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(define-module (starlet colours)
#:use-module (oop goops)
#:export (<colour>
make-colour-cmy
make-colour-rgb
colour-as-cmy
white))
(define-class <colour> (<object>)
(type
#:init-form (error "Colour type must be specified")
#:init-keyword #:type
#:getter colour-type)
(value
#:init-form (error "Colour value must be specified")
#:init-keyword #:value
#:getter colour-value))
(define cyan car)
(define magenta cadr)
(define yellow caddr)
(define-method (display (col <colour>) port)
(format port "#<<colour> ~a ~a>"
(colour-type col)
(colour-value col)))
(define-method (write (col <colour>) port)
(let ((cmy (colour-as-cmy col)))
(format port "(make-colour-cmy ~a ~a ~a)"
(cyan cmy)
(magenta cmy)
(yellow cmy))))
(define (make-colour-cmy c m y)
(make <colour>
#:type 'cmy
#:value (list c m y)))
(define (make-colour-rgb r g b)
(make <colour>
#:type 'rgb
#:value (list r g b)))
(define white
(make-colour-cmy 0 0 0))
(define (colour-as-cmy col)
(colour-value col))
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