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Re: -2 ** 2

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  Re: -2 ** 2 Jon Ribbens <jon+usenet@unequivocal.eu> - 2017-05-04 14:13 +0000
    Re: -2 ** 2 Tim Streater <timstreater@greenbee.net> - 2017-05-04 16:56 +0100
      Re: -2 ** 2 Mark Lloyd <not@mail.invalid> - 2017-05-04 12:08 -0500
      Re: -2 ** 2 John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-04 20:02 +0100
      Re: -2 ** 2 Jon Ribbens <jon+usenet@unequivocal.eu> - 2017-05-04 23:44 +0000
        Re: -2 ** 2 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-05-05 09:16 +0200
          Re: -2 ** 2 John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-05 09:56 +0100
            Re: -2 ** 2 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-05-05 11:16 +0200
              Re: -2 ** 2 John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-06 10:27 +0100
                Re: -2 ** 2 "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2017-05-06 11:42 +0200
    Re: -2 ** 2 Robert Heller <heller@deepsoft.com> - 2017-05-04 11:01 -0500
    Re: -2 ** 2 Sam E <why.should.this@be.email.invalid> - 2017-05-04 12:04 -0500
      Re: -2 ** 2 John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-04 19:29 +0100
        Re: -2 ** 2 Tim Streater <timstreater@greenbee.net> - 2017-05-04 19:51 +0100
          Re: -2 ** 2 John G Harris <niam@jghnorth.org.uk.invalid> - 2017-05-05 09:41 +0100
          Re: -2 ** 2 Tim Slattery <tim@risingdove.com> - 2017-05-05 11:02 -0400
            Re: -2 ** 2 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-05 17:47 +0200
            Re: -2 ** 2 Tim Streater <timstreater@greenbee.net> - 2017-05-05 16:49 +0100
              Re: -2 ** 2 Tim Slattery <tim@risingdove.com> - 2017-05-06 11:21 -0400
                Re: -2 ** 2 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-06 19:04 +0200
                  Re: -2 ** 2 Tim Slattery <tim@risingdove.com> - 2017-05-07 12:40 -0400
                    Re: -2 ** 2 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-07 20:35 +0200
                  Re: -2 ** 2 RobG <rgqld@iinet.net.au> - 2017-05-10 17:46 -0700
                    Re: -2 ** 2 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-11 03:00 +0200
            Re: -2 ** 2 Mark Lloyd <not@mail.invalid> - 2017-05-05 23:20 -0500
            Re: -2 ** 2 Dr J R Stockton <reply1700@merlyn.demon.co.uk.invalid> - 2017-05-08 23:19 +0100
        Re: -2 ** 2 Dr J R Stockton <reply1700@merlyn.demon.co.uk.invalid> - 2017-05-08 23:16 +0100
          Re: -2 ** 2 "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-05-09 09:55 -0700
          Re: -2 ** 2 Dr J R Stockton <reply1700@merlyn.demon.co.uk.invalid> - 2017-05-10 17:39 +0100
            Re: -2 ** 2 Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-05-11 03:08 +0200

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#33194 — Re: -2 ** 2

On 2017-05-04, Stefan Ram <ram@zedat.fu-berlin.de> wrote:
>   In a recent Firefox:
>
> -2 ** 2
>
> SyntaxError: unparenthesized unary expression can't appear on
> the left-hand side of '**'
>
>   . Can't seem to find the corresponding rule in a recent copy
>   of ECMAScript (12.6), though.

Chrome behaves similarly:

  -2 ** 2
  Uncaught SyntaxError: Unexpected token **
  (-2) ** 2
  4

Presumably this is a sensible thing to avoid bugs, e.g. Python does
this:

  >>> -2**2
  -4
  >>> (-2)**2
  4

I think most people would expect both expressions to equal 4.

