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typesetting/pitfall/sugar/class.rkt

71 lines
2.2 KiB
Racket

#lang racket/base
(require (for-syntax racket/base racket/syntax br/syntax) br/define racket/class)
(provide (all-defined-out))
(define string%
(class* object% (writable<%>)
(super-new)
(init-field [data #f])
(define (get-string)
(with-handlers ([exn:fail:object? (λ (exn) data)])
(send this toString)))
(define/public (custom-write port) (write (get-string) port))
(define/public (custom-display port) (display (get-string) port))))
(define mixin-tester%
(class object%
(super-new)
(define/public (addContent val) (make-object string% val))))
(define-macro (as-method ID)
(with-pattern ([PRIVATE-ID (generate-temporary #'ID)])
#'(begin
(public [PRIVATE-ID ID])
(define (PRIVATE-ID . args) (apply ID this args)))))
(define-macro (as-methods ID ...)
#'(begin (as-method ID) ...))
(define-macro (define-subclass SUPERCLASS (ID . INIT-ARGS) . BODY)
#'(define-subclass* SUPERCLASS (ID . INIT-ARGS) (super-new) . BODY))
(define-macro (define-subclass* SUPERCLASS (ID . INIT-ARGS) . BODY)
(with-pattern ([+ID (prefix-id "+" #'ID)]
[ID? (suffix-id #'ID "?")])
#'(begin
(define ID (class SUPERCLASS (init-field . INIT-ARGS) . BODY))
(define (ID? x) (is-a? x ID))
(define (+ID . args) (apply make-object ID args)))))
(define-macro (push-field! FIELD O EXPR)
#'(set-field! FIELD O (cons EXPR (get-field FIELD O))))
(define-macro (push-end-field! FIELD O EXPR)
#'(set-field! FIELD O (append (get-field FIELD O) (list EXPR))))
(define-macro (pop-field! FIELD O)
#'(let ([xs (get-field FIELD O)])
(set-field! FIELD O (cdr xs))
(car xs)))
(define-macro-cases increment-field!
[(_ FIELD O) #'(increment-field! FIELD O 1)]
[(_ FIELD O EXPR)
#'(begin (set-field! FIELD O (+ (get-field FIELD O) EXPR)) (get-field FIELD O))])
(define-macro (getter-field/override [ID . EXPRS])
(syntax-property #'(getter-field [ID . EXPRS]) 'override #t))
(define-macro (getter-field [ID . EXPRS])
(with-pattern ([_ID (prefix-id "_" #'ID)])
#`(begin
(field [(ID _ID) . EXPRS])
(public (_ID ID))
(#,(if (syntax-property caller-stx 'override) #'define/override #'define) (_ID) ID))))