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Groups > comp.lang.javascript > #26110 > unrolled thread
| Started by | Swifty <steve.j.swift@gmail.com> |
|---|---|
| First post | 2014-11-11 12:38 +0000 |
| Last post | 2014-11-14 04:34 +0100 |
| Articles | 20 on this page of 97 — 16 participants |
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Date arithmetic Swifty <steve.j.swift@gmail.com> - 2014-11-11 12:38 +0000
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-11 15:10 +0100
Re: Date arithmetic Swifty <steve.j.swift@gmail.com> - 2014-11-11 22:07 +0000
Re: Date arithmetic Tim Streater <timstreater@greenbee.net> - 2014-11-11 22:37 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-12 02:40 +0100
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-12 08:21 +0100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-13 15:27 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-13 21:26 +0100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-14 14:16 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-15 07:13 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-15 19:36 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-16 17:24 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-16 18:49 +0100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-17 00:14 +0100
Re: Date arithmetic Dr J R Stockton <J.R.Stockton@physics.org> - 2014-11-16 10:51 -0800
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-16 20:17 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-17 00:52 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-17 01:11 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-18 16:18 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-19 11:00 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-21 22:58 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-22 18:33 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-23 19:38 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-24 01:14 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-25 21:17 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-26 18:25 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-27 19:34 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-28 01:25 +0100
Re: Date arithmetic Dr J R Stockton <J.R.Stockton@physics.org> - 2014-11-28 05:29 -0800
Re: Date arithmetic Andrew Poulos <ap_prog@hotmail.com> - 2014-11-28 11:44 +1100
Re: Date arithmetic Dr J R Stockton <J.R.Stockton@physics.org> - 2014-11-28 04:52 -0800
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-28 14:24 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-28 14:47 +0100
Re: Date arithmetic Dr J R Stockton <J.R.Stockton@physics.org> - 2014-11-28 06:12 -0800
Re: Date arithmetic Andrew Poulos <ap_prog@hotmail.com> - 2014-11-29 16:59 +1100
Re: Date arithmetic John Harris <niam@jghnorth.org.uk.invalid> - 2014-11-29 20:05 +0000
Re: Date arithmetic Joao Rodrigues <groups_jr-1@yahoo.com> - 2014-11-29 23:47 -0200
Re: Date arithmetic Andrew Poulos <ap_prog@hotmail.com> - 2014-12-01 10:44 +1100
Re: Date arithmetic Tim Streater <timstreater@greenbee.net> - 2014-11-30 23:54 +0000
Re: Date arithmetic Andrew Poulos <ap_prog@hotmail.com> - 2014-12-01 13:01 +1100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-17 01:34 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-17 01:41 +0100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-18 19:06 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-18 16:26 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-19 17:52 +0100
Re: Date arithmetic Gene Wirchenko <genew@telus.net> - 2014-11-19 09:44 -0800
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-19 19:34 +0100
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-19 19:13 +0000
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-19 22:18 +0100
Re: Date arithmetic Gene Wirchenko <genew@telus.net> - 2014-11-19 13:43 -0800
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-19 22:40 +0000
Re: Date arithmetic Tim Streater <timstreater@greenbee.net> - 2014-11-19 22:51 +0000
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-19 23:35 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-19 23:10 +0100
Re: Date arithmetic Tim Streater <timstreater@greenbee.net> - 2014-11-19 22:32 +0000
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-19 23:26 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-20 00:47 +0100
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-20 00:17 +0000
Re: Date arithmetic Dr J R Stockton <J.R.Stockton@physics.org> - 2014-11-20 01:18 -0800
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-20 13:47 +0000
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-21 22:29 +0000
Re: Date arithmetic Joao Rodrigues <groups_jr-1@yahoo.com.br> - 2014-11-19 19:24 -0200
Re: Date arithmetic Gene Wirchenko <genew@telus.net> - 2014-11-19 13:40 -0800
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-19 23:40 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-18 16:44 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-19 11:20 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-14 20:45 +0000
Re: Date arithmetic "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2014-11-15 14:13 -0800
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-15 23:42 +0100
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-11-12 00:23 +0100
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-12 13:24 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-12 14:43 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-12 19:48 +0100
