Re: the benefits of immutability

[Matthias Felleisen <address@hidden>]

On Tuesday, August 19, 2003, at 04:06 PM, Joe Marshall wrote:

> From: "Guy Steele - Sun Microsystems Labs" <Guy.Steele@Sun.COM>
>
>>
>>    From: "Joe Marshall" <jrm@ccs.neu.edu>
>>    To: <vkarvone@mappi.helsinki.fi>
>>    Cc: "Vadim Nasardinov" <el-vadimo@comcast.net>, "Perry E. Metzger"
>> <perry@piermont.com>, <ll1-discuss@ai.mit.edu>
>>    Subject: Re: the benefits of immutability
>>    Date: Tue, 19 Aug 2003 13:19:02 -0400
>>
>>    Hmmm,  a few points off:
>>
>>      1.  When I said `the square root function and the ToString 
>> function'
>>           I intended that those be the `standard' Math.sqrt and
> Object.toString
>>           operators.  Although your `toString' and `sqrt' functions do
> perform
>>           the appropriate operations, they are essentially arbitrary
> objects
>>    with
>>           the appropriate name, not the functions I asked for.
>>
>> What, you don't like (inverse) eta conversion?
>
> C'mon, you know eta conversion is unsound in a typed calculus!
>

Bogus!

    \y:t.M(y) = M for all M : t -> s

Period. Eta conversion is naturally unsound in a call-by-value 
calculus, typed or untyped.

-- Matthias