INVOKE template input
(INVOKE template input1 input2 ...)

Runs the template, filling its slots with the remaining input(s). The number of inputs must be an acceptable number of slots for template. It is illegal to use the primitive TO as a template, but anything else is okay. INVOKE outputs what template outputs, if anything.

INVOKE is similar to APPLY except that INVOKE's inputs are provided as separate expressions rather than in a list.

SHOW (INVOKE "SUM 1 2 3)
6