Forum: Ruby-core [ruby-trunk - Feature #7322][Open] Add a new operator name #>< for bit-wise "exclusive or"

Issue #7322 has been reported by alexeymuranov (Alexey Muranov).

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322

Author: alexeymuranov (Alexey Muranov)
Status: Open
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

> "a^n" usually means "the n-th power of a"

I agree, I think using "^" for exponents would be more consistent with
other languages. I don't have a strong opinion on a replacement for
'exclusive or', but some other approximations of "⊻"  could be: "|<" or
"/<".

Issue #7322 has been updated by alexeymuranov (Alexey Muranov).


Related: #6678.
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32817

Author: alexeymuranov (Alexey Muranov)
Status: Open
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


Given the rejection of #7336, I would ask this this issue be more 
seriously considered. Personally, I don't really care if #^ continues to 
mean bitwise xor for numerics, but at least raise its precedence to be 
the same as #**, and provide an alternative xor operator with the 
present precedence. Whether `#><` is a good choice or not, I am mostly 
indifferent. (I suppose alternatives might be `#~` or `#!` which are 
unary operators, but have no binary definition.)

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32936

Author: alexeymuranov (Alexey Muranov)
Status: Open
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by matz (Yukihiro Matsumoto).

Status changed from Open to Rejected

So what's your intention?  To make '^' a power operator, and ruin 
innocent programs? Because you feel "natural"?
If Ruby were young and there were no (or few) Ruby programs out there, 
your proposal might be useful.
But I don't want to break compatibility for fashion.
"When in Rome, do as the Romans do".

Matz.

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32945

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by david_macmahon (David MacMahon).


I fully agree that repurposing '^' to be a power operator is not a good 
idea.

One alternative idea that might not make anyone happy would be to create 
a new power operator "^^" that is the same as "**", but seems more like 
exponentiation to those too young to know (or too old to remember :-)) 
Fortran.

Please feel free to ignore this suggestion,
Dave

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32946

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


@matz Have you ever read about issue I have with implementing Stick b/c 
of this? I have no Rome to be in. I am in Carthage!

@dvaid_macmahon Well, #^^ would be better than nothing.

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32948

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by matz (Yukihiro Matsumoto).


No. There are so many "issues" out there. I don't have time to check 
them all.
Reference please.

Matz.

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32949

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by alexeymuranov (Alexey Muranov).


Speaking of Fortran, there the binary `*` has higher precedence than the 
unary `-`, which has approximately the same as the binary one.  (This is 
not about this issue, but about #7328 and #7331.)

I would way it is unfortunate that the main reason to reject it that 
Ruby is too old to change.  (The changes would not need to be immediate, 
i think that aliases can be introduced or deprecated between major 
versions.)  But i am not a heavy Ruby user, i was only proposing my 
ideas hoping that they could be useful for others too.
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32963

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


=begin
@matz

Reference given below[1], but I can give very brief summary to save you 
time...

Stick is an SI units system for Ruby. While in pure math there is just 
one type of "power" (in Ruby provided by (({#**}))), in physical systems 
there is also units and units themselves can have "power", e.g. cubic 
meters. So any good units system therefore ((*needs two power 
operators*)), one for the value and one for the unit. The natural 
notation for these are, e.g.

    10.m**3   (10 meters * 10 meters * 10 meters)
    10.m^3    (10 cubic meters)

But precedence of (({#^})) is too low in Ruby to do this well, e.g.

    10.m^2/2  => 10 meters, instead of 5.m^2

Nor is there some alternative operator to utilize.

Unit powers is a common real word application, so I think it is not 
unreasonable to seek that Ruby be able to accommodate such a use case.

In short, for me to create the best SI units system I can for Ruby, I 
need another power operator.

[1] 
https://github.com/trans/trans.github.com/wiki/200...
=end

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32975

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by stomar (Marcus Stollsteimer).


@trans

There is only one type of power operator in physics.
You would have to use parentheses:

  (10 m)^3   (10 meters * 10 meters * 10 meters)
  10 m^3     (10 cubic meters)

And I think you should also have to use them in the code.

From a physicist's point of view, I find the idea of distinguishing 
between different kinds of power operators strange at best, probably 
confusing to the user and maybe even dangerous.

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32983

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by alexeymuranov (Alexey Muranov).


Thomas, i agree with @stomar.
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32986

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


=begin
@stomer

Yes and no. The problem is in the Ruby notation. In physics, you can use 
parenthesis to make the distinction, but you can't in Ruby. e.g. Your 
example doesn't work in Ruby:

  10.m**3

and

  (10.m)**3

Can only produce the same result.
=end

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32987

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Sorry, I didn't read the whole thread, but why not use the right 
operators?

    g = 9.81 * m / s ** 2

Issue #7322 has been updated by stomar (Marcus Stollsteimer).


=begin
@trans

Imo the point is that using a method for the unit does not correctly 
model the mathematical relation (and hence the precedence) between the 
numerical value of the physical quantity and its unit, which simply is a 
multiplication.

Just a thought: how about using an argument for the power of the unit, 
like in

  10.m**3  # (10 m)^3
  10.m(3)  # 10 m^3

But this is taking a very off-topic direction...
=end

----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-32989

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


=begin
It might seem like it, but designating a unit is not multiplication.

(({9.81 * m})) actually means (({9.81 * 1 m}))

Implementation wise this approach is a bit messier too. It requires 
overriding the built-in #* method and adding a slew of type methods to 
Object (e.g. Object#m).

@stomer Using an argument for the unit power isn't a skeuomorphic ideal. 
But it might suffice. I need to give it some thought and take a look at 
the Stick code to make sure. I'll try to do that today and report back. 
Thanks.

Speaking of a skeuomorphic ideal, do you notice that in general contexts 
when people give ascii examples of "power" they always use (({^}))? I 
don't really understand why language designers are so bent on bucking 
the overwhelming commonality of this choice --all solely to cling to C's 
tradition of using (({^})) as XOR? How unfortunate. But anyway, I 
digress.
=end
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-33012

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by trans (Thomas Sawyer).


Hmm... "skeuomorphic" probably isn't really the right word actually. I 
really meant something more like "reflecting reality". In this case, 
specifically, "best reflecting common mathematical notation".
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-33013

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end

Issue #7322 has been updated by alexeymuranov (Alexey Muranov).


Thomas, let some physicist correct me, but i thought that designating 
units was multiplication: 9.81 m/s^2 = (9.81 * m)/(s^2).  This should 
however be discussed in a different thread. :)
----------------------------------------
Feature #7322: Add a new operator name  #><  for bit-wise "exclusive or"
https://bugs.ruby-lang.org/issues/7322#change-33017

Author: alexeymuranov (Alexey Muranov)
Status: Rejected
Priority: Low
Assignee:
Category:
Target version:


=begin
I propose to alias (({Fixnum#^})) and (({Bignum#^})), which stand for 
bit-wise "exclusive or", with a new operator name (({#><})).

Is it necessary to go along with C, Python, and Mathematica?
According to Wikipedia ( 
http://en.wikipedia.org/wiki/Exclusive_or#Alternat... ), the "^" 
symbol is not used for XOR outside of programming context.

Here are some examples of mathematical notation: 
http://mathworld.wolfram.com/XOR.html (there are also examples in the 
Wikipedia article).

The Unicode symbol is "⊻".

If eventually (({Fixnum#^})) as XOR is deprecated, this will liberate 
this symbol for other uses, for example for all kinds of exponential 
notations (for me, "a^n" usually means "the n-th power of a").
=end