Beyond 2.8 - some design thoughts

[Geert Janssens]

Op maandag 25 december 2017 17:34:22 CET schreef Christian Stimming:
> Hi Geert,
> 
> just two bits of thoughts from my side:
> 
> Am Sonntag, 24. Dezember 2017, 17:34:51 schrieb Geert Janssens:
> > 1. Use of namespaces.
> > ... nested namespaces ...
> 
> Yes, absolutely. I have quite some experience with C++ libraries and
> applications and I made very positive experience with this scheme. In our
> case this means we put all of our code in a "gnc::" namespace (at least).
> 
> For me, the nicest way to write this was indeed to wrap the content of every
> file by "namespace gnc {" and "}" (except for the #include directives and
> such). There are some examples - but very few - where some other code
> requires us to put code from us in other namespaces, such as some io
> modifiers, or operators for std classes, but this is then clearly visible.
> 
> Nevertheless "using namespace gnc" should rather not be used, as it makes
> the point of namespaces quite moot, as John already said.
> 
Ok, I can live with this as well.

> Also, if there is some sort of "modules" that are used in some places but
> not everywhere, it is also useful to add another level of sub-namespace.
> Such as "gnc::import::", but maybe not quite the "engine", as it is used
> throughout everywhere of our code anyway.
> 
Agreed, adding an "engine" sub-namespace would not add much.

> If there are any nested namespaces, I would strongly recommend to match the
> namespace structure also in the directory names, at least the topmost ones.
> In our case this implies to match this also in the gnc-modules structure.
> 
Good point.

> Apart from this, and for the project of our size, we might very well not
> need more than two levels of namespaces.
> 
Agreed.

> As for the namespace aliases such as "namespace gia =
> gnc::import::aqbanking", those must not appear in header files, but may
> appear in cpp files. However, I didn't like those in general, as it makes
> readability for other people much harder. In terms of mutual readability of
> code, I would rather stick to the plain namespace names and that's it.
> 
Ok. I know we are using them in our new c++ code when referencing certain 
boost namespaces. And the readability aspect works both ways. If namespaces 
get too long, the code becomes hard to read as well. I have found my IDE 
(kdevelop currently) quite helpful in deciphering the aliases. I'm not sure 
which way I like best currently.

Geert