:PROPERTIES:
:ID:       11ad06b1-c3ad-4675-9fc0-f651bd62a6d7
:ROAM_REFS: [cite:@courtesCodeStagingGNU2017]
:END:
#+title: Code Staging in GNU Guix
#+date: 2022-06-11 17:36:08 +08:00
#+date_modified: 2022-06-11 18:10:24 +08:00>
#+published: 2017-10-23
#+author: Courtès, L.
#+source: https://hal.inria.fr/hal-01580582
#+language: en


- describes the code staging process for package definitions in [[id:be917383-84c4-4bf5-9ca0-b04bfb778f4f][Guix package manager]];
  mainly describing [[roam:Guix G-expressions]]
- creating package definitions often certain parts of the definitions to carry through the build stage;
  oftentimes, these parts of code include additional build instructions for non-trivial packages and additional inputs for that package
- while S-expressions (sexp) are nice, they can be verbose at times;
  this is where G-expressions (gexp) comes in handy
  - gexp are hygenic — they preserve lexical scope across different stages
  - they can easily refer to the high-level objects (e.g., packages, local file) in the store (i.e., ~/gnu/store~)
  - first-class Scheme values
  - binds deployment to staging — when brought into staging, all inputs are also deployed as well
- use cases for gexps
  - code sharing between multiple stages;
    this is mostly present such as defining packages and building them
  - cross-compilation — there are additional operators to denote "nativeness" where it will refer to the "native" version rather than the target version
  - package definitions — less verbose definitions which is always nice especially with the use of referring to the absolute file names from the store
  - system services — the process and lifecycle of system services is similar to defining packages being composed of multiple stages: one in definition and one in building the services in the init system
  - system tests — they can be defined through the =operating-system= interface which are derivations describing entire operating systems;
    in Guix, this is implemented through a tool called =marionette= which introduces another stage in the pipeline