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World: r3wp

[!REBOL3 Proposals] For discussion of feature proposals

Andreas
20-Jan-2011
[694x2]
Either in the default case, or with a /case, /strict or /whatever 
refinement.
Framed this way, this discussion would be a lot easier, imo; and 
probably more fruitful.
BrianH
20-Jan-2011
[696]
That is a seperate issue that needs its own ticket. FIND and SELECT 
use their own code, so they can only follow the same rules, not use 
the same code.
Andreas
20-Jan-2011
[697]
That is an implementation problem, not a design issue
BrianH
20-Jan-2011
[698]
I am OK with a DAG for the equivalences, but would prefer the exact 
decimal comparison to go in the EQUIV?, STRICT-EQUIV? branch.
Andreas
20-Jan-2011
[699x2]
Fine with me, but most likely only a minor issue.
For reference, also be aware that we have operator shortcuts for 
the comparison functions. At the moment:
=: equal? (and !=
==: strict-equal? (and !==)
=?: same?


The == operators should then probably become shortcuts for strict-equiv.
BrianH
20-Jan-2011
[701]
That's a bigger problem than binding, believe me. Exact decimal comparison 
makes floating point code nearly unusable by normal programmers.
Andreas
20-Jan-2011
[702x2]
As mentioned above, that's perfectly fine with me.
It's not decimal precision which makes the FIND (and STRICT-MAP!) 
discussion so cumbersome.
BrianH
20-Jan-2011
[704x3]
We don't need operators for the equiv branch. STRICT-EQUIV? and SAME? 
are the same thing for words and decimals.
If you want I can write up your reshuffled hierarchy as a CC ticket. 
I think Carl would like it, ans the binding issue has bit him in 
the past.
ans -> as
Andreas
20-Jan-2011
[707x2]
Thanks for your input. I'll also wait for Ladislav's input at least, 
as the "Comparisons" doc was authored by him.
So let's update this with the decimal precision moved:

- equal?
- strict-equal?: equal + type + case + alias

- equiv?: equal + binding + decimal 
- strict-equiv?: equiv + type + case + alias

- same?: as currently
BrianH
20-Jan-2011
[709x2]
Strangely enough, it's not binding or exact decimal comparison that 
are at issue with FIND or strict-map! either, it's case and type. 
Nonetheless, this would make it easier to point to the distinction 
between STRICT-EQUAL? and STRICT-EQUIV? when talking about those, 
precisely because those aren't at issue.
Sounds good to me.
Andreas
20-Jan-2011
[711]
As you see, case and type are the major distinction between equal 
and strict-equal.
BrianH
20-Jan-2011
[712]
Yup. That makes sense.
Andreas
20-Jan-2011
[713x2]
So that would make it easy to define FIND as using EQUAL? per default, 
and STRICT-EQUAL? with /case.
(Or a renamed /case option. A bit hypothetical due to backwards compatibility, 
but mentioning it for the sake of completeness.)
BrianH
20-Jan-2011
[715x2]
We can't rename the /case option - legacy naming rules. And if the 
equivalences are reshuffled this way, we won't have to.
Andreas, the proposal has been added here: http://issue.cc/r3/1834
- if you have any suggestions or tweaks, mention them here or there 
and I'll update it.
Andreas
20-Jan-2011
[717x2]
Yes, I have a suggestion: my explicit wish was to wait with this 
for Ladislav's feedback.
Please respect that in the future.
BrianH
20-Jan-2011
[719x2]
I put in a request for Ladislav's feedback in a ticket comment, and 
in other AltME worlds where he works. Including the RMA world, where 
they write code that would be affected by this.
Unlike here, tickets can be tweaked based on feedback. We needed 
a baseline to start with.
Andreas
20-Jan-2011
[721x2]
Unlike here, extensive CC discussions are a mess.
Edit "no aliasing" to "alias distinctions". Thanks.
BrianH
20-Jan-2011
[723x2]
They're a mess here too, but are more useless because they can't 
be searched as easily once they drop off the history, and the relevant 
people who would make the changes aren't generally here that much.. 
CC is a much better place for this kind of thing.
Actually, no aliasing is more correct than what is on the wiki.
Andreas
20-Jan-2011
[725x2]
equal plus no aliasing
 is bad wording.
And it's really simple: I wanted Ladislav's feedback here first, 
before we write up a ticket and litter it with useless comments. 
Again, please respect that in the future.
BrianH
20-Jan-2011
[727x2]
OK.
Case-insensitivity is implemented using aliasing. Case sensitivity 
means that the aliases are ignored - no aliasing.
Andreas
20-Jan-2011
[729x5]
Case sensitivity does not mean that aliases are ignore.
At least I don't know of a way off hand to prove that.
But I trust you that word case sensitivity is implemented using aliases.
But to me, "equal plus no aliasing" still does not clearly express 
whether aliased words are considered to be equal or ignored in this 
case.
equal or different*
BrianH
20-Jan-2011
[734]
Fortunately it can be edited (and I will do that now).
Andreas
20-Jan-2011
[735x2]
Equal plus alias distinction
 was clearer to me.
(As not all aliases are case related.)
BrianH
20-Jan-2011
[737]
Actually, that feature might go away. The ALIAS function has been 
a big hassle in R3 because of the lack of a central system/words 
repository. We are likely to keep the aliasing facility for internal 
use to implement case insensitivity, but the ALIAS function to do 
other kinds of aliasing may go away.
Andreas
20-Jan-2011
[738]
Yes, I am aware of that.
BrianH
20-Jan-2011
[739]
Oh good :)
Andreas
20-Jan-2011
[740]
But as of A110, we still have it  :) So to formulate the wish on 
that basis, we need to take it into account, or someone else will 
hassle us about having left out alias.
BrianH
20-Jan-2011
[741]
Yup. Working on the wording now. I think the semantics of the proposal 
are good though.
Andreas
20-Jan-2011
[742]
Just keep it short, though.
Ladislav
20-Jan-2011
[743]
>> equal? -0. 0.
== true

>> equiv? -0. 0.
== true

>> strict-equal? -0. 0.
== true

>> same? -0. 0.
== false