Preamble - What is hackage

[JonathanLorimer]

file to edit: https://github.com/haskell/cabal-userguide/blob/main/src/preamble/03_what_is_hackage.md

Brief Summary

Hackage is a key piece of haskell infrastructure. It is also critical to cabal, and (in my opinion) receives very little treatment in documentation in comparison to how critical it is. This chapter should go over key hackage features and why they are important for someone who wants to use Cabal.

Resources

Hackage Website
How Cabal uses hackage

[Mikolaj]

My 0.5c jumping ahead (probably not or not all in Preamble): perhaps worth mentioning the revisions of packages on Hackage (so Hackage can have a version of package that compiles with GHC X while github repo does not), Stackage/LTS that takes packages from Hackage (not sure if only from there?) and that takes the revisions as well, so revisions are not just some frivolous local Hackage hacks. Also, anybody can ask Hackage Trustees (via a ticket) to make a revision if a maintainer is too busy to accept a PR.