nixpkgs/lib/systems/default.nix
John Ericson c5c6606048 lib: Infer libc field of platform if not specified
This is especially useful when not cross compiling. It means we can
remove the `stdenv.isGlibc` predicate too.

Additionally, use this to simplify the logic to choose the
appropriate libiconv derivation.
2017-05-22 00:25:02 -04:00

34 lines
1.3 KiB
Nix

let inherit (import ../attrsets.nix) mapAttrs; in
rec {
doubles = import ./doubles.nix;
parse = import ./parse.nix;
inspect = import ./inspect.nix;
platforms = import ./platforms.nix;
# Elaborate a `localSystem` or `crossSystem` so that it contains everything
# necessary.
#
# `parsed` is inferred from args, both because there are two options with one
# clearly prefered, and to prevent cycles. A simpler fixed point where the RHS
# always just used `final.*` would fail on both counts.
elaborate = args: let
final = {
# Prefer to parse `config` as it is strictly more informative.
parsed = parse.mkSystemFromString (if args ? config then args.config else args.system);
# Either of these can be losslessly-extracted from `parsed` iff parsing succeeds.
system = parse.doubleFromSystem final.parsed;
config = parse.tripleFromSystem final.parsed;
# Just a guess, based on `system`
platform = platforms.selectBySystem final.system;
libc =
/**/ if final.isDarwin then "libSystem"
else if final.isMinGW then "msvcrt"
else if final.isLinux then "glibc"
# TODO(@Ericson2314) think more about other operating systems
else "native/impure";
} // mapAttrs (n: v: v final.parsed) inspect.predicates
// args;
in final;
}