nixrc/lib/list-to-bash-array.nix

# Source: http://chriswarbo.net/projects/nixos/useful_hacks.html

{ args, name }:
  let
    nixpkgs = import <nixpkgs> {};
    lib = nixpkgs.lib;
  in
    rec {
      # Store each arg in a separate variable, named numerically
      env = with lib.foldl' (result: arg: {
                          # Increment the count, for the next arg (if any)
                          count = result.count + 1;

                          # Append a variable to the environment for this arg
                          vars  = result.vars // {
                            "${name}${toString result.count}" = arg;
                          };
                        })
                        # Start with variable 1 in an empty environment
                        { count = 1; vars = {}; }
                        args;
            vars;

      code = ''
        ### Auto-generated by nixListToBashArray
        ${name}=()

        for N in $(seq 1 "${toString (lib.length args)}")
        do
          # Use a "variable variable" to look up "$name$N" as a variable name
          NIXLISTTOBASHARRAYTEMP="${name}$N"
          ${name}=("''${${name}[@]}" "''${!NIXLISTTOBASHARRAYTEMP}")
          unset NIXLISTTOBASHARRAYTEMP
        done
        ### End of auto-generated code
      '';
    }