[SR-Dev] git:andrei/type_conversion: news: update (new operators, expr. eval behaviour a.s.o.)

Module: sip-router Branch: andrei/type_conversion Commit: bb4d414574c35b1ba2c0497e19313b4cd000f775 URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=bb4d414… Author: Andrei Pelinescu-Onciul <andrei(a)iptel.org> Committer: Andrei Pelinescu-Onciul <andrei(a)iptel.org> Date: Tue Apr 28 19:54:03 2009 +0200 news: update (new operators, expr. eval behaviour a.s.o.) --- NEWS | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) diff --git a/NEWS b/NEWS index fade123..ed1ab96 100644 --- a/NEWS +++ b/NEWS @@ -6,6 +6,33 @@ $Id$ sip-router changes core: + - new operators eq, ne for string compares and ieq, ine for interger + compares. The names are not yet final (use them at your own risk). + Future version might use ==/!= only for ints (ieq/ine) and eq/ne for + strings (under debate). + They are almost equivalent to == or !=, but they force the conversion + of their operands (eq to string and ieq to int), allowing among other + things better type checking on startup and more optimizations. + Non equiv. examples: 0 == "" (true) is not equivalent to 0 eq "" + (false: it evaluates to "0" eq ""). "a" ieq "b" (true: (int)"a" is 0 + and (int)"b" is 0) is not equivalent to "a" == "b" (false). + Note: internally == and != are converted on startup to eq/ne/ieq/ine + whenever possible (both operand types can be safely determined at + start time and they are the same). + - try to guess what the user wanted when operators that support multiple + types are used on different typed operands. In general convert the + the right operand to the type of the left operand and then perform the + operation. Exception: the left operand is undef. + This applies to the following operators: +, == and !=. + Special case: undef as left operand: + For +: undef + expr -> undef is converted to string => "" + expr. + For == and !=: undef == expr -> undef is converted to type_of expr. + If expr is undef, then undef == undef is true (internally is converted + to string). + - expression evaluation changes: auto-convert to interger or string + in function of the operators: + int(undef)==0, int("")==0, int("123")==123, int("abc")==0 + str(undef)=="", str(123)=="123". - new script operators: defined, strlen, strempty defined expr - returns true if expr is defined, and false if not. Note: only a standalone avp or pvar can be