[racket-dev] Machinery for eliding contracts

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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