lib.mirrorFunctionArgs: init

      importJSON importTOML warn warnIf warnIfNot throwIf throwIfNot checkListOfEnum

      info showWarnings nixpkgsVersion version isInOldestRelease

      mod compare splitByAndCompare

      functionArgs setFunctionArgs isFunction toFunction

      functionArgs setFunctionArgs isFunction toFunction mirrorFunctionArgs

      toHexString toBaseDigits inPureEvalMode;

    inherit (self.fixedPoints) fix fix' converge extends composeExtensions

      composeManyExtensions makeExtensible makeExtensibleWithCustomName;

  isFunction = f: builtins.isFunction f ||

    (f ? __functor && isFunction (f.__functor f));

  /*

    `mirrorFunctionArgs f g` creates a new function `g'` with the same behavior as `g` (`g' x == g x`)

    but its function arguments mirroring `f` (`lib.functionArgs g' == lib.functionArgs f`).

    Type:

      mirrorFunctionArgs :: (a -> b) -> (a -> c) -> (a -> c)

    Example:

      addab = {a, b}: a + b

      addab { a = 2; b = 4; }

      => 6

      lib.functionArgs addab

      => { a = false; b = false; }

      addab1 = attrs: addab attrs + 1

      addab1 { a = 2; b = 4; }

      => 7

      lib.functionArgs addab1

      => { }

      addab1' = lib.mirrorFunctionArgs addab addab1

      addab1' { a = 2; b = 4; }

      => 7

      lib.functionArgs addab1'

      => { a = false; b = false; }

  */

  mirrorFunctionArgs =

    # Function to provide the argument metadata

    f:

    let

      fArgs = functionArgs f;

    in

    # Function to set the argument metadata to

    g:

    setFunctionArgs g fArgs;

  /*

    Turns any non-callable values into constant functions.

    Returns callable values as is.