[asterisk-users] Reasons to use AEL (was: Re: Goto from a feature macro is not working?)

[Philipp Kempgen]

Miguel Molina schrieb:
> Philipp Kempgen escribió:

>> Use macros in AEL so you don't have to care about the underlying
>> implementation. :-) scnr

> Right now for every implementation I made, I didn't have the need to 
> program in AEL, only plain extensions, some AMI and AGI. But well, it 
> seems to have a lot of advantages. Please tell me some, I may take a 
> look to it too see if it's worth spending the time to learn and get the 
> best out of it.

I'd say control structures (and proper indentation) are one of the
most important reasons to use AEL (conditionals: if .. else, switch
.. case, ..., loops: for, while) because they look so familiar.
Imagine nested "control structures" in extensions.conf with Goto(),
GotoIf(), While(), EndWhile(), ExitWhile(), ContinueWhile() and
priorities - such code is not what I call maintainable.

== extensions.conf:

exten => 30,1,Set(x=5)
exten => 30,n,While($[${x} <= 9])
exten => 30,n,NoOp(x ist ${x})
exten => 30,n,ExecIf($[${x} > 5],ExitWhile)
exten => 30,n,Playback(beep)
exten => 30,n,Set(x=$[${x} + 1])
exten => 30,n,EndWhile()
exten => 30,n,NoOp(done)

== extensions.ael:

30 => {
    x=0;
    while (${x} <= 9) {
        NoOp(x ist ${x});
        if (${x} > 5) {
            break;
        }
        Playback(beep);
        y=${x} + 1;
    }
    NoOp(done);
}

In this example, we needed more lines in AEL; if we had added another
command to the if condition in our while loop, ExecIf() would not be
enough anymore and we would be forced to use a more complex construc-
tion with GotoIf(). Our extensions.conf would be a lot longer.


    Philipp Kempgen
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