Fix invalid import statement error messages

LourensVeen · LourensVeen · commit 3de13452d14a · 2026-02-27T09:46:54.000+01:00
diff --git a/ymmsl/v0_2/imports.py b/ymmsl/v0_2/imports.py
@@ -105,37 +105,40 @@ def _yatiml_sweeten(self, node: yatiml.Node) -> None:
 
     @classmethod
     def _parse_string_representation(cls, text: str) -> Tuple[str, str, str]:
-        help_text = 'Import statements should look like "from a.b.c import d"'
+        help_text = 'Import statements should look like "from a.b.c import <kind> d"'
 
         parts = text.split()
 
         if len(parts) > 0 and parts[0] != 'from':
             raise RuntimeError(
-                    'Import statement "{text}" does not start with "from".\n' +
+                    f'Import statement "{text}" does not start with "from".\n' +
                     help_text)
 
         if len(parts) > 1:
             module = parts[1]
 
         if len(parts) > 2 and parts[2] != 'import':
             raise RuntimeError(
-                    'Import statement "{text}" does not have "import" part.\n' +
+                    f'Import statement "{text}" does not have "import" part.\n' +
                     help_text)
 
         if len(parts) > 3:
-            try:
-                kind = parts[3]
-            except KeyError:
-                raise RuntimeError(
-                        f'Tried to import an invalid kind of object "{parts[3]}" in' +
-                        f' import statement "{text}".\n' + help_text)
+            kind = parts[3]
+        else:
+            raise RuntimeError(
+                    f'Import statement "{text}" does not specify which kind of thing'
+                    ' to import.\n' + help_text)
 
         if len(parts) > 4:
             name = parts[4]
+        else:
+            raise RuntimeError(
+                    f'Import statement "{text}" does not specify the name of the thing'
+                    ' to import.\n' + help_text)
 
         if len(parts) > 5:
             raise RuntimeError(
-                    'Extra text found at end of import statement "{text}".\n' +
+                    f'Extra text found at end of import statement "{text}".\n' +
                     help_text)
 
         return module, kind, name
diff --git a/ymmsl/v0_2/tests/test_imports.py b/ymmsl/v0_2/tests/test_imports.py
@@ -71,6 +71,16 @@ def test_load_invalid_import6(load_import: LoadImport) -> None:
         load_import('from nlesc.examples[1] import implementation example')
 
 
+def test_load_invalid_import7(load_import: LoadImport) -> None:
+    with pytest.raises(RuntimeError):
+        load_import('from a.b import example')
+
+
+def test_load_invalid_import8(load_import: LoadImport) -> None:
+    with pytest.raises(RuntimeError):
+        load_import('from a.b import implementation')
+
+
 def test_module_path() -> None:
     imp = ImportStatement('nlesc.examples', 'implementation', 'test')
     assert imp.module_path() == Path('nlesc/examples.ymmsl')
