brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.
Vala is a new programming language that aims to bring modern programming
language features to GNOME developers without imposing any additional runtime
requirements and without using a different ABI compared to applications and
libraries written in C.
David Höppner
Max Howell