asterisk users - Mar 2016 - Dialplan question: Variables in GoTo() ?

I can't seem to find a definitive answer on this, and I really don't
want to
risk breaking a production server to find out; so I am going to try asking this 
here, and maybe anyone else in the same situation searching the archives 
sometime in future will find the answer I get.

Can you use variables in the target of a GoTo() statement?

What I am specifically thinking of is this;

[from_some_source]
exten => s,1,AGI(look_up_stuff.agi,${CALLERID(num)},${EXTEN})
; this AGI script sets variables: next_context, next_ext, next_step
exten => s,n,GoTo(${next_context},${next_ext},${next_step})

Will this work?  Does Asterisk evaluate expressions like this, or does it 
expect literals?


-- 
AJS

Note:  Originating address only accepts e-mail from list!  If replying off-
list, change address to asterisk1list at earthshod dot co dot uk .

On Thu, 10 Mar 2016, A J Stiles wrote:
> Can you use variables in the target of a GoTo() statement?
Yes. Here are a few examples from one of my dialplans:

; invalid template
[i](!)
         exten = i,1,                    verbose(1,[${EXTEN}@${CONTEXT}])
         exten = i,n,                    goto(${CONTEXT},s,1)

; look up (set) DNIS (DID) channel variables
         exten = _x.,n,                  goto(lookup-dnis,${EXTEN},1)

; dispatch to selected application
         exten = _[123456],n,           
goto(${PRODUCT-${EXTEN}-APPLICATION},s,1)

This particular dialplan uses the invalid template in around 30 contexts 
and 'goto(${CONTEXT},s,1)' about 15 times. Note that the last example 
'nests' the variable expansion -- a variable within a variable.

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST

A J Stiles wrote:
> I can't seem to find a definitive answer on this, and I really
don't want to
> risk breaking a production server to find out; so I am going to try asking
this
> here, and maybe anyone else in the same situation searching the archives
> sometime in future will find the answer I get.
>
> Can you use variables in the target of a GoTo() statement?
>
> What I am specifically thinking of is this;
>
> [from_some_source]
> exten =>  s,1,AGI(look_up_stuff.agi,${CALLERID(num)},${EXTEN})
> ; this AGI script sets variables: next_context, next_ext, next_step
> exten =>  s,n,GoTo(${next_context},${next_ext},${next_step})
>
> Will this work?  Does Asterisk evaluate expressions like this, or does it
> expect literals?
It most certainly will work. It evaluates on use.

-- 
Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

On Thursday 10 Mar 2016, Joshua Colp wrote:
> I wrote:
> > I can't seem to find a definitive answer on this, and I really
don't want
> > to risk breaking a production server to find out; so I am going to try
> > asking this here, and maybe anyone else in the same situation
searching
> > the archives sometime in future will find the answer I get.
> > 
> > Can you use variables in the target of a GoTo() statement?
> > 
> > What I am specifically thinking of is this;
> > 
> > [from_some_source]
> > exten =>  s,1,AGI(look_up_stuff.agi,${CALLERID(num)},${EXTEN})
> > ; this AGI script sets variables: next_context, next_ext, next_step
> > exten =>  s,n,GoTo(${next_context},${next_ext},${next_step})
> > 
> > Will this work?  Does Asterisk evaluate expressions like this, or does
it
> > expect literals?
> 
> It most certainly will work. It evaluates on use.
Thanks very much.  I tried it, and it worked beautifully.  Exactly as I 
expected.  

There is something a little bit "ZX Spectrum BASIC" about an evaluated
GOTO,
but sometimes it's the least messy way of accomplishing something.

-- 
AJS

Note:  Originating address only accepts e-mail from list!  If replying off-
list, change address to asterisk1list at earthshod dot co dot uk .