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#33196

In article <slrnogmdu6.50n.jon+usenet@sable.unequivocal.eu>, Jon
Ribbens <jon+usenet@unequivocal.eu> wrote:

>On 2017-05-04, Stefan Ram <ram@zedat.fu-berlin.de> wrote:
>>   In a recent Firefox:
>>
>> -2 ** 2
>>
>> SyntaxError: unparenthesized unary expression can't appear on
>> the left-hand side of '**'
>>
>>   . Can't seem to find the corresponding rule in a recent copy
>>   of ECMAScript (12.6), though.
>
>Chrome behaves similarly:
>
>  -2 ** 2
>  Uncaught SyntaxError: Unexpected token **
>  (-2) ** 2
>  4
>
>Presumably this is a sensible thing to avoid bugs, e.g. Python does
>this:
>
>  >>> -2**2
>  -4
>  >>> (-2)**2
>  4
>
>I think most people would expect both expressions to equal 4.

Depends on operator precedence.

-- 
"If you're not able to ask questions and deal with the answers without feeling 
that someone has called your intelligence or competence into question, don't 
ask questions on Usenet where the answers won't be carefully tailored to avoid
tripping your hair-trigger insecurities."                  - D M Procida, UCSM

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#33199

On 05/04/2017 10:56 AM, Tim Streater wrote:
> In article <slrnogmdu6.50n.jon+usenet@sable.unequivocal.eu>, Jon
> Ribbens <jon+usenet@unequivocal.eu> wrote:
>


[snip]

>>  >>> -2**2
>>  -4
>>  >>> (-2)**2
>>  4
>>
>> I think most people would expect both expressions to equal 4.
>
> Depends on operator precedence.
>

I was always taught "Especially My Dear Aunt Sally" to remember the 
order of precedence, although I never needed it (understanding works 
better). Exponentiation has higher precedence that subtraction.

What actually happens depends of whether '-' is recognized as 
subtraction or the unary operator (I'd expect subtraction). Anyway, to 
avoid problems I's use parentheses.

-- 
Mark Lloyd
http://notstupid.us/

"SENILE.COM found. Out Of Memory."

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#33202

On Thu, 04 May 2017 16:56:06 +0100, Tim Streater
<timstreater@greenbee.net> wrote:

>In article <slrnogmdu6.50n.jon+usenet@sable.unequivocal.eu>, Jon
>Ribbens <jon+usenet@unequivocal.eu> wrote:
>
>>On 2017-05-04, Stefan Ram <ram@zedat.fu-berlin.de> wrote:
>>>   In a recent Firefox:
>>>
>>> -2 ** 2
>>>
>>> SyntaxError: unparenthesized unary expression can't appear on
>>> the left-hand side of '**'
>>>
>>>   . Can't seem to find the corresponding rule in a recent copy
>>>   of ECMAScript (12.6), though.
  <snip>

See sections 12.4, 12.5, 12.6 of the Standard. You can't have 
  -x ** y
because a unary minus can't act on an exponentiation expression.


>Depends on operator precedence.

Like some similar languages, ECMAScript doesn't specify operator
precedence; it's the production rules in the syntax specification that
decide how an expression is to be interpreted.

  John

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#33203

On 2017-05-04, Tim Streater <timstreater@greenbee.net> wrote:
> In article <slrnogmdu6.50n.jon+usenet@sable.unequivocal.eu>, Jon
> Ribbens <jon+usenet@unequivocal.eu> wrote:
>>Presumably this is a sensible thing to avoid bugs, e.g. Python does
>>this:
>>
>>  >>> -2**2
>>  -4
>>  >>> (-2)**2
>>  4
>>
>>I think most people would expect both expressions to equal 4.
>
> Depends on operator precedence.

You don't say. It's almost as if that was the very subject of my post
that you are replying to.

