unifies the number of the characters of an atom.
atom_length/2 unifies Number with the number of characters of Atom.
Atom atom Number integer >= 0
| atom_length('this is quite a long text', N). | Succeeds with substitution N <- 25 |
| atom_length('four', 4). | Succeeds. |
| atom_length('five', 5). | Fails. |
This predicate is part of the ISO-Prolog Standard.