[bug#40629] Build and install packages from JSON definitions

[Ricardo Wurmus <rekado@elephly.net>]

Hi Guix,

did you know that we have JSON importer?  Admittedly, it’s not very
useful because people don’t generally use JSON syntax to define Guix
packages.  Not even Guix lets you build and install packages from JSON
definitions, so what’s the point really?

Well, fret not!  This patch set adds support for JSON package
definitions to “guix package -f” and “guix build -f”.  You can now dump
this into a file “hello.json”:

--8<---------------cut here---------------start------------->8---
{
  "name": "hello",
  "version": "2.10",
  "source": "mirror://gnu/hello/hello-2.10.tar.gz",
  "build-system": "gnu",
  "home-page": "https://www.gnu.org/software/hello/",
  "synopsis": "Hello, GNU world: An example GNU package",
  "description": "GNU Hello prints a greeting.",
  "license": "GPL-3.0+",
  "native-inputs": ["gettext"]
}
--8<---------------cut here---------------end--------------->8---

and then install the hello package with “guix package -f hello.json”
without having to first run the JSON importer.

Since the JSON importer doesn’t know how to work with more than one
definition you can’t have more than one custom definition in your JSON
file, but if there’s interest we can easily add support for this.

(My patch set does not come with documentation changes for “guix
package” or “guix build”.)

What do you think?

--
Ricardo