Hi Chris,
On Fri, 2 Nov 2018 07:44:00 -0700, Chris Cunningham cunningham.cb@gmail.com wrote:
ParcPlace-Digitalk VSE 3.1 (roughly 1999):
(0 to: 1) = (0 to: 5/3). "true" (0 to: 1) hash = (0 to: 5/3) hash. "true"
So, ancient VSE and current VisualWorks are consistent, and agree on where they want to be. This is also the direction I want to take Squeak. VA is also consistent, but #= doesn't match any other Smalltalk varient that we've looked at. Squeak, Pharo, Dolphin all currently have the same answer, but are not consistent.
Interesting indeed.
I have been talking to the VA Smalltalk guys about this and they are thinking about it but haven't decided what to do yet. It turns out that the way collections (like Set) that use #hash in VA Smalltalk work, because of the #= test failing for intervals that cover the same range and have the same hash, that it overrides the equal hash value and adds the interval to the collection. I find this troubling.
Lou
thanks, cbc
On Thu, Nov 1, 2018 at 5:40 AM Louis LaBrunda Lou@keystone-software.com wrote:
Hi Benoit,
On the latest version of VA Smalltalk:
VA Smalltalk V9.1 (32-bit); Image: 9.1 [413] VM Timestamp: 4.0, 10/01/18 (100)
I see:
(0 to: 1) = (0 to: 5/3). "false" (0 to: 1) hash = (0 to: 5/3) hash. "true"
Very interesting.
Lou
On Thu, 1 Nov 2018 02:40:00 +0000 (UTC), Benoit St-Jean via Squeak-dev < squeak-dev@lists.squeakfoundation.org> wrote:
Interesting!
As a comparison: Squeak 5.2 (0 to: 1) = (0 to: 5/3). "true"(0 to: 1) hash = (0 to: 5/3) hash. "false" Dolphin 7(0 to: 1) = (0 to: 5/3). "true"(0 to: 1) hash = (0 to: 5/3)
hash. "false"
VisualWorks 8.1.1(0 to: 1) = (0 to: 5/3). "true" (0 to: 1) hash = (0 to: 5/3) hash. "true" Pharo 5.0(0 to: 1) = (0 to: 5/3). "true" (0 to: 1) hash = (0 to: 5/3) hash. "false"
I don't have VAST installed on the PC I'm using right now. I'd be
curious to see how other Smalltalk and/or GemStone handle this? So far (according to what I could test, only VW is right (according to the ANSI standard and just plain logic!)
I wonder how much code relies on this "behavior" out there! But the ANSI Smalltalk draft is very clear on this (revision 1.9, page
53, http://wiki.squeak.org/squeak/uploads/172/standard_v1_9-indexed.pdf):
"If the value of receiver = comparand is true then the receiver and
comparand *must* have equivalent hash values."
That's what I always thought (or was taught or even read in the Blue
Book). Was this something that was changed at some point???
BenoƮt St-Jean Yahoo! Messenger: bstjean Twitter: @BenLeChialeux Pinterest: benoitstjean Instagram: Chef_Benito IRC: lamneth Blogue: endormitoire.wordpress.com "A standpoint is an intellectual horizon of radius zero". (A. Einstein)
-- Louis LaBrunda Keystone Software Corp. SkypeMe callto://PhotonDemon