[SR-Dev] operators and variables

[Andrei Pelinescu-Onciul]

On Dec 12, 2008 at 16:41, Jan Janak <jan at ryngle.com> wrote:
> On 11-12 22:01, Andrei Pelinescu-Onciul wrote:
> > 
> > It would be better to have different operators for strings and for
> > integers. Right now we have '+', '==' and '!=' that can be used both for
> > strings and integers. The problem with this approach is that it makes
> > some optimizations impossible, especially when combined with dynamic
> > typed variables (avps or pvars). '+' is especially bad because one
> > can tell what type ($v + x) has only at runtime.
> 
>   I would like to preserve the original behaviour for strings. They are used
>   much more often than integers. If you need to change anything then, please,
>   consider changing the behaviour of integer operators.
> 
> > I think having perl like operators would help a lot:
> > 
> > - '.' for string concatenation (instead of reusing '+'), e.g.: 
> >  $v= "foo" .  "bar"
> 
>   Yes, I like this one.
> 
> > - 'eq' instead of == for strings, e.g.: $v eq "bar" 
> > - 'ne' instead of != for strings, e.g.: $v ne "bar"
> 
>   I don't like this. If there really is a need to have separate operators then
>   use 'eq' and 'ne' for integers and keep == and != for strings. Test (see man
>   test) has string and integer operators this way.

I was using perl as a guideline (since we already have perl like stuff,
like ~=).

> 
> > We could support them right now in parallel with the old ones and 
> >  obsolete +, ==  and != for strings in the future (but that means we
> >  still cannot optimize '+' in all the cases) or switch right now
> > (maybe with some old compat switch which will support old scripts
> > style).
> > The question is how much are they used right now. While I think '==' and
> > '!=' are used quite often, I'm not sure about '+' for strings (and '+'
> > is the most important anyway).
> 
>   I guess == and != are used most often with strings.
> 
> > Note: we can still support '==' and '!='  for condition tests not
> > involving variables (e.g. method=="INVITE", uri=="sip:foo" a.s.o.).
> 
>   That would be inconsistent. if (method=="INVITE") would work, but
>   if ($abc=="foo") would not work if strings operators are replaced with 'eq'
>   and 'ne'.

Yes, it would be, but I was thinking that most people use it only this
way and hence the change would not affect them immediately.


Andrei