[racket-dev] Machinery for eliding contracts

Yes, I think this would allow all the optimizations that Eric talked about.

Sam
On Jun 13, 2014 4:26 AM, "Robby Findler" <robby at eecs.northwestern.edu>
wrote:

> Would it be useful to get blame information back from a value, just
> like you can currently get the contract back?
>
> Robby
>
> On Tue, Jun 10, 2014 at 11:53 AM, Matthias Felleisen
> <matthias at ccs.neu.edu> wrote:
> >
> > I was thinking of associating the contract with the type from which it
> comes and no that's not hash-consing. And if it's slower, too bad. --
> Matthias
> >
> >
> >
> >
> >
> > On Jun 10, 2014, at 12:47 PM, Eric Dobson <eric.n.dobson at gmail.com>
> wrote:
> >
> >> On Tue, Jun 10, 2014 at 6:15 AM, Matthias Felleisen
> >> <matthias at ccs.neu.edu> wrote:
> >>>
> >>> On Jun 9, 2014, at 6:02 PM, Eric Dobson <eric.n.dobson at gmail.com>
> wrote:
> >>>
> >>>>>
> >>>>> Eric, are you talking about changing the proxy values that wrap
> HO/mutable
> >>>>> contracted values?
> >>>> Yes. I want the proxy values to include information about who agreed
> >>>> to the contract in addition to the contract agreed to.
> >>>>
> >>>> I actually realize that I might need more than just the contract
> >>>> agreed to because of how TR changes the generated contract to remove
> >>>> checks for what it guarantees, so that info is not in the contract.
> >>>> But I believe that can be added back as a structure property on the
> >>>> contract.
> >>>
> >>>
> >>> Would some form of hash-consing contracts work here? -- Matthias
> >>>
> >>
> >> I don't think so. But not sure exactly what you are proposing.
> >>
> >> The issue is that there are 4 contracts here and 2 of them currently
> >> do not exist at runtime. The 4 are TRs checks/promises on an
> >> export/import. (Using import for a value flowing into an exported
> >> function). The promise contracts do not currently exist as removing
> >> them was my previous optimization (They never fail). What I want to do
> >> is change the check on import from (array/c symbol?) to (if/c
> >> (protected>? (array/c symbol?)) any/c (array/c symbol?)). Where
> >> (protected>? x/c) checks if TR already promised something stronger
> >> than x/c.
> >>
> >> I believe that you are proposing that we can use the identity of the
> >> contract returned by value-contract to determine what the promised
> >> contract would have been. This does not work as (Array Symbol) and
> >> (Array Float) both get translated to (array/c any/c) for export, and
> >> we would want to lookup different promised contracts for them. We
> >> could use weak hash map as an extra field but that seems like it would
> >> be slow.
> >
> >
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