call/1: checks (via it.unibo.tuprolog.solve.stdlib.primitive.EnsureExecutable) that its argument is a callable term, then resolves it as a goal -- equivalent to call(G) :- ensure_executable(G), G..
call/1
it.unibo.tuprolog.solve.stdlib.primitive.EnsureExecutable
call(G) :- ensure_executable(G), G.