Editing Mutator method (section)

===Racket===
In [[Racket (programming language)|Racket]], the object system is a way to organize code that comes in addition to modules and units.  As in the rest of the language, the object system has first-class values and lexical scope is used to control access to objects and methods.

<syntaxhighlight lang="racket">
#lang racket
(define student%
  (class object%
    (init-field name)
    (define/public (get-name) name)
    (define/public (set-name! new-name) (set! name new-name))
    (super-new)))

(define s (new student% [name "Alice"]))
(send s get-name)                       ; => "Alice"
(send s set-name! "Bob")
(send s get-name)                       ; => "Bob"
</syntaxhighlight>

Struct definitions are an alternative way to define new types of values, with mutators being present when explicitly required:
<syntaxhighlight lang="racket">
#lang racket
(struct student (name) #:mutable)
(define s (student "Alice"))
(set-student-name! s "Bob")
(student-name s)                        ; => "Bob"
</syntaxhighlight>