Select Active / Switch Case

ryanww · November 2007

So in either Select Active or Switch Case, can multiple instances happen? I would guess more so with Select Active..

Here is an example:

X=1, Y=1, Z=0
SELECT
{
ACTIVE (X):
{DO SOMETHING}
ACTIVE (Y):
{DO SOMETHING ELSE}
ACTIVE (Z):
{DO SOMETHING ELSE}
}

Would both the commands in X and Y execute assuming both statments were true?

Thanks

shr00m-dew · November 2007

Each ACTIVE statement could be looking different variables, so each one could be true. Each one that is will execute. On a SWITCH/CASE, you are only looking at one variable. Only one (or none) of the case's can be true at the same time.

Kevin D.

ryanww · November 2007

Cool, thats what I thought.. Just wanted to make sure..

Thanks

AM93 · November 2007

No. In Amxland there is no fall-thru only the first true condition is executed the rest are ignored.

So for easy examples you could do:

Select
{
Active ((X) || (Y) || (Z)): Do Stuff if you want the same result
}

OR

If (X) Do thing #1
If (Y) Do thing #2
If (Z) Do thing #3

ryanww · November 2007

Aw.. that sucks.. Well that would be a cool command for the future of AMX.. It would come in handy for me a few times.. Just a few less things to do..

shr00m-dew · November 2007

I stand corrected. Never had a need for the first example but always assumed based on the wording. I almost ran a test program because I wasn't 100%.. Damn.

Kevin D.

shr00m-dew · November 2007

Man, it's right there in the help file too..

The SELECT?ACTIVE statement provides a programming structure for selective execution of code blocks based on the evaluation of a series of conditions. The first block whose ACTIVE condition evaluates to true is executed; the remaining blocks are ignored. If no ACTIVE condition evaluates to true, no statements are executed.

Kevin D

ericmedley · November 2007

X=1, Y=1, Z=0
IF(X)
{DO SOMETHING}
IF(Y)
{DO SOMETHING ELSE}
IF(Z)
{DO SOMETHING ELSE}

This will allow more than one state to fire in the same statement

mpullin · November 2007

switch...case

It should also be noted switch...case in Netlinx has a subtle difference compared to every other language that structure appears.

switch(nVar){
   case 1: SEND_COMMAND dvDev, 'A'; break;
   case 2:
   case 3:
   case 4:
   case 5: SEND_COMMAND dvDev, 'B'; break;
   case 6: SEND_COMMAND dvDev, 'C';
   default: SEND_COMMAND dvDev, 'D'; break;
}

nVar=1 only triggers A. nVar=2, 3, 4, or 5 will all trigger B. However, you would expect (if you came from other languages) that nVar=6 would trigger C and D, but no, it only triggers C.

The case only falls through in the case of a totally empty case. The break keyword in a switch...case is merely cosmetic in this langauge.

ryanww · November 2007

Well I am looking to do the opposite of that.. well kind of.. I just want one Select Active set but if say like multiple variables are true, it will fire those, but not necessarily together..

Daniel Tehan · November 2007

mpullin wrote:

... nVar=2, 3, 4, or 5 will all trigger B....

Alternatively if you want nVar=2 to do nothing you need to add curly brackets to the code:

case 2: {}

Select Active / Switch Case

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