Lose Enden - What it is all about.

The release of GNOME 3 included more than a visual overhaul. The underlying libraries were partly cleaned up and gained new features.

One of these features that gained more ground was gobject introspection (gi). Libraries using GObject can then easily be called from languages like python or Javascript if the support introspection.

This is where vala jumps in. Vala is language which tries to support the C# syntax but uses GObject and compiles to C, which then is compiled into binaries using common C compilers.

So what is the benefit? As all executables and libraries created by vala or based on GObject, their functions and classes etc. can be called natively from gjs (a JavaScript interpreter) and python (using pygi)
Also most GNOME related libraries are build using GObject.

This leads us to the situation where you can use a scripting language and have access to a comprehensive stack of libraries regarding the GNOME desktop environment.

• Rapid development? JavaScript.
• Layout? Glade.
• Style? CSS.
• Library? Vala.

It's not just theory. Look at gnome-shell or gnome-documents.