Convenient OO message sending for Racket

Invoking methods

In Racket, invoking a message foo on an object bar is done with

 #lang racket
 ...
 (send bar foo arg1 arg2 ...)

To make this a little more convenient, prefix your language specification with send-exp, and use curly-braces instead:

 #lang send-exp racket
 ...
 {foo bar arg1 arg2 ...}

Note that the selector comes first, with the receiver argument coming second.

Defining methods

In addition, using #lang send-exp ... adds new syntax for defining methods in a class. In addition to the normal ways of defining a method, you can also use (define {method self arg ...} ...) and (define/override {method self arg ...} ...):

 #lang send-exp racket
 ...
 (class object%
 	...
 	(define {foo self arg1 arg2 ...}
 		...))

The syntax

 (define {selector receiver arg ...) body ...)

is equivalent to

 (define/public (selector arg ...)
 	(let ((receiver this))
 		body ...))

and define/override with curly-braces is analogously equivalent to a use of the underlying define/override syntax.

Abstracting over method calls

In addition to the above, you can use {method} anywhere you would use (lambda (receiver) {method receiver}). This only works for unary methods at present.