Cabal flags can be interpreted by cabal2nix

[CMCDragonkai]

If you see something like:

executable Generate
  if flag(Generators)
    Buildable: True
  else
    Buildable: False
  hs-source-dirs: Scripts
  main-is: Generate.hs
  other-modules: Helpers
  default-language: Haskell2010
  ghc-options: -Wall

  if flag(Generators)
    build-depends: base >=4.6 && <5,
                   language-c <0.7,
                   containers,
                   process,
                   regex-pcreexecutable Generate
  if flag(Generators)
    Buildable: True
  else
    Buildable: False
  hs-source-dirs: Scripts
  main-is: Generate.hs
  other-modules: Helpers
  default-language: Haskell2010
  ghc-options: -Wall

  if flag(Generators)
    build-depends: base >=4.6 && <5,
                   language-c <0.7,
                   containers,
                   process,
                   regex-pcre

In the cabal file:

You basically have to do:

cabal2nix --flag Generators . >./cabal.nix

Render this into the README.md.

[CMCDragonkai]

But if this is done, the shell.nix needs to be changed so when it runs cabal configure, it also runs with the flag, and also when cabal2nix is used. So something like cabal configure -f Generators. Also note that there's a minus version which means the flag is set to false. Not sure about that maybe some flags can be by default true.

[CMCDragonkai]

@ksenia-portu This is relevant to you.