----------------------------------------------------------------------
is_const                                                        (Term)
----------------------------------------------------------------------
is_const : term -> bool

SYNOPSIS
Tests a term to see if it is a constant.

DESCRIBE
If {c} is an instance of a previously declared HOL constant, then
{is_const c} returns {true}; otherwise the result is {false}.

FAILURE
Never fails.

SEEALSO
Term.mk_const, Term.dest_const, Term.is_var, Term.is_comb,
Term.is_abs.

----------------------------------------------------------------------