nix-GINsim/shell.nix

# shell.nix
#
# Prepare a Nix shell with GINsim available.
#
# Use nix-shell or nix-shell shell.nix to start.

# The with statement imports the nixpkgs namespace, so the tools like
# stdenv and callPackage become available.
with import <nixpkgs> {};
stdenv.mkDerivation {
  name = "GINsim-shell";

  # Bring the package defined in ginsim.nix in scope.  buildInputs is
  # therefore a one-element list.  Its only element is the call of the
  # anonymous function defined in ginsim.nix.  I could have used let
  # to define a local binding ginsim = callPackage ./ginsim.nix {}; to
  # explicitly bind a name to this function call.
  #
  # callPackage can also be replaced by import.  In this case, the
  # arguments of the anonymous function defined in ginsim.nix get
  # their respective default values.
  buildInputs = [ (callPackage ./ginsim.nix {}) ];
}