SWAP
Swaps the order of the two topmost items on the stack
Input stack: a b
Output stack: b a
PumpkinScript> 0x10 0x20 SWAP
0x20 0x10
Allocation
None
Errors
EmptyStack error if there are less than two items on the stack
Tests
works : 1 2 SWAP.
empty_stack : [SWAP] TRY UNWRAP 0x04 EQUAL?.
empty_stack_1 : [1 SWAP] TRY UNWRAP 0x04 EQUAL?.