17 Aug 2005 18:09

ADP

I love Asterisk. It is a superb piece of software and a fine example of open source success. However, the extensions.conf syntax is painful at best. I haven't had to worry about linenumbers since my GW-BASIC days, and even then it wasn't necessary that line be numbered sequentially. So I did some thinking about how to solve this problem, and decided the best approach would be to write a translator that takes something sane, which I will call ADP, and translate it to standard extensions.conf format. Let's look at an example. Instead of this:

[incoming]
exten => s,1,Wait(1)
exten => s,2,Answer
exten => s,3,Playback(greeting)
exten => s,4,VoiceMail(77&80)
exten => s,5,Hangup

we write this:

[incoming]
ext s {
    Wait(1)
    Answer
    Playback(greeting)
    VoiceMail(77&80)
    Hangup
}

Now, adding Zapateller between Answer and Playback does not require manually reordering priority numbers.

I decided on the language and wrote a grammar for it, then dusted off my lex/yacc skills (and book) and wrote me a C implementation of ADP. You can find the current version and darcs repository at http://hans.fugal.net/src/adp. It works, but there are probably bugs and certainly memory leaks (but unless you have a gargantuan extensions.conf, who cares?)

I hope you find it useful. Suggestions and patches welcome.

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