prolog-types

prolog-types is a variable defined in `prolog.el'.
Its value is

((mercury
  ("char" "float" "int" "io__state" "string" "univ"))
 (t nil))

Documentation:
Alist of Prolog types used by font locking.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.1 of Emacs.