Date: Thu, 09 Dec 1999 22:34:11 +0100 From: Roelof Osinga <roelof@nisser.com> To: David Scheidt <dscheidt@enteract.com> Cc: Brett Glass <brett@lariat.org>, Tani Hosokawa <unknown@riverstyx.net>, Jonathon McKitrick <jcm@dogma.freebsd-uk.eu.org>, Alfred Perlstein <bright@wintelcom.net>, Kris Kennaway <kris@hub.freebsd.org>, freebsd-chat <chat@FreeBSD.ORG> Subject: Re: Yahoo hacked last night Message-ID: <38502053.28737F7B@nisser.com> References: <Pine.NEB.3.96.991208230511.72276B-100000@shell-3.enteract.com>
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David Scheidt wrote: > > I learned it in the context of functional languages which do > lazy-evaluation. A function call didn't need to return the actual result of > the function, but rather just a promise that the result would be evaluated > in the future, but only if the result were really needed for something. For > all intents, the thunk returned could be used in any way that the actual > result could. So it is easy to right an O(1) function to find the Nth digit > of Pi. Printing your result, though, could take a really long time. Why the past tense? I "recently" implemented one. Unfortunately I wrote it in Smalltalk on OS/2 (Digitalk's V/PM) so it has been sort of neglected since I moved away from that platform. You're right that they're inherently slow. OTOH they lend themselves quite well to automatic transformations and thus optimizations. Not the least of which is detecting when strict evaluation can be used. But their type correctness makes up for a lot. Will prevent a lot of errors and thus save a lot of time. With the continued increase in clock speed and RAM they could have a very good future ahead of them. Roelof -- Home is where the (@) http://eboa.com/ is. Telekabel home http://nisser.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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