[Asterisk-Users] expression parsing

[ml at neoninternet.com]

Hi.  I've noticed a problem with the expression parsing in Asterisk.  If the variable is not defined, I will get a parse error.  Yeah, there are ways around it, but I would think that it should return false if 0, null, or undefined.  I would change it, but I have no idea about bison and I only have very basic C skills.

There was a bug opened on this, and there was a valid work-around posted, but I would think that it would be 'nicer' if it would evaluate it this way.  (Ref: http://bugs.digium.com/bug_view_page.php?bug_id=0000401 )  If you put a 0 after the } it does work as I would want it to without an error.  The other suggestions did not work.  I propose for this bug to be re-opened.

extensions.conf:
exten => 1234,3,GotoIf($[${a}]?4:5) 

If a is undefined:
WARNING[37910]: File ast_expr.y, Line 346 (ast_yyerror): ast_yyerror(): syntax error: parse error
    -- Executing GotoIf("SIP/1240-5eb6", "0?4:5") in new stack
    -- Goto (default,1234,5)

If I change the extention to exten => 1234,3,GotoIf($[${a}0]?4:5) it works as expected.

Also, I'm not sure if this is my bad or what.  If I use exten => 1234,3,GotoIf(${a}?4:5) and a is undefined:

    -- Executing GotoIf("SIP/1240-2b8a", "?4:5") in new stack
    -- Goto (default,1234,4)

it still returns true.

Behold the power of *,

Kevin