[asterisk-users] If would possible use a custom function in Asterisk Dialplan

[Shitian Long]

Hello,

If would be possible to use a "function concept" in side of Asterisk DialPlan 

For example:

I have following logic in my dial plan remove country code a add an "0" before the rest of the numbers 


exten => _X.,1, NoOp( call ID ${CALLERID(num)}  exten: ${EXTEN}))
; remove my country code
exten => _X.,n, GotoIf($["${CALLERID(num):0:4}"="${country-code}"]?international-format:national-format)
exten => _X.,n(international-format), Set(CALLERID(num)=0${CALLERID(num):4}) 
exten => _X.,n(national-format), NoOp(call ID: ${CALLERID(num)} exten: ${EXTEN}))

Do you think if would be possible that I could write a function something like "REMOVEMYCOUNTRYCODE(${NUM})" with a return value of a number with out country code and with an "0" add in front of the rest of the numbers.

like 

exten => _X.,1, NoOp( call ID ${CALLERID(num)}  exten: ${EXTEN}))
; remove my county code
exten => _X.n, Set(CALLERID(num=REMOVEMYCOUNTRYCODE(${CALLERID(num)} )); 

then I have to define this function in someway ……

I am trying to googling for a while but I did not find any idea to achieve this task. 

I would appreciate if someone have an idea…

Thanks for your time in advance.


longst