r3wp [groups: 83 posts: 189283]
  • Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search
 

World: r3wp

[!REBOL3]

Ladislav
19-Apr-2011
[8033x2]
To complete the informations, I should probably perform a user poll 
in here. So, here goes:


*For me, one of the main goal of logic operators like NOT, AND, OR, 
XOR is to yield a value, that is used mainly as the CONDITION argument 
of the IF, UNLESS, EITHER, etc. control functions.


*Taking NOT (which is a unary logic operator) as an example, we see, 
that it is compatible with the above mentioned main purpose. The 
goal is achieved by "delegating" other functionalities NOT does not 
perform to COMPLEMENT. It is not possible for NOT to be both compatible 
with IF and perform the operations COMPLEMENT does.


*Taking OR (which is a binary logic operator) as an example, we see, 
that it is incompatible with the above mentioned main purpose, not 
being able to correctly handle some logic combinations, that would 
be compatible with IF. As an example, see the expression
    0 or true

, which cannot be used to yield an argument for IF, although both 
its arguments *are* compatible with IF. Interestingly, there is not 
a shortage of functions that are meant to perform analogical non-logic 
operations. I would like to specifically mention the UNION function, 
which seems to be related to OR similarly as COMPLEMENT is related 
to NOT.

*The question I am asking you is:

- Do you prefer the "logical" solution used in the case of NOT, and 
apply it to other operators like AND and OR as well, or

- Do you prefer the "non-logical" solution used in case of AND and 
OR and apply it to the NOT operator as well, or
- Do you prefer to keep the current state of affairs for R3?
I am for the first alternative, letting AND, OR and XOR work as "logic" 
operators only, "delegating" other (similar) functionalities to functions 
like UNION, INTERSECT, etc.
Maxim
19-Apr-2011
[8035]
+ 1
Gregg
19-Apr-2011
[8036]
I misunderstood as well. Thanks for clarifying.

+1 for having AND, OR, and XOR work as logic ops only.
Geomol
19-Apr-2011
[8037]
I can see, how it became this way trying to avoid &, | and ^ for 
AND, OR and XOR.
BrianH
19-Apr-2011
[8038]
The main reason the logic operators don't support none is to cut 
down on none propagation. We want those errors triggered, not unintentionally 
ignored.
Ladislav
19-Apr-2011
[8039]
So, which variant do you prefer?
BrianH
19-Apr-2011
[8040]
I don't mind AND, OR and XOR being both logical and bitwise ops. 
If there is a problem with the current behavior, I don't remember 
being tripped up by it.
Ladislav
19-Apr-2011
[8041]
There surely is a problem, why would NOT be implemented differently 
otherwise?
Geomol
19-Apr-2011
[8042]
Atm. I prefer the same as you too (the first one), but I would suggest 
some names for the bitwise and, or and xor in the reporting of this.

I feel, the language would benefit from being a bit more strict.
Maxim
19-Apr-2011
[8043]
I'm tripped by it EVERYTIME I try to use them... none is a valid 
value for all logic control funcs.