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-13 01:18 +0100
Re: Date arithmetic Ben Bacarisse <ben.usenet@bsb.me.uk> - 2014-11-12 20:19 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-13 03:42 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-12 20:06 +0000
Re: Date arithmetic RobG <rgqld@iinet.net.au> - 2014-11-23 20:51 -0800
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-25 20:08 +0000
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-26 01:31 +0100
Re: Date arithmetic RobG <rgqld@iinet.net.au> - 2014-12-08 19:42 -0800
Re: Date arithmetic "Christoph M. Becker" <cmbecker69@arcor.de> - 2014-11-26 01:40 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-26 22:07 +0100
Re: Date arithmetic RobG <rgqld@iinet.net.au> - 2014-12-08 21:41 -0800
Re: Date arithmetic "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2014-12-09 09:47 +0100
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-12-09 14:17 +0100
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-12-10 23:34 +0000
Re: Date arithmetic RobG <rgqld@iinet.net.au> - 2014-12-10 17:21 -0800
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-12-13 17:19 +0000
Re: Date arithmetic RobG <rgqld@iinet.net.au> - 2014-12-10 18:35 -0800
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-11 22:29 +0100
Re: Date arithmetic Swifty <steve.j.swift@gmail.com> - 2014-11-11 21:53 +0000
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-11 23:43 +0100
Re: Date arithmetic John Harris <niam@jghnorth.org.uk.invalid> - 2014-11-12 15:49 +0000
Re: Date arithmetic Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> - 2014-11-12 19:58 +0000
Re: Date arithmetic Dr.Kral@nyc.rr.com - 2014-11-13 20:24 -0500
Re: Date arithmetic Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2014-11-14 04:34 +0100
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| From | "Christoph M. Becker" <cmbecker69@arcor.de> |
|---|---|
| Date | 2014-11-17 01:34 +0100 |
| Message-ID | <m4bfqm$7lo$1@solani.org> |
| In reply to | #26150 |
Thomas 'PointedEars' Lahn wrote: > Dr J R Stockton wrote: > >> You mean days between February and January in that order. > > No, he means what he wrote, and, with the exception of the use of “between” > (which should be “from”, and month names are always capitalized), I concur. It seems to me that "between ... and" is open to interpretation. I meant the closed interval [March, December] (as used in SQL's between ... and), John the open interval ]February, January[ (January of the following year). Obviously, both are the same. If I had written "from March to December", the confusion probably would have been avoided (thanks for the pointer). >> Unsubtle. The first part of the expression seems derived from, but does >> not take full benefit from, Zeller's Congruence > > Interesting. If it has not already happened and proves to be correct, this > information should be added as reference to the Wikipedia article I took the > approach from. ACK. >> But we know that Swifty wants to process his _hand-entered_ dates. >> A quick test in current Firefox on an elderly PC shows that it executes a >> million of 'new Date()' in about 2.2 seconds. So there can be no >> perceptible advantage in doing anything other than 'new Date()' on each >> input, subtracting, dividing by 864e5, and rounding to integer, to get >> Swifty his date difference. > > You are missing the point and are preaching to the choir. It has already > been stated twice (at least) in this thread that for this use-case the > approach in jsx.date.getDayOfYear() is not the most efficient one, and that > the division approach is probably the best one. After all, it was Christoph > who suggested it first, in this thread at least. That is not correct. It has been Evertjan to first suggest the division in this thread[1] (if I'm not mistaken). My suggestion was meant to avoid any potential DST related issues, and to stick with proper integer calculations (what might be somewhat dangerous considering that ECMAScript Numbers are floating point values). [1] <news:XnsA3E354F8EA950eejj99@194.109.133.133> -- Christoph M. Becker
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| From | Thomas 'PointedEars' Lahn <PointedEars@web.de> |
|---|---|
| Date | 2014-11-17 01:41 +0100 |
| Message-ID | <4619702.bvc2cBK1RH@PointedEars.de> |
| In reply to | #26152 |
Christoph M. Becker wrote: > Thomas 'PointedEars' Lahn wrote: >> Dr J R Stockton wrote: >>> It has already been stated twice (at least) in this thread that for this >>> use-case the approach in jsx.date.getDayOfYear() is not the most >>> efficient one, and that the division approach is probably the best one. >>> After all, it was Christoph who suggested it first, in this thread at >>> least. > > That is not correct. It has been Evertjan to first suggest the division > in this thread[1] (if I'm not mistaken). According to my newsreader, you are correct. But it was not his suggestion I was referring to with “division approach”: > My suggestion was meant to avoid any potential DST related issues, and to > stick with proper integer calculations (what might be somewhat dangerous > considering that ECMAScript Numbers are floating point values). > > [1] <news:XnsA3E354F8EA950eejj99@194.109.133.133> See my clarification in <news:40469088.RWZSUOfdCW@PointedEars.de>, which will probably have been distributed to you at the time you read this message. -- PointedEars FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/> Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix> Please do not Cc: me. / Bitte keine Kopien per E-Mail.