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#33208

Jon Ribbens <jon+usenet@unequivocal.eu> wrote on 05 May 2017 in 
comp.lang.javascript:

> On 2017-05-04, Tim Streater <timstreater@greenbee.net> wrote:
>> In article <slrnogmdu6.50n.jon+usenet@sable.unequivocal.eu>, Jon
>> Ribbens <jon+usenet@unequivocal.eu> wrote:
>>>Presumably this is a sensible thing to avoid bugs, e.g. Python does
>>>this:
>>>
>>>  >>> -2**2
>>>  -4
>>>  >>> (-2)**2
>>>  4
>>>
>>>I think most people would expect both expressions to equal 4.
>>
>> Depends on operator precedence.
> 
> You don't say. It's almost as if that was the very subject of my post
> that you are replying to.

True.

Even so, it seems that the way the minus sign is parsed,
the unary behavour is unnoticed in this case 
by the parsing engine [back to js, please]:

let  r1 = -2 ^ 2; // -2

... even if it is just unforgivable as in:

let  r2 = 0 + -2 ^ 2; // -2

-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#33211

On Fri, 05 May 2017 09:16:13 +0200, "Evertjan."
<exxjxw.hannivoort@inter.nl.net> wrote:

  <snip>
>Even so, it seems that the way the minus sign is parsed,
>the unary behavour is unnoticed in this case 
>by the parsing engine [back to js, please]:
>
>let  r1 = -2 ^ 2; // -2
>
>... even if it is just unforgivable as in:
>
>let  r2 = 0 + -2 ^ 2; // -2

The problem is that 
  -3**2
could be parsed as 
  (-3)**2 == 9
or as
  -(3**2) == -9

Which would you prefer? How would you justify your choice to people
complaining loudly that the other way is the *obvious* way!

I'm guessing the ECMA262 committee decided to avoid arguments.

  John

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#33212

John G Harris <niam@jghnorth.org.uk.invalid> wrote on 05 May 2017 in 
comp.lang.javascript:

> On Fri, 05 May 2017 09:16:13 +0200, "Evertjan."
> <exxjxw.hannivoort@inter.nl.net> wrote:
> 
>   <snip>
>>Even so, it seems that the way the minus sign is parsed,
>>the unary behavour is unnoticed in this case 
>>by the parsing engine [back to js, please]:
>>
>>let  r1 = -2 ^ 2; // -2
>>
>>... even if it is just unforgivable as in:
>>
>>let  r2 = 0 + -2 ^ 2; // -2
> 
> The problem is that 
>   -3**2
> could be parsed as 
>   (-3)**2 == 9
> or as
>   -(3**2) == -9
> 
> Which would you prefer? How would you justify your choice to people
> complaining loudly that the other way is the *obvious* way!

I said what I find unforgivable parsing above,
as it is clearly an unary minus,
I repeat it here:

let  r2 = 0 + -2 ^ 2; // -2;

I'm not in the least interested in justifying choices on demand.

> I'm guessing the ECMA262 committee decided to avoid arguments.

If that were the case they obviously failed.

Methinks your guess is wrong, as the ECMA262 committee should go for 
symplicity, logic and consistency, not for avoiding arguments.

After all, what is wrong with arguments, unless you are indoctrinated from 
childhood that that is against some deity's will?

-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#33231

On Fri, 05 May 2017 11:16:13 +0200, "Evertjan."
<exxjxw.hannivoort@inter.nl.net> wrote:

  <snip>
>I said what I find unforgivable parsing above,
>as it is clearly an unary minus,
>I repeat it here:
>
>let  r2 = 0 + -2 ^ 2; // -2;

Equally clearly a negative number is being raised to the power 2, so
the result is +4, not -4.


>I'm not in the least interested in justifying choices on demand.
  <snip>

But you are willing to say your choice is the only right one.

  John

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#33233

John G Harris <niam@jghnorth.org.uk.invalid> wrote on 06 May 2017 in 
comp.lang.javascript:

> On Fri, 05 May 2017 11:16:13 +0200, "Evertjan."
> <exxjxw.hannivoort@inter.nl.net> wrote:
> 
>   <snip>
>>I said what I find unforgivable parsing above,
>>as it is clearly an unary minus,
>>I repeat it here:
>>
>>let  r2 = 0 + -2 ^ 2; // -2;
> 
> Equally clearly a negative number is being raised to the power 2, so
> the result is +4, not -4.

