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 1 > (?to-upper "hello")
it: "HELLO"
user 2 > (?to-upper "hello")
it: "HELLO"
user 3 > (let obj (new :name "piet"))
it: #s( :name "piet" )
user 4 > (?name.to-upper obj)
it: "PIET"
user 5 > (?city.to-upper obj)
it: null
user 6 > (.city.to-upper obj)
Cannot invoke a method on a null reference:System.Object.ToUpper(null)