nixpkgs/lib/systems/default.nix
John Ericson bc9f471997 Merge pull request #27797 from grahamc/fixed-lib
Convert libs to a fixed-point
2017-09-19 10:52:15 -04:00

45 lines
1.7 KiB
Nix

{ lib }:
let inherit (lib.attrsets) mapAttrs; in
rec {
doubles = import ./doubles.nix { inherit lib; };
parse = import ./parse.nix { inherit lib; };
inspect = import ./inspect.nix { inherit lib; };
platforms = import ./platforms.nix { inherit lib; };
examples = import ./examples.nix { inherit lib; };
# 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";
extensions = {
sharedLibrary =
/**/ if final.isDarwin then ".dylib"
else if final.isWindows then ".dll"
else ".so";
executable =
/**/ if final.isWindows then ".exe"
else "";
};
} // mapAttrs (n: v: v final.parsed) inspect.predicates
// args;
in final;
}