Returns a function to access a member of an arbitrary object allowing for
null reference, e.g.
(? "to-upper"). This is usually written as
and expanded by the lisp reader to the former expression.
user > (?to-upper "hello") it: "HELLO" user > (?to-upper "hello") it: "HELLO" user > (let obj (new :name "piet")) it: obj user > (?name.to-upper obj) it: "PIET" user > (?city.to-upper obj) it: null user > (.city.to-upper obj) Cannot invoke a method on a null reference:System.Object.ToUpper(null)