expander will call @var{expander} with that form as well as with
@var{args}@dots{}, and @var{expander} can either return a new expression to use
instead of the function call, or it can return just the form unchanged,
-to indicate that the function call should be left alone. @var{expander} can
-be a symbol, or it can be a form @code{(lambda (@var{arg}) @var{body})} in
-which case @var{arg} will hold the original function call expression, and the
-(unevaluated) arguments to the function can be accessed using the function's
-formal arguments.
+to indicate that the function call should be left alone.
+
+When @var{expander} is a lambda form it should be of the form
+@code{(lambda (@var{arg}) @var{body})} because the function's formal
+arguments are automatically added to the lambda's list of arguments.
@item (gv-expander @var{expander})
Declare @var{expander} to be the function to handle calls to the macro (or