so in over 10 years of reboling I've never been able to use them 
to control logic flow... I've used them only as bitwise ops...
Ladislav
19-Apr-2011
[8044]
Yes, Max, I guess, that you are not an exception
BrianH
19-Apr-2011
[8045]
NOT is an action that generates a logic! value. I like the current 
Lisp-like treatment, having none and false being falsey values and 
everything else being truthy values, with explicit conversions already 
available if we need them. Whatever we do, please don't have zero 
values be false without explicit conversion.
Geomol
19-Apr-2011
[8046]
I think, Carl deside these thing by trying to figure out, what makes 
most sense for a new one to programming. Or trying to make a more 
humane less computer technical language.
Maxim
19-Apr-2011
[8047]
(funny thing is that I keep forgetting this detail , and every few 
months I loose an hour trying to debug code until I remember ... 
hehe)
Gregg
19-Apr-2011
[8048x2]
I also only use them as bitwise ops, but I don't remember tripping 
over it very often. I just always use ANY and ALL. NOT was probably 
designed to be friendly, rather than pure, and I do use it a lot.
John, yes, and also supporting things people expect when coming from 
other languages.
BrianH
19-Apr-2011
[8050x2]
I come from languages that either have an explicit boolean type (Pascal-like) 
or act like REBOL (Lisp-like and Smalltalk-like).
C-like languages always trip me up - a mass of design flaws, the 
whole lot of them.
Ladislav
19-Apr-2011
[8052]
Well, but, in this case, C works better by discerning | and ||
BrianH
19-Apr-2011
[8053]
The thing is, C needs to because it doesn't have proper boolean types, 
and REBOL doesn't need to because it has the logic! type.
Geomol
19-Apr-2011
[8054]
Maybe AND, OR and XOR should only be bitwise, and then introduce 
&& and || (and maybe logical xor ^^, but just maybe).
Ladislav
19-Apr-2011
[8055]
REBOL needs to as well, since it (IF, UNLESS, EITHER, etc.) implements 
anything as logic, in fact.
BrianH
19-Apr-2011
[8056]
We can do explicit conversions, and our code becomes easier to understand 
as a result.
Maxim
19-Apr-2011
[8057]
but brian, we cannot use AND/OR for logic comparisons...  #[none] 
breaks them and none *IS* a valid conditional value.
Gregg
19-Apr-2011
[8058]
&& and ||  -- Please NOOOOOOOOO!
Geomol
19-Apr-2011
[8059]
:-D
Gregg
19-Apr-2011
[8060]
:-)
Geomol
19-Apr-2011
[8061]
Yeah, they're ugly!
Maxim
19-Apr-2011
[8062x2]
well, then we should remove   / * - + ^ too.
:-)
Gregg
19-Apr-2011
[8064]
Just vote on Ladislav's proposal, and we'll see where the results 
lead.
Geomol
19-Apr-2011
[8065x2]
But if almost nobody use OR today as logical or, but do as bitwise 
or, then we shouldn't change that.
LOR, LAND and LXOR
;p
Gregg
19-Apr-2011
[8067]
If our goal is not to break things, yes. If our goal is to clean 
things up for the long term, now is the time.
BrianH
19-Apr-2011
[8068]
None is a falsey value (NOT the value returns true), but not a false 
value. If we want to have AND, OR and XOR accept none as a false 
value, this will lead to errors being ignored unintentionally. We 
can do it, but there is a drawback. Still, I prefer that to making 
a separate set of operators for bitwise operations.
Gregg
19-Apr-2011
[8069]
Some languages do that, but usually the other way around (bit-and, 
bit-or, ...).
Geomol
19-Apr-2011
[8070]
How would you split OR into two, Gregg?
Maxim
19-Apr-2011
[8071]
I find that R3 is the right time to address these issues in the language.


R3 is already incompatible.  I don't see a reason not to clean this 
up.
Gregg
19-Apr-2011
[8072x2]
John: O and R. ;-)
It's funny, though, talking about logic values and then having "falsey" 
and "truthy" values.
Geomol
19-Apr-2011
[8074]
So it'll go like: Hey Carl, we've found this huge problem ... and 
we have no solution.

Poor Carl.
BrianH
19-Apr-2011
[8075]
I always use AND, OR and XOR in both their logical and bitwise sense. 
There is no confusion because I have to use logic! values for the 
logical behavior. This means that explicit conversions resolve the 
difference visibly.
Maxim
19-Apr-2011
[8076]
but brian, the current AND/OR/XOR  *cannot* be used for logical ops. 
 the fact that none isnt' supported is the proof that its not working. 
  bitwise ops already exist in principle with the "set" functions 
 'complement, 'union etc.
Gregg
19-Apr-2011
[8077]
Bitwise ops are computerish, logical ops are how humans think. I 
don't mind making the bitwise alternatives a little more verbose, 
or even adding a dialected BITWISE function.
BrianH
19-Apr-2011
[8078]
I use the term "conditional expressions" for the truthy/falsey expressions, 
and "logical expressions" for the logic!-only ones, not interchangeably.
Gregg
19-Apr-2011
[8079x2]
But, as Max brought up again, teh set ops are already there.
Ah, I see Brian. I'll try to remember that.
BrianH
19-Apr-2011
[8081]
TRUE? was designed to convert a conditional expression to a logical 
expression. I think it used to say that in its docstring.
Gregg
19-Apr-2011
[8082]
Anyway, vote on Ladislav's proposal. I'm a +1.