1 Classes and Objects

(require (planet cce/scheme:3:0/class))

This module provides tools for classes, objects, and mixins.

1.1 Predicates and Contracts

class-or-interface/c : flat-contract?

Recognizes classes and interfaces.

(object/c spec ...) → flat-contract?

spec : class-or-interface/c

Recognizes objects which are instances of all the given classes and interfaces.

(class/c spec ...) → flat-contract?

spec : class-or-interface/c

Recognizes classes which are subclasses (not strictly) and implementations, respectively, of all the given classes and interfaces.

(mixin/c [super-expr ...] [arg-expr ...] [sub-expr ...])

Function contract for a mixin whose first argument is the parent class c% matching (class/c super-expr ...), whose remaining arguments match arg-expr ..., and whose result matches (class/c c% sub-expr ...).

1.2 Mixins

(ensure-interface i<%> mx c%) → (class/c c% i<%>)

i<%> : interface?

mx : (mixin/c [] [] [i<%>])

c% : class?

Returns c% if it implements i<%>; otherwise, returns (mx c%).

1.3 Methods

(send+ obj [message arg ...] ...)

Sends each message (with arguments) to obj, then returns obj.

Examples:

(define c%     (class object%       (super-new)       (define/public (say msg) (printf "~a!\n" msg))))

> (send+ (new c%) [say 'Hello] [say 'Good-bye])

Hello!   Good-bye!

#(struct:object:c% ...)

(send-each objs message arg ...)

Sends the message to each object in the list objs, returning (void).

Examples:

(define c%     (class object%       (super-new)       (init-field msg)       (define/public (say to) (printf "~a, ~a!\n" msg to))))

> (send-each      (list (new c% [msg 'Hello])            (new c% [msg 'Good-bye]))      say 'World)

Hello, World!   Good-bye, World!