Arguments:

Object
ToggleObject
If second argument is present, select the object addressed by that idpath, else selects the object under the cursor.
Block Selects all objects in a rectangle indicated by the cursor.
All Selects all objects on the board.
Connection Selects all connections with the ``found'' flag set.
Convert Converts the selected objects to a subcircuit. This uses the highest numbered paste buffer.
Invert Invert selection: anything that was not selected becomes selected, everything that was selected becomes unselected. Locked objects are not affected.