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| From | "Christoph M. Becker" <cmbecker69@arcor.de> |
|---|---|
| Date | 2014-11-18 19:06 +0100 |
| Message-ID | <m4g1rd$l3a$3@solani.org> |
| In reply to | #26153 |
Thomas 'PointedEars' Lahn wrote: > See my clarification in <news:40469088.RWZSUOfdCW@PointedEars.de>, which > will probably have been distributed to you at the time you read this > message. Ah, I see. Thanks for the clarification. :) -- Christoph M. Becker
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| From | Dr J R Stockton <reply1400@merlyn.demon.co.uk.invalid> |
|---|---|
| Date | 2014-11-18 16:26 +0000 |
| Message-ID | <sTmTP8e4M3aUFwP1@invalid.uk.co.demon.merlyn.invalid> |
| In reply to | #26152 |
In comp.lang.javascript message <m4bfqm$7lo$1@solani.org>, Mon, 17 Nov 2014 01:34:25, Christoph M. Becker <cmbecker69@arcor.de> posted: >My suggestion was meant to ) ..., >and to stick with proper integer >calculations (what might be somewhat dangerous considering that >ECMAScript Numbers are floating point values). The Date range has been chosen such that every millisecond within the range is represented exactly in an ECMAScript float. One only needs to be careful not to multiply and get a result outside the allotted 10^8 days. -- (c) John Stockton, nr London UK Reply address via Merlyn Home Page. news:comp.lang.javascript FAQ <http://www.jibbering.com/faq/index.html>. <http://www.merlyn.demon.co.uk/js-index.htm> jscr maths, dates, sources. <http://www.merlyn.demon.co.uk/> TP/BP/Delphi/jscr/&c, FAQ items, links.
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| From | "Christoph M. Becker" <cmbecker69@arcor.de> |
|---|---|
| Date | 2014-11-19 17:52 +0100 |
| Message-ID | <m4ihsi$nm9$1@solani.org> |
| In reply to | #26156 |
Dr J R Stockton wrote: > In comp.lang.javascript message <m4bfqm$7lo$1@solani.org>, Mon, 17 Nov > 2014 01:34:25, Christoph M. Becker <cmbecker69@arcor.de> posted: > >> My suggestion was meant to > ) ..., >> and to stick with proper integer >> calculations (what might be somewhat dangerous considering that >> ECMAScript Numbers are floating point values). > > > The Date range has been chosen such that every millisecond within the > range is represented exactly in an ECMAScript float. One only needs to > be careful not to multiply and get a result outside the allotted 10^8 > days. ACK -- assuming that there are no implementation errors. I rarely do float calculations in ECMAScript implementations, so I don't know if this assumption is reasonable. Probably it is. -- Christoph M. Becker
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| From | Gene Wirchenko <genew@telus.net> |
|---|---|
| Date | 2014-11-19 09:44 -0800 |
| Message-ID | <knlp6a9uast6icgb6mkf8l964d3gjbdbge@4ax.com> |
| In reply to | #26162 |
On Wed, 19 Nov 2014 17:52:40 +0100, "Christoph M. Becker"
<cmbecker69@arcor.de> wrote:
[snip]
>ACK -- assuming that there are no implementation errors. I rarely do
>float calculations in ECMAScript implementations, so I don't know if
>this assumption is reasonable. Probably it is.
Since it is the only number type available for variables, how do
you avoid it?
