@function __result($map, $key, $default-value: null) {
    $value: if($map == null, $__undefined__, __get($map, $key));
    $result: null;

    @if __is-undefined($value) or __is-null($value) {
        $value: $default-value;
    }

    @if __function-exists($value) {
        $_: __scope($map);
        $scoped-function: __bind($value);
        $result: __call($scoped-function, $__current-scope__);
        $_: __scope(false);
    } @else {
        $result: $value;
    }

    @return $result;
}


/// Resolves the value of property `$key` on `$map`. If the value of `key` is
/// a function it is invoked with the `_this` binding of `$map` and its result
/// is returned, else the property value is returned. If the property value is
/// `undefined` or `null` the `$default-value` is used in its place.
///
///
/// @access public
/// @group Map
/// @param {Map} $map The $map to query.
/// @param {string} $key The key of the property to resolve.
/// @param {*} $default-value The value returned if the property value
///  resolves to `undefined` or `null`.
/// @returns {*} Returns the resolved value.
/// @example scss
/// $map: ( 'user': 'fred', 'age': _constant(40) );
/// $foo: _result($map, 'user');
/// // => 'fred'
/// $foo: _result($map, 'age');
/// // => 40
/// $foo: _result($map, 'status', 'busy');
/// // => 'busy'
/// $foo: _result($map, 'status', _constant('busy'));
/// // => 'busy'

@function _result($args...) {
    @return call(get-function('__result'), $args...);
}