Sorry, meant -4 and 4.

>>I'm not in the least interested in justifying choices on demand.
>   <snip>
> 
> But you are willing to say your choice is the only right one.

NOT AT ALL.

[I don't under stand the "willing to" part, I either say something or I 
don't in a NG. Or did you forget a question-mark?]

I do not claim that I am right, I try to learn from discussion,
and, starting off with my argumented ideas, I am open to argumented 
arguments to the contrary.

"the only right one"?

I do not think there is a single right way of defining operator precedence 
in JS-parsing, but we still can argue about [personal or group] preference.

-- 
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

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#33197

At Thu, 4 May 2017 14:13:23 -0000 (UTC) Jon Ribbens <jon+usenet@unequivocal.eu> wrote:

> 
> On 2017-05-04, Stefan Ram <ram@zedat.fu-berlin.de> wrote:
> >   In a recent Firefox:
> >
> > -2 ** 2
> >
> > SyntaxError: unparenthesized unary expression can't appear on
> > the left-hand side of '**'
> >
> >   . Can't seem to find the corresponding rule in a recent copy
> >   of ECMAScript (12.6), though.
> 
> Chrome behaves similarly:
> 
>   -2 ** 2
>   Uncaught SyntaxError: Unexpected token **
>   (-2) ** 2
>   4
> 
> Presumably this is a sensible thing to avoid bugs, e.g. Python does
> this:
> 
>   >>> -2**2
>   -4
>   >>> (-2)**2
>   4
> 
> I think most people would expect both expressions to equal 4.

There is uncertainity as what the presidence of unary - vs binary **/^ should
be -- different languages do different things. One way out is to require
parens.

>    

-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller@deepsoft.com       -- Webhosting Services
                                                                                                      

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#33198

On 05/04/2017 09:13 AM, Jon Ribbens wrote:

[snip]

>   >>> -2**2
>   -4
>   >>> (-2)**2
>   4
>
> I think most people would expect both expressions to equal 4.
>

Unless parentheses are used, exponentiation is supposed to be performed 
before subtraction. -4 is correct for the first expression.

BTW, you might want to try to find the square root or -4. Both of them 
(EVERY number has 2 square roots).

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#33200

On Thu, 4 May 2017 12:04:12 -0500, Sam E
<why.should.this@be.email.invalid> wrote:

  <snip>
>(EVERY number has 2 square roots).

0 doesn't :-)

  John

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#33201

In article <vksmgcp498jf6afkpqavb926g2rhaoj6uh@4ax.com>, John G Harris
<niam@jghnorth.org.uk.invalid> wrote:

>On Thu, 4 May 2017 12:04:12 -0500, Sam E
><why.should.this@be.email.invalid> wrote:
>
>  <snip>
>>(EVERY number has 2 square roots).
>
>0 doesn't :-)

What about on 1s-complement computers?

-- 
"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689

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#33210

On Thu, 04 May 2017 19:51:33 +0100, Tim Streater
<timstreater@greenbee.net> wrote:

>In article <vksmgcp498jf6afkpqavb926g2rhaoj6uh@4ax.com>, John G Harris
><niam@jghnorth.org.uk.invalid> wrote:
>
>>On Thu, 4 May 2017 12:04:12 -0500, Sam E
>><why.should.this@be.email.invalid> wrote:
>>
>>  <snip>
>>>(EVERY number has 2 square roots).
>>
>>0 doesn't :-)
>
>What about on 1s-complement computers?

I was talking maths. Computers can be approximate, or plain wrong.

  John

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#33216

Tim Streater <timstreater@greenbee.net> wrote:

>"That excessive bail ought not to be required, nor excessive fines imposed,
>nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689

1689? The Bill of Rights became part of the constitution on December
15, 1791.