Sincerely,
Gene Wirchenko
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| From | "Evertjan." <exxjxw.hannivoort@inter.nl.net> |
|---|---|
| Date | 2014-11-19 19:34 +0100 |
| Message-ID | <XnsA3EAC729338EBeejj99@194.109.133.133> |
| In reply to | #26163 |
Gene Wirchenko <genew@telus.net> wrote on 19 nov 2014 in comp.lang.javascript: > On Wed, 19 Nov 2014 17:52:40 +0100, "Christoph M. Becker" > <cmbecker69@arcor.de> wrote: > > [snip] > >>ACK -- assuming that there are no implementation errors. I rarely do >>float calculations in ECMAScript implementations, so I don't know if >>this assumption is reasonable. Probably it is. > > Since it is the only number type available for variables, What about integers? > how do you avoid it? > > Sincerely, > > Gene Wirchenko > -- Evertjan. The Netherlands. (Please change the x'es to dots in my emailaddress)
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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-19 19:13 +0000 |
| Message-ID | <877fyr3sxr.fsf@bsb.me.uk> |
| In reply to | #26164 |
"Evertjan." <exxjxw.hannivoort@inter.nl.net> writes: > Gene Wirchenko <genew@telus.net> wrote on 19 nov 2014 in > comp.lang.javascript: > >> On Wed, 19 Nov 2014 17:52:40 +0100, "Christoph M. Becker" >> <cmbecker69@arcor.de> wrote: >> >> [snip] >> >>>ACK -- assuming that there are no implementation errors. I rarely do >>>float calculations in ECMAScript implementations, so I don't know if >>>this assumption is reasonable. Probably it is. >> >> Since it is the only number type available for variables, > > What about integers? ECMAScript does not have a separate integer type. You can represent any integer in (2^53, 2^53) exactly (and zero twice!) using the built-in Number type, but you are still using a floating point type as far as the language definition goes. <snip> -- Ben.
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| From | "Evertjan." <exxjxw.hannivoort@inter.nl.net> |
|---|---|
| Date | 2014-11-19 22:18 +0100 |
| Message-ID | <XnsA3EAE2E07B3D9eejj99@194.109.133.133> |
| In reply to | #26165 |
Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 19 nov 2014 in comp.lang.javascript: >>> Since it is the only number type available for variables, >> >> What about integers? > > ECMAScript does not have a separate integer type. You can represent any > integer in (2^53, 2^53) exactly (and zero twice!) using the built-in > Number type, but you are still using a floating point type as far as the > language definition goes. So what? I can define integer and put that into a javascript variable, you only define "integer type" differently from mine. I can define date/time and put that into a javascript variable, I even have internal javascript functions supporting that data type, why should I be concerned about the internal representation? I can define boolean true/false and put that into a javascript variable, you only define "boolean type" differently from mine. I can define a string as an decimal or hexadecimal or binary integer type, certainly that is a "number type", and store that into a variable. -- Evertjan. The Netherlands. (Please change the x'es to dots in my emailaddress)
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| From | Gene Wirchenko <genew@telus.net> |
|---|---|
| Date | 2014-11-19 13:43 -0800 |
| Message-ID | <6i3q6ap99050vgd1u3ecve4a8187sdqi5u@4ax.com> |
| In reply to | #26166 |
On Wed, 19 Nov 2014 22:18:10 +0100, "Evertjan."
<exxjxw.hannivoort@inter.nl.net> wrote:
>Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 19 nov 2014 in
>comp.lang.javascript:
>
>>>> Since it is the only number type available for variables,
>>>
>>> What about integers?
>>
>> ECMAScript does not have a separate integer type. You can represent any
>> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in
>> Number type, but you are still using a floating point type as far as the
>> language definition goes.
>
>So what?
>
>I can define integer and put that into a javascript variable,
>you only define "integer type" differently from mine.
The variable, if it holds a numeric value, is holding a
floating-point value. Yes, some integers can fit in that, but the
variable type of Number is a floating-point type.
>I can define date/time and put that into a javascript variable,
>I even have internal javascript functions supporting that data type,
>why should I be concerned about the internal representation?
Maybe, for your values, you do not need to. Nonetheless, the
type exists.
>I can define boolean true/false and put that into a javascript variable,
>you only define "boolean type" differently from mine.
>
>I can define a string as an decimal or hexadecimal or binary integer type,
>certainly that is a "number type",
>and store that into a variable.
Yup, and all of those values are being stored as floating-point.
Sincerely,
Gene Wirchenko
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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-19 22:40 +0000 |
| Message-ID | <87ppci3jct.fsf@bsb.me.uk> |
| In reply to | #26166 |
"Evertjan." <exxjxw.hannivoort@inter.nl.net> writes: > Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 19 nov 2014 in > comp.lang.javascript: > >>>> Since it is the only number type available for variables, >>> >>> What about integers? >> >> ECMAScript does not have a separate integer type. You can represent any >> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in >> Number type, but you are still using a floating point type as far as the >> language definition goes. > > So what? Some people don't know that ECMAScript has only one Number type, and your remark might have misled other into thinking otherwise, so I think more explanation is helpful. That's all. > I can define integer and put that into a javascript variable, > you only define "integer type" differently from mine. Sure, but personal definitions of terms that have a technical meaning in a particular language are often more confusing than helpful. If you like to think of Number variables that contain the floating point representation of a whole number as having "integer type" that's fine, but it's almost certainly going to be pointed out that you are not using the standard meaning. <snip> -- Ben.
