AEL Switch & Case

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Hi.

I think I’ve discovered a bug in either the implementation of the documentation of the AEL switch command.

https://wiki.asterisk.org/wiki/display/AST/AEL+Conditionals gives an example of using switch, and states at the bottom:

“Neither the switch nor case values are wrapped in $[ ]; they can be constants, or ${var} type references only.”

However, I’ve run into a problem, which can be demonstrated by the simple context:

context SwitchTest {
s => {
Set(FortyTwo=42);
Set(SixByNine=54);
switch(${SixByNine}) {
case 123:
NoOp(123);
break;
case ${FortyTwo}:
NoOp(${FortyTwo});
break;
}
}
}

This gets converted by AEL into:

[ Context ‘SwitchTest’ created by ‘pbx_ael’ ]
‘s’ => 1. MSet(~~EXTEN~~=${EXTEN})
2. Set(FortyTwo=42)
3. Set(SixByNine=54)
4. Goto(sw_5410_${SixByNine},10)
5. NoOp(Finish switch_SwitchTest_5410)
‘sw_5410_’ => 10. Goto(sw_5410_.,10)
11. Goto(s,5)
‘sw_5410_123’ => 10. NoOp(123)
11. Goto(s,5)
‘_sw_5410_.’ => 10. Goto(s,5)

So, there was no implementation of the “case ${FortyTwo}” match.

Am I misundertanding “they can be constants, or ${var} type references only.”?

Antony.

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2 thoughts on - AEL Switch & Case

  • I don’t think this is a bug. ${FortyTwo} is not defined when the AEL
    dialplan is transpiled into dialplan. It only gets set at runtime. This might work if you made FortyTwo a global variable, which would be available when this gets parsed.

    NA

    —

  • Replying to list this time…

    Agreed, however that is surely a perfectly reasonable “${var} type reference”?

    Quite possibly, but I would expect switch() to work in the same way as multiple if() statements:

    switch(${a}) {
    case ${b}: NoOp(${b} matches); break;
    case ${c}: NoOp(${c} matches); break;
    // etc….
    }

    should be equivalent to:

    if(${a}=${b}) NoOp(${b} matches);
    if(${a}=${c}) NoOp(${c} matches);
    // etc….

    The latter works perfectly well, no matter when ${b} and ${c} are assigned their values.

    I’ve adjusted my dialplan to use multiple if()s, but I still thik that either the implementation or the documentation of switch is incorrect.

    Antony.

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