[plt-scheme] Questions about contracts

From: Chongkai Zhu (czhu at cs.utah.edu)
Date: Tue Apr 17 21:23:16 EDT 2007

Thank you very much. The new combinator seems to cover all cases I know that doesn't work with yesterday's contract system, although I need to read the doc to make sure.


----- Original Message ----- 
From: "Robby Findler" <robby at cs.uchicago.edu>
To: "Chongkai Zhu" <czhu at cs.utah.edu>
Cc: "pltscheme" <plt-scheme at list.cs.brown.edu>
Sent: Tuesday, April 17, 2007 1:04 PM
Subject: Re: [plt-scheme] Questions about contracts

> On 4/16/07, Chongkai Zhu <czhu at cs.utah.edu> wrote:
>> Than my question is: how to write a correct contract
>> for cases like this?
> I think that it wasn't possible to express that contract in
> yesterday's contract system. So, I've added a new contract combinator.
> It accepts functions and puts no constraints on their arities, but
> does but a constraint on their ranges. You can combine this with other
> contracts to get the effect you (seem to) want.
> Below is an example use (the docs should be out tomorrow when the
> nightly build completes). In general, unconstrained-domain-> accepts
> one argument for each (multiple value) result the function produces
> and it puts no constraint on the arity of the function.
> I hope that helps.
> Robby

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