Re: [stack] function/object ambiguity + quotation alternative

----- Original Message ----- 
From: "John Nowak" <[email protected]>
To: <[email protected]>
Sent: Friday, February 27, 2009 7:03 PM
Subject: Re: [stack] function/object ambiguity + quotation alternative


> 
> On Feb 27, 2009, at 6:00 PM, Stevan Apter wrote:
> 
>> everything on the stack is a noun, everything on the queue is a verb.
>> so we can rewrite your reduction, without ambiguity, as stack | queue:
>>
>>          | 2 [dup] first
>>  2       | [dup] first
>>  2 [dup] | first
>>  2 dup   |
> 
> Indeed you can. Or you can rewrite it without ambiguity using an  
> explicit stack.
> 
> The trouble is that both approaches make it impossible to reduce in an  
> arbitrary order and at arbitrary levels. For example, I'd like to be  
> able to do the following:
> 
>    1 2 3 + [[dup] first] [swap] first 5 2 +
>    1 2 3 + [`dup] [swap] first 5 2 +
>    1 2 3 + [`dup] [swap] first 7
>    1 2 3 + [`dup] `swap 7
>    1 5 [`dup] `swap 7
> 
> This is not possible if you use an explicit stack/queue for your  
> reduction. You need to make sure each step in the reduction is itself  
> a valid program.

sure.  but `dup is just notation.  it's a method of recording that dup
has changed its role in the reduction.

> 
> - John
>