Defines a instruction with a closure.
Since it is rather bothersome to keep repeating code over and over, it'd be nice to be able define instructions as composites of other for the scope of the program.
DEF allows to define instruction's program for the scope of the script's
DEF will put the second topmost item off the stack (
c) into the
instruction referenced by top item (
PumpkinDB> [DUP DUP] 'dup2 DEF 1 dup2 1 1 1
EmptyStack error if there are less than two items on the stack.
It will error if the format of the instruction is incorrect
It may error if this instruction is a built-in instruction that was previously defined.
works : [DUP DUP] 'dup2 DEF 1 dup2 3 WRAP 1 1 1 3 WRAP EQUAL?. empty_stack : [DEF] TRY UNWRAP 0x04 EQUAL?. empty_stack_1 : ['a DEF] TRY UNWRAP 0x04 EQUAL?.