prolog-clause-start
prolog-clause-start is a compiled Lisp function in `prolog.el
'.
(prolog-clause-start &optional NOT-ALLOW-METHODS)
Return the position at the start of the head of the current clause.
If NOTALLOWMETHODS is non-nil then do not match on methods in
objects (relevant only if `prolog-system' is set to `sicstus').