Name

?

Usage

builtin-function

Syntax

(? members)

Description

Returns a function to access a member of an arbitrary object allowing for null reference, e.g. (? "to-upper"). This is usually written as ?to-upper 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)