AltME: REBOL3

Messages

PeterWood
I suppose same? could provide the actual check that the values are actually equal but it doesn't seem to in Rebol2
>> same? 0.1 + 0.1 + 0.1 3
== false
>> same? 0.49999999999999994 0.5
== true
Typo:
>>  same? 0.1 + 0.1 + 0.1 0.3
== true
Ladislav
Hi, I corrected the AE? function at https://github.com/rebol/rebol-issues/issues/2259 (there were some bugs) and improved comments.
PeterWood
I see that same? works as I expected in Rebol 3:
>> same? 0.49999999999999994 0.5
== false
>> same? 0.1 + 0.1 + 0.1 0.3
== false
Ladislav
Yes, Peter
PeterWood
So my thought that strict-equal? should check for the values being the same is probably not necessary.
Ladislav
examples:
>> ae? 0.49999999999999994 0.5
== true
>> ae? 0.1 + 0.1 + 0.1 0.3
== true
However, AE? is transitive, and (while only exceptionally), sometimes you get FALSE from AE? A B even when A and B differ only by one ULP. This is inevitable for a transitive relation.
(I should have said: this is inevitable for a nontrivial transitive relation)
PeterWood
That seems very reasonable.
Ladislav
At present, there is only one difference between SAME? and STRICT-EQUAL? for decimals in Rebol3. It is this one:
>> strict-equal? 0.0 -0.0
== true
>> same? 0.0 -0.0
== false
The difference is caused by the fact that 0.0 and -0.0 have different binary representations.
>> to binary! 0.0
== #{0000000000000000}
>> to binary! -0.0
== #{8000000000000000}
PeterWood
So strict-equal? is more strict in R3 than R2.
Ladislav
Yes
PeterWood
That's good.

Ladislav
Hi all, as far as I know, Rebol is considered a high-level cross-platform language. For example, in Windows and in all GCC-compiled platforms it uses two's complement signed integers. I think that to be truly cross-platform, it should use two's complement signed integers on every platform. What do others think on this?
Ladislav
Note: currently, the two's complement signed integer representation is already tested by the core-tests, otherwise it is not enforced.

Ladislav
Please check the ~Humour (my apologies for misusing the group) and #Topaz for the discussion/poll related to undefined variables, #[datatype! unset!], etc.

Arnold
@Reichart Will R4 be open sourced? I have PM ed with Bo about what I thought has to be done about R3.
As well Carl and Earl do not attend to the R3 repo so something has to be done.

Last message posted 165 weeks ago.