nixpkgs.lib.setFunctionArgs

(a -> b) -> AttrSets -> { __functor = any -> a -> b; __functionArg = AttrSets }

第1引数の関数に渡す予定の引数を第2引数で受け取りそれを保持しておくオブジェクトを返す関数。nixpkgs.lib.functionArgsで引数を取り出すことができる。

code: trivial.nix

/* Add metadata about expected function arguments to a function.

The metadata should match the format given by

builtins.functionArgs, i.e. a set from expected argument to a bool

representing whether that argument has a default or not.

setFunctionArgs : (a → b) → Map String Bool → (a → b)

This function is necessary because you can't dynamically create a

function of the { a, b ? foo, ... }: format, but some facilities

like callPackage expect to be able to query expected arguments.

setFunctionArgs = f: args:

{ # TODO: Should we add call-time "type" checking like built in?

__functor = self: f;

__functionArgs = args;

};