-- 
Tim Slattery
tim <at> risingdove <dot> com

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#33217

Tim Slattery wrote:

> Tim Streater <timstreater@greenbee.net> wrote:
>> "That excessive bail ought not to be required, nor excessive fines
>> imposed, nor cruel and unusual punishments inflicted"  --  Bill of Rights 
>> 1689
> 
> 1689? The Bill of Rights became part of the constitution on December
> 15, 1791.

There is not only the United States of America.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | <http://PointedEars.de/es-matrix>
<https://github.com/PointedEars> | <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | Please do not cc me./Bitte keine Kopien per E-Mail.

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#33218

In article <vq4pgch7qi0t27p9io6u7569mkv0u5fh6l@4ax.com>, Tim Slattery
<tim@risingdove.com> wrote:

>Tim Streater <timstreater@greenbee.net> wrote:
>
>>"That excessive bail ought not to be required, nor excessive fines imposed,
>>nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689
>
>1689? The Bill of Rights became part of the constitution on December
>15, 1791.

Look up the 1689 Bill of Rights in Winky, you fathead.

-- 
"People don't buy Microsoft for quality, they buy it for compatibility
with what Bob in accounting bought last year. Trace it back - they buy
Microsoft because the IBM Selectric didn't suck much" - P Seebach, afc

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#33237

Tim Streater <timstreater@greenbee.net> wrote:

>In article <vq4pgch7qi0t27p9io6u7569mkv0u5fh6l@4ax.com>, Tim Slattery
><tim@risingdove.com> wrote:
>
>>Tim Streater <timstreater@greenbee.net> wrote:
>>
>>>"That excessive bail ought not to be required, nor excessive fines imposed,
>>>nor cruel and unusual punishments inflicted"  --  Bill of Rights 1689
>>
>>1689? The Bill of Rights became part of the constitution on December
>>15, 1791.
>
>Look up the 1689 Bill of Rights in Winky, you fathead.

A British bill of Rights? OK, I didn't know that. The language you
quoted is almost identical to the 8th amendment to the US
Constitution:

Excessive bail shall not be required, nor excessive fines imposed, nor
cruel and unusual punishments inflicted.

No doubt whoever drafted our 8th (George Mason, I thin?) cribbed from
the older document.

-- 
Tim Slattery
tim <at> risingdove <dot> com

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#33238

Tim Slattery wrote:

> Tim Streater <timstreater@greenbee.net> wrote:
>> In article <vq4pgch7qi0t27p9io6u7569mkv0u5fh6l@4ax.com>, Tim Slattery
>> <tim@risingdove.com> wrote:
>>> Tim Streater <timstreater@greenbee.net> wrote:
>>>> "That excessive bail ought not to be required, nor excessive fines
>>>> imposed, nor cruel and unusual punishments inflicted"  --  Bill of
>>>> Rights 1689
>>> 1689? The Bill of Rights became part of the constitution on December
>>> 15, 1791.
>> Look up the 1689 Bill of Rights in Winky, you fathead.
> 
> A British bill of Rights? OK, I didn't know that. The language you
> quoted is almost identical to the 8th amendment to the US
> Constitution:
> […]

That might have to do with the fact that the United States of America 
*originated from British colonies*…

<https://en.wikipedia.org/wiki/United_States#Settlements> pp.

(Good grief.  I am not a citizen of the USA and know more about its history 
than you.  No surprise that DeVos managed to become Secretary of Education…)

> No doubt whoever drafted our 8th (George Mason, I thin?)

_James Madison_ (later 4th POTUS)

> cribbed from the older document.

<https://en.wikipedia.org/wiki/United_States_Bill_of_Rights#Crafting_amendments> 
pp.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | <http://PointedEars.de/es-matrix>
<https://github.com/PointedEars> | <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | Please do not cc me./Bitte keine Kopien per E-Mail.

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