chickadee » forcible » force

force OBJECT #!optional FAILprocedure

Force OBJECT. Returns OBJECT if it is NOT a promise. Otherwise returns the values the suspended EXPRESSION returned.

If FAIL is provided it must be a procedure of one argument. Exceptions raised from the EXPRESSION are passed to FAIL.

This is equivalent to (but more efficiently implemented)

(handle-exceptions ex (FAIL ex) (force OBJECT))