wiki/notebook/literature.courtesCodeStagingGNU2017.org

Code Staging in GNU Guix

• describes the code staging process for package definitions in 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