Are you referring to the special case on line 2730 of teach.rkt when you say posns?
I think that means that I'd have to make the teaching language depend on 2htdp/image, which doesn't seem right. I would have thought that the right thing would be to extend the define-primitive protocol so that I can declare that 'color' is both a function and a struct constructor and then match would not have to special case 'color'. No? Robby On Mon, Oct 31, 2011 at 9:48 PM, Jay McCarthy <jay.mccar...@gmail.com> wrote: > The HtDP match implementation has a list of such things and goes and > finds them to turn them back into the non-primitive bound things. > That's why it works with posns. > > Something better could be done, but for now you could add it to the white > list. > > Jay > > On Mon, Oct 31, 2011 at 8:45 PM, Robby Findler > <ro...@eecs.northwestern.edu> wrote: >> Oh, I see why. 'color' is bound using define-primitive in order to >> cooperate with the beginner language (and so that 'color' can be a >> constructor). But doing that interferes with the usual information >> bound by a struct that match picks up. >> >> I'm not sure what the right way to resolve this is. >> >> Robby >> >> On Mon, Oct 31, 2011 at 9:39 PM, Robby Findler >> <ro...@eecs.northwestern.edu> wrote: >>> Is make-color coming from 2htdp/image? I see that's not working (not >>> sure why yet). >>> >>> Robby >>> >>> On Mon, Oct 31, 2011 at 9:34 PM, Adam Shaw <adams...@cs.uchicago.edu> wrote: >>>> Thanks! That still doesn't work for color: >>>> match: color does not refer to a structure definition >>>> although it does work with my own custom color struct: >>>> (define-struct clr (r g b)) >>>> (match (make-clr 1 2 3) >>>> [(struct clr (r g b)) (* r g b)]) >>>> - Adam >>>> On Oct 31, 2011, at 9:26 PM, Jay McCarthy wrote: >>>> >>>> One of the branches of the pattern language is >>>> >>>> | (struct id (pattern ...)) >>>> >>>> Your pattern should be >>>> >>>> (struct color (r g b)) >>>> >>>> >>>> _________________________________________________ >>>> For list-related administrative tasks: >>>> http://lists.racket-lang.org/listinfo/users >>>> >>> >> > > > > -- > Jay McCarthy <j...@cs.byu.edu> > Assistant Professor / Brigham Young University > http://faculty.cs.byu.edu/~jay > > "The glory of God is Intelligence" - D&C 93 > _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
