Gnucash c++

[John Ralls]

On Aug 13, 2014, at 3:42 PM, Gour <gour at atmarama.net> wrote:

> On Wed, 13 Aug 2014 11:21:59 -0400
> Derek Atkins <warlord at MIT.EDU> wrote:
> 
>> Ummm.. No.
> 
> OK.
> 
>> The benefit of C -> C++ is that except for a few minor issues with
>> keywords you can *generally* compile C code using the C++ compiler and
>> it will *just work*.  
> 
> That's clear.
> 
>> The same cannot be said for Go or any other language.
> 
> Btw, Go team converts Go compiler from C to Go. ;)
> 
>> Please read the FAQ entry on "Why don't you (re)write GnuCash in <your
>> favorite language>" at http://wiki.gnucash.org/wiki/FAQ
> 
> Well, being in #gnucash I got the feeling that there is plan to abandon
> glib, rewrite the engine and possibly even to consider Qt 'cause
> without glib, one is not tied so much to GTK any longer.
> 
> Considering that C --> C++ (and taking advantage of it) might be more
> strange than C --> Go which is created to be picked easily by C devs, I
> did throw my suggestion.
> 
> Otoh, I believe that C --> C++ is not to be done in order to just
> increase build time.* :-) 
> 
> * Rob Bike from the Go team says that long build times (~45mins) for C++
> * projects was the time when Go was conceived. ;)
> 
> I'm aware of FAQ entry, but was thinking that GC is on the verge of
> possible (partial) rewrite.

All true, but you missed Derek's point. The advantage of C++ is that one can use it with C *in the same file*. That means I can take a C file, tell the compiler it's really a C++ file, and compile it almost as-is (that's what Aaron's change is about, cleaning up all of the almosts). Then I can make a C++ class and move the functionality into it one function at a time, converting the C function to a wrapper with C linkage. I can test that against the existing C tests, add C++ tests, and move on to the next function. The rest of GnuCash can't tell anything's changed; new work now has two versions of the API to use depending on whether it's completely new or a modification of existing. If it comes time to start the release cycle and the conversion isn't complete, we can ship it as-is because nothing's broken.

There other languages like that, but they're all AFAIK tied to particular proprietary platforms to some extent: Objective C and Apple, C# and Microsoft, Vala and Gtk+. C++ is ISO-standard with an extremely active committee.

Regards,
John Ralls