129 lines
3.9 KiB
Racket
129 lines
3.9 KiB
Racket
#lang scribble/manual
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@(require scribble/eval
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"utils.rkt"
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(for-label unstable/class-iop
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racket/class
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racket/contract
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racket/base))
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@title[#:tag "class-iop"]{Interface-Oriented Programming for Classes}
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@(define the-eval (make-base-eval))
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@(the-eval '(require racket/class unstable/class-iop))
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@defmodule[unstable/class-iop]
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@unstable[@author+email["Ryan Culpepper" "ryanc@racket-lang.org"]]
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@defform[(define-interface name-id (super-ifc-id ...) (method-id ...))]{
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Defines @racket[name-id] as a static interface extending the
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interfaces named by the @racket[super-ifc-id]s and containing the
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methods specified by the @racket[method-id]s.
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A static interface name is used by the checked method call variants
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(@racket[send/i], @racket[send*/i], and @racket[send/apply/i]). When
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used as an expression, a static interface name evaluates to an
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interface value.
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@examples[#:eval the-eval
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(define-interface stack<%> () (empty? push pop))
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stack<%>
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(define stack%
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(class* object% (stack<%>)
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(define items null)
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(define/public (empty?) (null? items))
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(define/public (push x) (set! items (cons x items)))
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(define/public (pop) (begin (car items) (set! items (cdr items))))
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(super-new)))
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]
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}
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@defform[(define-interface/dynamic name-id ifc-expr (method-id ...))]{
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Defines @racket[name-id] as a static interface with dynamic
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counterpart @racket[ifc-expr], which must evaluate to an interface
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value. The static interface contains the methods named by the
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@racket[method-id]s. A run-time error is raised if any
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@racket[method-id] is not a member of the dynamic interface
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@racket[ifc-expr].
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Use @racket[define-interface/dynamic] to wrap interfaces from other
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sources.
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@examples[#:eval the-eval
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(define-interface/dynamic object<%> (class->interface object%) ())
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object<%>
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]
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}
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@defform[(send/i obj-exp static-ifc-id method-id arg-expr ...)]{
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Checked variant of @racket[send].
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The argument @racket[static-ifc-id] must be defined as a static
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interface. The method @racket[method-id] must be a member of the
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static interface @racket[static-ifc-id]; otherwise a compile-time
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error is raised.
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The value of @racket[obj-expr] must be an instance of the interface
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@racket[static-ifc-id]; otherwise, a run-time error is raised.
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@examples[#:eval the-eval
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(define s (new stack%))
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(send/i s stack<%> push 1)
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(send/i s stack<%> popp)
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(send/i (new object%) stack<%> push 2)
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]
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}
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@defform[(send*/i obj-expr static-ifc-id (method-id arg-expr ...) ...)]{
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Checked variant of @racket[send*].
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@examples[#:eval the-eval
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(send*/i s stack<%>
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(push 2)
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(pop))
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]
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}
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@defform[(send/apply/i obj-expr static-ifc-id method-id arg-expr ... list-arg-expr)]{
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Checked variant of @racket[send/apply].
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@examples[#:eval the-eval
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(send/apply/i s stack<%> push (list 5))
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]
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}
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@defform[(define/i id static-ifc-id expr)]{
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Checks that @racket[expr] evaluates to an instance of
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@racket[static-ifc-id] before binding it to @racket[id]. If
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@racket[id] is subsequently changed (with @racket[set!]), the check is
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performed again.
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No dynamic object check is performed when calling a method (using
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@racket[send/i], etc) on a name defined via @racket[define/i].
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}
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@deftogether[[
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@defform[(init/i (id static-ifc-id maybe-default-expr) ...)]
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@defform[(init-field/i (id static-ifc-id maybe-default-expr) ...)]
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@defform/subs[(init-private/i (id static-ifc-id maybe-default-expr) ...)
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([maybe-default-expr (code:blank)
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default-expr])]]]{
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Checked versions of @racket[init] and @racket[init-field]. The value
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attached to each @racket[id] is checked against the given interface.
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No dynamic object check is performed when calling a method (using
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@racket[send/i], etc) on a name bound via one of these forms. Note
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that in the case of @racket[init-field/i] this check omission is
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unsound in the presence of mutation from outside the class. This
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should be fixed.
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}
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