@function __base-property-function($map: null, $args...) {
    $key: __this('key');

    @if __is-falsey($map) {
        @return null;
    }

    $map: __to-map($map);

    @return if($map == null, null, __get($map, $key));
}


@function __base-property($key) {
    $_: __scope((
        'key': $key
    ));
    $base-property-function: __bind('__base-property-function');
    $_: __scope(false);

    @return $base-property-function;
}


@function __property($key, $args...) {
    @return __base-property($key);
}


@function __property-of-function($key, $args...) {
    $map: __this('map');

    @return if($map == null, null, __get($map, $key));
}


@function __property-of($map, $args...) {
    $_: __scope((
        'map': $map
    ));
    $property-of-function: __bind('__property-of-function');
    $_: __scope(false);

    @return $property-of-function;
}


/// Creates a function which returns the property value of `$key` on a given map.
///
///
/// @access public
/// @group Utility
/// @param {string} $key The key of the property to get.
/// @returns {Function} Returns the new function.
/// @example scss
/// $users: (
///   ( 'user': 'fred' ),
///   ( 'user': 'barney' )
/// );
/// 
/// $get-name: _property('user');
///
/// $foo: _map($users, $get-name);
/// // => ('fred', barney')
///
/// $foo: _pluck(_sort-by($users, $get-name), 'user');
/// // => ('barney', 'fred')

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


/// The inverse of `_property`; this method creates a function which returns
/// the property value of a given key on `$map`.
///
///
/// @access public
/// @group Utility
/// @param {Map} $map The map to inspect.
/// @returns {Function} Returns the new function.
/// @example scss
/// $map: ( 'a': 3, 'b': 1, 'c': 2 );
/// $foo: _map(('a', 'c'), _property-of($map));
/// // => (3, 2)
/// $foo: _sort-by(('a', 'b', 'c'), _property-of($map));
/// // => ('b', 'c', 'a')

@function _property-of($args...) {
    @return call(get-function('__property-of'), $args...);
}