Merge pull request #161 from pyiron/resolve

[refactor] Separate transformation to object from ast parsing

Author: samwaseda

flowrep/models/parsers/object_scope.py

@@ -24,28 +24,57 @@ def get_scope(func: FunctionType) -> ScopeProxy:
     return ScopeProxy(inspect.getmodule(func).__dict__ | vars(builtins))
 
 
+def resolve_attribute_to_object(attribute: str, scope: ScopeProxy | object) -> object:
+    """
+    Resolve a dot-separated attribute string to the actual object it references in the
+    given scope. For example, if attribute is "os.path.join", this function will
+    return the actual join function from the os.path module.
+
+    Args:
+        attribute: A dot-separated string representing the attribute to resolve.
+        scope: The scope in which to resolve the attribute. This can be a ScopeProxy
+            or any object that supports attribute access.
+
+    Returns:
+        The object that the attribute resolves to in the given scope.
+    """
+    obj = None
+    try:
+        for attr in attribute.split("."):
+            obj = getattr(obj or scope, attr)
+        return obj
+    except AttributeError as e:
+        raise ValueError(f"Could not find attribute '{attr}' of {attribute}") from e
+
+
 def resolve_symbol_to_object(
     node: ast.expr,  # Expecting a Name or Attribute here, and will otherwise TypeError
     scope: ScopeProxy | object,
     _chain: list[str] | None = None,
 ) -> object:
-    """ """
+    """
+    Recursively resolve a symbol in the form of an ast.Name or ast.Attribute to the
+    actual object it references in the given scope. The _chain parameter is used
+    internally to keep track of the attribute chain being resolved, and should not
+    be provided by the caller.
+
+    Args:
+        node: An ast.expr representing the symbol to resolve. Expected to be an
+            ast.Name or ast.Attribute.
+        scope: The scope in which to resolve the symbol. This can be a ScopeProxy
+            or any object that supports attribute access.
+
+    Returns:
+        The object that the symbol resolves to in the given scope.
+    """
     _chain = _chain or []
-    error_suffix = f" while attempting to resolve the symbol chain '{'.'.join(_chain)}'"
     if isinstance(node, ast.Name):
-        attr = node.id
-        try:
-            obj = getattr(scope, attr)
-            for attr in _chain:
-                obj = getattr(obj, attr)
-            return obj
-        except AttributeError as e:
-            raise ValueError(f"Could not find attribute '{attr}' {error_suffix}") from e
+        return resolve_attribute_to_object(".".join([node.id] + _chain), scope)
     elif isinstance(node, ast.Attribute):
         return resolve_symbol_to_object(node.value, scope, [node.attr] + _chain)
     else:
         raise TypeError(
-            f"Cannot resolve symbol {node} {error_suffix}. "
-            f"Expected an ast.Name or chain of ast.Attribute and ast.Name, but got "
-            f"{node}."
+            f"Cannot resolve symbol {node} while building the symbol chain "
+            f"'{'.'.join(_chain)}'. Expected an ast.Name or chain of ast.Attribute "
+            f"and ast.Name, but got {node}."
         )

tests/unit/models/parsers/test_object_scope.py

@@ -74,3 +74,12 @@ def test_unrecognized_node_raises(self):
         node = ast.Constant(value=42)
         with self.assertRaises(TypeError):
             object_scope.resolve_symbol_to_object(node, scope)
+
+    def test_resolve_attribute_to_object(self):
+        scope = object_scope.ScopeProxy({"ast": ast})
+        f = object_scope.resolve_attribute_to_object("ast.literal_eval", scope)
+        self.assertIs(f, ast.literal_eval)
+
+
+if __name__ == "__main__":
+    unittest.main()