Re: [Vala] Help me find the right Vala idiom

[Andrea Del Signore <sejerpz tin it>]

On Tue, 2012-03-06 at 10:44 +0000, Chris Elston wrote:
> Thanks to both Mark and Andrea for taking the time to look at this for
> me.

YW

> Mark's solution is good because it looks to me like pretty clean OO
> without using GObject introspection. I'm not sure on the cost of

I was sure that someone would suggest an OO oriented solution like Mark
did, so I came up with a different approach :)

> wrapping each fundamental type in a parse class though. How much memory
> does each of those wrapping class instances take up when my config class
> might have hundreds of them?

Few KB? And you can instantiate these classes only during the parsing of
the config and release the memory after that.

> I like Andreas solution too, particularly because it separates the
> business of parsing the data from the target class to be instantiated
> with the data. It also seems like it would scale better because the
> fundamental types in ConfigData aren't wrapped in another class.

Yes, but I bet that my code is worse performance wise. Take in mind that
when I search and assign a property I do 2 lookups in the object
property table.
As I said I traded performance and flexibility for a minimal and easy to
use API. (For example a config class must define all the options as
properties and not simple fields, it must derive from GObject etc...)

> Some quick profiling shows that Andrea's solution gives a binary about
> 2.5 times bigger and about half as fast as the C (for 100 iterations).
> Although Andrea's solution is also doing more error checking than my
> quick and dirty example. Is this fairly typical of Vala code. Can anyone
> comment on how much of that is down to Vala and how much is down to
> GObject? i.e.: if I were to write equivalent GObject C, would I get
> similar performance and size to the compiled Vala code?

IMHO: 
vala GObject code is more or less like C GObject code performance wise
but not size wise (I GObject-C you can decide the amount of checking,
copying you'll do/write, with vala all this code is always generated
even if not required).
On the other side I think that GCC optimizations will catch and solve
most of these problems.

> Cheers,
>
> Chris.

Ciao,
Andrea

P.S.
Because this was just and example, to read the file I used an IOChannel,
today "the cool guys" will use GIO instead ;)