Re: understanding guile-gi

[Chris Vine]

On Sun, 16 Jan 2022 13:37:02 +0000
Zelphir Kaltstahl <zelphirkaltstahl@posteo.de> wrote:
> Hello Guile Users!
> 
> I would like to understand guile-gi better, hopefully at some point I will be
> able to create GTK applications using Guile. But perhaps my understanding is
> wrong, so I want to ask a few things:
> 
> guile-gi – I think this stands for "Guile Gnome(?) Introspection"?

The "gi" stands for gobject-introspection.

> gi – I think this "introspection" part of the name is about inspecting sources
> and deriving code from that, to make use of Gnome libraries. Or is it for GTK?

Instrospection is available for any library with a gobject-introspection
typelib.  That includes glib and GTK and most of the gnome
stack.  /usr/lib[64]/girepository-1.0/ will contain the typelibs
available on your distribution.  There will be many of them.

> Which things are part of GTK and which things are part of Gnome? Currently my
> picture is: GTK contains all the GUI things and Gnome the data things. For
> example: GTK might contain some date picker dialog or popup or whatever, but 
> the
> datatype for date itself would be part of Gnome. "GDate". As such Gnome 
> provides
> a sort of common datatypes basis, which could be used by other frameworks as
> well (and maybe is?).

No.

> So guile-gi makes use of introspection to give access to Gnome datatypes, or
> does it create bindings via FFI for an already existing C code base, which is
> the actual introspection for Gnome stuff?

I am not certain what you mean but gobject-introspection provides
bindings for C libraries written to GObject conventions which make them
available to higher level languages such as python (pygobject),
javascript (gjs) and guile scheme (guile-gi and g-golf).  pygobject is
widely used; gjs is used by gnome-shell amongst others.

> And finally: Is my expectation correct, that I will be able to make GTK
> applications using Guile, if I learn to use guile-gi?

It will mainly work although I believe there are a few missing pieces
which you are unlikely to encounter.  Look at some of the examples in
the guile-gi repository.  Also look at g-golf.