[e-lang] [Caja] Functional auditor for Cajita

[Mark S. Miller]

On Tue, Dec 8, 2009 at 2:06 PM, Mike Samuel <mikesamuel at gmail.com> wrote:
> Is the following copacetic by that definition?
>
>  (function (eval, s) {
>    eval(s);
>  })
>
> If passed the arguments (freeze(eval), 'a = 0') it will modify the
> lexical environment, and I think both arguments are copacetic
> according to the frozen functions definition,

Aren't we presuming Cajita, in which case this is illegal? If instead
full ES5-strict, then the above "eval(s)" code should be considered a
special form causing all variables in its lexical scope to be
considered accessible and (if assignable) potentially assigned.


>
>
> 2009/12/8  <ihab.awad at gmail.com>:
>> On Tue, Dec 8, 2009 at 12:05 PM, David-Sarah Hopwood
>> <david-sarah at jacaranda.org> wrote:
>>> Note that this implies that the lexical environment of each successfully
>>> created instance is observationally immutable, not just that it can't
>>> be directly changed by that instance. I.e. it also can't be changed
>>> indirectly via an operation on an argument ...
>>
>> D'oww, I missed that one! Yes, thank you.
>>
>>> The implementation sketch I gave would preclude that use case because
>>> if the supplied argument values are not copacetic, the object's read()
>>> method would throw. This might have been too conservative -- if those
>>> argument checks were omitted then the property above (that the function
>>> instance can't change its lexical environment) would still hold.
>>
>> Yes.
>>
>>> It would be possible to make the argument and result checks optional
>>> depending on the function annotation: say, /*@pure*/ includes them but
>>> /*@functional*/ doesn't. (The environment checks would be the same,
>>> and both /*@pure*/ and /*@functional*/ would mark instances as
>>> copacetic.)
>>
>> Yeah I think we're talking about two, possibly both useful classes of
>> behavior here.
>>
>>> What a fun discussion! Thanks for starting it.
>>
>> Glad to oblige. :)
>>
>> Ihab
>>
>> --
>> Ihab A.B. Awad, Palo Alto, CA
>>
>



-- 
    Cheers,
    --MarkM