Re: Is there any useful place where OP

Quote from: RobinLinus on February 12, 2022, 11:03:31 AM

Here is an example how you could use it in an interesting way: https://github.com/coins/bitcoin-scripts/blob/master/op-codeseparator.md

I think I saw this 2 months ago when I started the topic and it still doesn't make any sense. Take the last example:

Code:

OP_IF
# Case 1
OP_CODESEPARATOR
600300
OP_ENDIF

OP_IF
# Case 2
OP_CODESEPARATOR
600200
OP_ENDIF

OP_IF
# Case 3
OP_CODESEPARATOR
600100
OP_ENDIF

OP_CHECKLOCKTIMEVERIFY
OP_DROP

2
<Alice.Pubkey>
<Bob.Pubkey>
2
OP_CHECKMULTISIG

When you spend it with something like

Code:

<Bob.SignatureCase1>
<Alice.SignatureCase1>
0 0 1

The first IF pops 1 but the second IF is not popping the 0, instead it pops 600300 that was pushed to the stack inside the conditional branch! And OP_CODESEPARATOR doesn't seem to be doing anything here. Then 600200 will be pushed to the stack to be popped by the next IF and finally 600100 which will be popped by OP_CHECKLOCKTIMEVERIFY.
So why not use a nested IF?

Code:

OP_IF
600300
OP_ELSE
OP_IF
600200
OP_ELSE
600100
OP_ENDIF
OP_ENDIF

OP_CHECKLOCKTIMEVERIFY
OP_DROP

2
<Alice.Pubkey>
<Bob.Pubkey>
2
OP_CHECKMULTISIG

It is shorter and achieves the same thing without OP_CODESEPARATOR.