LIKE, REGEXP, and GLOB are also functions and "language elements".
That is, `select * from somewhere where a like 'twat%' escape '\';` is equivalent to `select * from somewhere where like('twat%', a, '\');`. The same also applies to the GLOB and REGEXP keywords, which are also functions.
While `current_time`, `current_date`, and `current_timestamp` are "language elements", the use of those names as functions is not implemented.