[racket] TR Keyword Args (Lil Help)

Bingo.  Thanks.

On Fri, Aug 10, 2012 at 3:43 PM, Sam Tobin-Hochstadt <samth at ccs.neu.edu>wrote:

> On Fri, Aug 10, 2012 at 3:34 PM, Ray Racine <ray.racine at gmail.com> wrote:
> > Sure, I'll probably sketch out a goodly chunk of Plot into TR this
> weekend
> > and will do that modification.
> >
> > My little POC of TRing the Hist* procedures ended translating pretty
> well.
> >
> > https://gist.github.com/3317104
> >
> > The only "bump" I'm still seeing is in attempting to leverage Snip%  out
> of
> > typed/mred/mred.
> >
> > When I try and type
> > (plot (Renderer-Tree ... stuff ... -> (U Snip% Void))
> >
> > running  (test3) fails.
>
> It would be easier for me to tell if you include the error message.
> But probably the issue is that you need (Instanceof Snip%), not just
> Snip%, which is the type of a *class*, not an object.
>
> > What I have now just stubs def-type Image-Snip% with Any, which isn't
> that
> > bad at all.
> >
> > Is it because TR is currently invariant with Classes or did I tickle
> another
> > bug here?  Image-Snip% is a sub-type (class) of Snip%.
> >
> >
> > Say if typed/mred/mred explicitly proved a typed Image-Snip% would
> > everything work?
> >
> > Ray
> >
> >
> > On Fri, Aug 10, 2012 at 3:00 PM, Neil Toronto <neil.toronto at gmail.com>
> > wrote:
> >>
> >> On 08/10/2012 11:54 AM, Sam Tobin-Hochstadt wrote:
> >>>
> >>> On Fri, Aug 10, 2012 at 1:38 PM, Ray Racine <ray.racine at gmail.com>
> wrote:
> >>>>
> >>>> Here https://gist.github.com/3315984
> >>>>
> >>>> The first (test1) works fine.  Note it uses a KW arg.
> >>>>
> >>>> However, (test2) fails.  I thought it was the complexity of the first
> >>>> arg
> >>>> that I was getting wrong.  But when the KW #:label is commented out it
> >>>> works
> >>>> fine.
> >>>
> >>>
> >>> What's happening here is that vectors don't subtype the way lists do,
> >>> so (Vector Symbol Flonum) isn't an appropriate value when you need a
> >>> (Vector Any (U Real False Interval)).  This isn't a problem when you
> >>> don't have the keyword argument, because Typed Racket can figure out
> >>> the needed types from the type of `discrete-histogram`, and so gives
> >>> the vector literals appropriate types.  However, TR doesn't currently
> >>> manage to propagate this information when looking at keyworded
> >>> applications, which are much more complex when expanded.  Thus the
> >>> behavior you're seeing.
> >>>
> >>> If we give TR a little help here, then this works:
> >>>
> >>> (define: lst : (Listof (Vector Any (U Real False Interval)))
> >>>    (list #(A 1.0) #(B 2.0) #(B 3.0) (vector 'C (ivl 0.5 1.5))))
> >>>
> >>> (define (test2)
> >>>    (plot (discrete-histogram lst #:label "Hello")))
> >>>
> >>> One way that `plot` could make this easier would be to support lists
> >>> in addition to vectors for histogram data.
> >>
> >>
> >> That wouldn't be hard to change. The contract and function are both
> >> defined in the file "plot/plot2d/rectangle.rkt". You want to take a
> crack at
> >> it, Ray? :)
> >>
> >> You should only have to change the contract of `cat-vals' in
> >> `discrete-histogram' (to se `or/c'), and change the match pattern that
> >> destructures it to (list (or (vector cats ys) (list cats ys)) ...).
> >>
> >> Neil ⊥
> >>
> >>
> >> ____________________
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> >
> >
> >
> > ____________________
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> >
>
>
>
> --
> sam th
> samth at ccs.neu.edu
>
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