[racket-dev] Machinery for eliding contracts

I believe thats what I need for the optimization-half, but I don't
think it allows for soundly implementing the optimizations.

I still don't see how to test if a value came from TR instead of
someone trying to fake that, especially if they can get the blame
object from one export and reuse it on a different value.

On Fri, Jun 13, 2014 at 6:29 AM, Robby Findler
<robby at eecs.northwestern.edu> wrote:
> Okay, I'll push has-blame? and value-blame. Let me know if there are
> any problems.
>
> Robby
>
> On Fri, Jun 13, 2014 at 5:59 AM, Sam Tobin-Hochstadt
> <samth at cs.indiana.edu> wrote:
>> 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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