[plt-scheme] make-posn / set-posn-x / graphics.ss

From: Tommy Hallgren (thallgren at yahoo.com)
Date: Tue Dec 17 12:33:06 EST 2002


It seems that make-posn is overloaded by graphics.ss while set-posn-x/y is not.
The simple test program below gives an error if graphics.ss is included but
works just fine if it isn't. And the error message is a bit confusing too:

set-posn-x!: expects args of type <struct:posn>; given instance of a different

I think it's a bad idea to introduce such an inconsistency unless it's because
of a technical problem.


Btw, thanks for an awesome Scheme system!

Regards, Tommy

;(require (lib "graphics.ss" "graphics"))

(define pos (make-posn 0 0))

; set-posn-x & set-posn-y aren't defined in graphics.ss :-(
(set-posn-x! pos 1)
(set-posn-y! pos 2)

(display (posn-x pos)) (newline)
(display (posn-y pos)) (newline)

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