Python: Add support for snake case imports (#6229)

When using slint.loader.app_window.XXX look for "app_window.slint" followed by "app-window.slint".

Fixes #6216

api/python/README.md

@@ -129,7 +129,8 @@ options:
    Any attribute lookup in `slint.loader` is searched for in `sys.path`. If a directory with the name exists, it is returned as a loader object, and subsequent
    attribute lookups follow the same logic. If the name matches a file with the `.slint` extension, it is automatically loaded with `load_file` and the
    [namespace](https://docs.python.org/3/library/types.html#types.SimpleNamespace) is returned, which contains classes for each exported component that
-   inherits `Window`.
+   inherits `Window`. If the file name contains a dash, like `app-window.slint`, an attribute lookup for `app_window` will
+   first try to locate `app_window.slint` and then fall back to `app-window.slint`.
 
 ### Accessing Properties
 

api/python/slint/__init__.py

@@ -275,6 +275,13 @@ class SlintAutoLoader:
                 setattr(self, name, type_namespace)
                 return type_namespace
 
+            dir_candidate = os.path.join(path, name.replace('_', '-'))
+            file_candidate = dir_candidate + ".slint"
+            if os.path.isfile(file_candidate):
+                type_namespace = load_file(file_candidate)
+                setattr(self, name, type_namespace)
+                return type_namespace
+
         return None
 
 

api/python/tests/test_callback_decorators.py

@@ -8,7 +8,7 @@ import os
 
 def test_callback_decorators(caplog):
     module = load_file(os.path.join(os.path.dirname(
-        __spec__.origin), "test_load_file.slint"), quiet=False)
+        __spec__.origin), "test-load-file.slint"), quiet=False)
 
     class SubClass(module.App):
         @slint.callback()

api/python/tests/test_load_file.py

@@ -8,7 +8,7 @@ import os
 
 def test_load_file(caplog):
     module = load_file(os.path.join(os.path.dirname(
-        __spec__.origin), "test_load_file.slint"), quiet=False)
+        __spec__.origin), "test-load-file.slint"), quiet=False)
 
     assert "The property 'color' has been deprecated. Please use 'background' instead" in caplog.text
 
@@ -42,7 +42,7 @@ def test_load_file_fail():
 
 def test_load_file_wrapper():
     module = load_file(os.path.join(os.path.dirname(
-        __spec__.origin), "test_load_file.slint"), quiet=False)
+        __spec__.origin), "test-load-file.slint"), quiet=False)
 
     instance = module.App()
 
@@ -66,7 +66,7 @@ def test_load_file_wrapper():
 
 def test_constructor_kwargs():
     module = load_file(os.path.join(os.path.dirname(
-        __spec__.origin), "test_load_file.slint"), quiet=False)
+        __spec__.origin), "test-load-file.slint"), quiet=False)
 
     def early_say_hello(arg):
         return "early:" + arg