστεί για να μπορέσεις να το χρησιμοποιήσεις στη δεξιά πλευρά της εντολής is"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/en/LC_MESSAGES/messages.po b/translations/en/LC_MESSAGES/messages.po
@@ -24,6 +24,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr "On line {line_number} you used an `{else}` but there is no `{if}` on the line before it."
+
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."
 

diff --git a/translations/eo/LC_MESSAGES/messages.po b/translations/eo/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Vi provis uzi la variablon {name} je la linio {access_line_number}, sed
 msgid "Cyclic Var Definition"
 msgstr "La nomo `{variable}` bezonas ricevi valoron antaŭ vi povas uzi ĝin maldekstre de la komando `{is}`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 msgid "Function Undefined"
 msgstr "Vi provis uzi la funkcion {name}, sed vi ne difinis ĝin."
 

diff --git a/translations/es/LC_MESSAGES/messages.po b/translations/es/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Has intentado usar la variable {name} en la línea {access_line_number},
 msgid "Cyclic Var Definition"
 msgstr "Debes declarar la variable `{variable}` antes de poder usarla en el lado derecho del comando `{is}`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 msgid "Function Undefined"
 msgstr "Has intentado utilizar la función {name}, pero no la has definido."
 

diff --git a/translations/et/LC_MESSAGES/messages.po b/translations/et/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/fa/LC_MESSAGES/messages.po b/translations/fa/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/fi/LC_MESSAGES/messages.po b/translations/fi/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/fr/LC_MESSAGES/messages.po b/translations/fr/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Tu as essayé d'utiliser la variable {name} à la ligne {access_line_num
 msgid "Cyclic Var Definition"
 msgstr "Le nom `{variable}` doit être défini avant que tu puisses l’utiliser à droite de la commande `is`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/fy/LC_MESSAGES/messages.po b/translations/fy/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/he/LC_MESSAGES/messages.po b/translations/he/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "ניסיתם להשתמש במשתנה {name} בשורה {access_line_nu
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the is command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/hi/LC_MESSAGES/messages.po b/translations/hi/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "आपने लाइन {access_line_number} पर वेरिएब
 msgid "Cyclic Var Definition"
 msgstr "नाम `{variable}` को is कमांड के दाईं ओर उपयोग करने से पहले सेट करने की आवश्यकता है"
 
+msgid "Else Without If Error"
+msgstr ""
+
 msgid "Function Undefined"
 msgstr "आपने फ़ंक्शन {name} का उपयोग करने का प्रयास किया, लेकिन आपने इसे परिभाषित नहीं किया।"
 

diff --git a/translations/hu/LC_MESSAGES/messages.po b/translations/hu/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "A {name} nevű változót a {access_line_number}. sorban próbáltad has
 msgid "Cyclic Var Definition"
 msgstr "Először be kell állítanod a `{variable}` nevű változó értékét, csak utána tudod az `{is}` parancs jobb oldalán használni"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/ia/LC_MESSAGES/messages.po b/translations/ia/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/id/LC_MESSAGES/messages.po b/translations/id/LC_MESSAGES/messages.po
@@ -37,6 +37,9 @@ msgstr ""
 msgid "Cyclic Var Definition"
 msgstr "Nama `{variable}` perlu disetel sebelum Anda dapat menggunakannya di sisi kanan perintah `{is}`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/it/LC_MESSAGES/messages.po b/translations/it/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Hai provato a utilizzare la variabile {name} sulla riga {access_line_num
 msgid "Cyclic Var Definition"
 msgstr "Il nome `{variable}` deve essere impostato prima di poterlo utilizzare sul lato destro del comando `{is}`."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/ja/LC_MESSAGES/messages.po b/translations/ja/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "あなたは {name} という変数を{access_line_number}行で使お
 msgid "Cyclic Var Definition"
 msgstr "この名前 `{variable}`は、`{is}` コマンドの右側で使う前に定めて下さい。"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/kmr/LC_MESSAGES/messages.po b/translations/kmr/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/ko/LC_MESSAGES/messages.po b/translations/ko/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "{access_line_number} 라인에서 {name} 변수를 사용하려고 했
 msgid "Cyclic Var Definition"
 msgstr "`{is}` 명령어의 오른쪽에서 이름 `{variable}`을(를) 설정해야 사용할 수 있습니다."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/mi/LC_MESSAGES/messages.po b/translations/mi/LC_MESSAGES/messages.po
@@ -27,6 +27,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "The name `{variable}` needs to be set before you can use it on the right-hand side of the `{is}` command."
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/nb_NO/LC_MESSAGES/messages.po b/translations/nb_NO/LC_MESSAGES/messages.po
@@ -26,6 +26,9 @@ msgstr "You tried to use the variable {name} on line {access_line_number}, but y
 msgid "Cyclic Var Definition"
 msgstr "Variabelen `{variable}` må opprettes og gis en verdi før du kan bruke den på høyre siden av hvis-kommandoen"
 
+msgid "Else Without If Error"
+msgstr ""
+
 #, fuzzy
 msgid "Function Undefined"
 msgstr "You tried to use the function {name}, but you didn't define it."

diff --git a/translations/nl/LC_MESSAGES/messages.po b/translations/nl/LC_MESSAGES/messages.po
@@ -25,6 +25,9 @@ msgstr "Je probeerde de variabele {name} te gebruiken op regel {access_line_numb
 msgid "Cyclic Var Definition"
 msgstr "De variabele `{variable}` moet worden ingesteld voor je die aan de rechterkant van een `{is}` mag gebruiken."
 
+msgid "Else Without If Error"
+msgstr ""
+
 msgid "Function Undefined"
 msgstr "Je gebruikt de functie {name} te gebruiken, maar je hebt die niet gedefinieerd."