Re: [stack] sweetening concatenative syntax

On Mar 8, 2008, at 19:06 , [email protected] wrote:

> On Sat, March 8, 2008 2:58 pm, Don Groves wrote:
>
>> My understanding of linearity is that a value have only a single
>> reference at any one instant.
>
> Right.
>
>> So, for example, if a value is pushed on the stack, it may not be  
>> held
>> anywhere else simultaneously as it is now referenced by the stack.
>
> Right.
>
>> This seems to rule out the possibility of pushing a variable's
>> value onto the stack, then doing it again later from the same  
>> variable.
>
> There's no variable to push "from". Lambda expressions are  
> translated to
> pointfree stack-based code. If a variable is used more than once,  
> explicit
> copying is automatically inserted as I described earlier.

OK, thanks. The same thing happens in ACL, my as yet unfledged
contribution to the cause. Explicit copying allows you to immediately
free memory when a stack item is consumed, hence there's no way
a value can have multiple references.
--
don




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