> On Feb 17, 2025, at 3:08 PM, Van Snyder <van.sny...@sbcglobal.net> wrote:
>
> On Mon, 2025-02-17 at 09:13 -0500, Paul Koning wrote:
>>
>>>
>>> When Tom Pennello was a grad student studying under Frank de Remer at
>>> ACSC, he collected a big pile of codes in languages that had nested
>>> lexical and dynamic scopes (such as recursive internal functions). He
>>> found that chasing up-links was much faster than displays. In some
>>> cases, creating and destroying the display took six times longer than
>>> executing the function. I mentioned this to Malcolm Cohen and me
>>> mumbled something about a "trampoline." I have no idea what that is.
>>
>> I'm puzzled by that, since the display is a static data structure and
>> updating it takes only a few instructions for each call and fewer for a
>> return.
>
> The display isn't static for nested recursive functions (as in Pascal) and
> you want to have "deep binding," not "shallow binding."
I meant static as in allocation, not content. Yes, it changes for every call,
but that change is only 2 or 3 instructions.
paul
