Re: [Vala] automatic basic type conversions

[Hans Vercammen <hveso3 gmail com>]

On Tue, 2009-01-27 at 12:12 +0100, pancake wrote:
> Actually Vala forces you to pass the correct type for assignations , 
> argument passing in functions, etc..
>
> I think this should be a warning instead of an error. And Vala should 
> know about which basic
> types can be automatically casted (and show a warning) or an error if 
> they cannot be converted.
>
> For example.
>
> If I have a string and i need a uint8* the cast is possible.
>
> Other basic type conversions that are interesting are between types with 
> precission loss:
>
>   double -> float
>   int -> char
>   int -> uint32
>   ...
>
> In the api bindings i'm writing i use uint32 values for length arguments 
> and i have to cast them
> all the time because vala is unable to convert from long to uint32.
>
> I understand that vala should provide a minimal code for making this 
> conversion before calling the
> function, because a negative value should be handled in a different way 
> (like only pass possitive
> value, or so..)
>
> What do you think we should do for this kind of conversions?

In my opinion, I think that any conversion that could be done implicitly
without warning should be allowed, otherwise it should be explicit (so
an error). As far as I know this should already be possible for implicit
conversions where there is no conflict.
However, I think it would be nice to have some kind of warning levels in
vala that could be turned on/off when requested. Something in the sense
of -Werror, -Wall, -Wshadow etc. Maybe it's possible to combine these
things for your case.
I have had some bad experiences in the past with ignoring these kind of
warnings, where I thought ok well; the situation would never occur.
Depending on your compiler optimization and platform, this could cause
nasty runtime errors :) Compilers are probably better these days,
however using -Werror can still save you a lot of trouble.

Regards,
Hans