This type testing predicate succeeds if it's argument is an integer value.
see also: atom/1 atomic/1 compound/1 float/1 nonvar/1 number/1 var/1
| Examples | |
| integer("hello"). | fails |
| integer(-10.1) | fails |
| integer(9). | succeeds |
| integer([a]). | fails |
| X=12, integer(X). | succeeds |