For instance, the Mesa Nix expression says:

target =
if stdenv.system == “i686-linux” then “linux-dri-x86” else
if stdenv.system == “x86_64-linux” then “linux-dri-x86-64” else
abort “unsupported platform for Mesa”;

However, this causes evaluation to fail entirely on other platforms. So its better to use throw, which is caught automatically by “nix-env -qa” at top-level. This allows us to get rid of some assertions in all-packages.nix (for instance, the mesaSupported tests).

Submitted on 16 May 2007 at 16:48