Merge branch 'develop'HEADv0.23.03releasemain

1 files changed, 49 insertions, 0 deletions

diff --git a/bsie/utils/loading.py b/bsie/utils/loading.py
new file mode 100644
index 0000000..58202d1
--- /dev/null
+++ b/bsie/utils/loading.py
@@ -0,0 +1,49 @@
+
+# standard imports
+import importlib
+import typing
+
+# inner-module imports
+from . import errors
+
+# exports
+__all__: typing.Sequence[str] = (
+    'safe_load',
+    'unpack_qualified_name',
+    )
+
+
+## code ##
+
+def safe_load(module_name: str, class_name: str):
+    """Get a class from a module. Raise BuilderError if anything goes wrong."""
+    try:
+        # load the module
+        module = importlib.import_module(module_name)
+    except Exception as err:
+        # cannot import module
+        raise errors.LoaderError(f'cannot load module {module_name} ({err})') from err
+
+    try:
+        # get the class from the module
+        cls = getattr(module, class_name)
+    except Exception as err:
+        # cannot find the class
+        raise errors.LoaderError(f'cannot load class {class_name} from module {module_name} ({err})') from err
+
+    return cls
+
+
+def unpack_qualified_name(name):
+    """Split a name into its module and class component (dot-separated)."""
+    if not isinstance(name, str):
+        raise TypeError(name)
+    if '.' not in name:
+        raise ValueError('name must be a qualified class name.')
+    module_name, class_name = name[:name.rfind('.')], name[name.rfind('.')+1:]
+    if module_name == '':
+        raise ValueError('name must be a qualified class name.')
+    return module_name, class_name
+
+
+## EOF ##