if vs elseif statements

[sethmachine]

Hi,

What is more computationally expensive for WC3? Evaluating a string of if statements, or a string of a single if followed by elseif statements?

Suppose that the truth values of A, B, C are not related, but simply possible values that need to each have a check. In the case where A,B,C are not independent, then of course it makes sense to use elseif. But I am not referring to that case, therefore don't bring it up

if A then
endif
if B then
endif
if C then
endif

if A then
elseif B then
elseif C then
endif

 

[chobibo]

won't compile	will compile
if A then endif elseif B then endif elseif C then endif	if A then elseif B then elseif C then endif

 

[sethmachine]

Yes I fixed it, but the problem wasn't a syntax error. It's a question of performance.

 

[Vinz]

lol chobibo, he was asking which is easier for the engine to do.

 

[chobibo]

^ I know what he is asking, I just didn't know the answer. Why don't you dump the bytecode for us so we can at least make an educated guess?

Anyway, if that piece of code wasn't compiled then clearly it will be faster because wc3's engine will refuse to execute it, but that kind of answer is sarcastic.

EDIT:
I think IcemanBo's answer is the right one.

 

[IcemanBo]

A, B, C should be completly independant and not related to each other? Why it should make sense to use elseif in such a case?

If you want avoid further checks because one solution has been found already, then use elseif, obviously.
Else not. (muhaha)

 

[deathismyfriend]

if A then
endif
if B then
endif
if C then
endif

The above is more computationally expensive for WC3 because it adds extra steps by stopping the if block then starting a new one.

if A then
elseif B then
elseif C then
endif

 

[Rui]

What the post above me said.

The two blocks you referred are not equivalent (unless A, B and C are logically connected somehow). In elseifs, if A is true then it won't even check B or C.

 

[sethmachine]

Alright to put things in perspective I'm checking a series of button presses. I've been using if + elseif blocks, but I want to just use if…endif blocks for each button check so I can use a text macro to significantly reduce the number of lines from the programmer's point of view in order to ease editing. (yes I know it actually doesn't reduce the number of lines in the final compiled script).

I'm re-thinking now and I suppose I can use the type of block header as a parameter for the text macro.

 

[WaterKnight]

Or you could avoid an if mess altogether and assign the data/the code to run to each button.

In wurst there should be the switch instruction.