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| From | Tim Streater <timstreater@greenbee.net> |
|---|---|
| Date | 2014-11-19 22:51 +0000 |
| Message-ID | <191120142251329551%timstreater@greenbee.net> |
| In reply to | #26172 |
In article <87ppci3jct.fsf@bsb.me.uk>, Ben Bacarisse <ben.usenet@bsb.me.uk> wrote: > "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes: > > > Ben Bacarisse <ben.usenet@bsb.me.uk> wrote on 19 nov 2014 in > > comp.lang.javascript: > > > >>>> Since it is the only number type available for variables, > >>> > >>> What about integers? > >> > >> ECMAScript does not have a separate integer type. You can represent any > >> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in > >> Number type, but you are still using a floating point type as far as the > >> language definition goes. > > > > So what? > > Some people don't know that ECMAScript has only one Number type, and > your remark might have misled other into thinking otherwise, so I think > more explanation is helpful. That's all. There's nothing new about using floating point for integers anyway. The CDC 6600 only had floating point hardware. -- "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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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-19 23:35 +0000 |
| Message-ID | <87egsy3gs3.fsf@bsb.me.uk> |
| In reply to | #26174 |
Tim Streater <timstreater@greenbee.net> writes: > In article <87ppci3jct.fsf@bsb.me.uk>, Ben Bacarisse > <ben.usenet@bsb.me.uk> wrote: <snip> >> Some people don't know that ECMAScript has only one Number type, and >> your remark might have misled other into thinking otherwise, so I think >> more explanation is helpful. That's all. > > There's nothing new about using floating point for integers anyway. The > CDC 6600 only had floating point hardware. Indeed. But I think it's helpful to distinguish between a language and its implementation. For example, the CDC 6600 supported FORTRAN 66 with its distinction between integer and real types. The integer types where implemented using floating point but they behaved as specified by the language specification. Likewise, an ECMAScript implementation is permitted to use integer hardware in various ways, provided the results conform with all the details of the language specification. -- Ben.
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| From | Thomas 'PointedEars' Lahn <PointedEars@web.de> |
|---|---|
| Date | 2014-11-19 23:10 +0100 |
| Message-ID | <1460968.O2UKaiCUXN@PointedEars.de> |
| In reply to | #26165 |
Ben Bacarisse wrote:
> ECMAScript does not have a separate integer type. You can represent any
> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in
^^^^^^^^^^^^^^^?
> Number type, but you are still using a floating point type as far as the
> language definition goes.
So far as Editions up to 5.1 are concerned, and if we are excluding the
implemented ES4 draft.
--
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.
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| From | Tim Streater <timstreater@greenbee.net> |
|---|---|
| Date | 2014-11-19 22:32 +0000 |
| Message-ID | <191120142232431812%timstreater@greenbee.net> |
| In reply to | #26165 |
In article <877fyr3sxr.fsf@bsb.me.uk>, Ben Bacarisse <ben.usenet@bsb.me.uk> wrote: > "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes: > > > Gene Wirchenko <genew@telus.net> wrote on 19 nov 2014 in > > comp.lang.javascript: > > > >> On Wed, 19 Nov 2014 17:52:40 +0100, "Christoph M. Becker" > >> <cmbecker69@arcor.de> wrote: > >> > >> [snip] > >> > >>>ACK -- assuming that there are no implementation errors. I rarely do > >>>float calculations in ECMAScript implementations, so I don't know if > >>>this assumption is reasonable. Probably it is. > >> > >> Since it is the only number type available for variables, > > > > What about integers? > > ECMAScript does not have a separate integer type. You can represent any > integer in (2^53, 2^53) exactly (and zero twice!) using the built-in > Number type, but you are still using a floating point type as far as the > language definition goes. Why twice? is the javascript VM a ones-complement machine? -- "A committee is a cul-de-sac down which ideas are lured and then quietly strangled." - Sir Barnett Cocks (1907-1989)
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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-19 23:26 +0000 |
| Message-ID | <87k32q3h7i.fsf@bsb.me.uk> |
| In reply to | #26171 |
Tim Streater <timstreater@greenbee.net> writes: > In article <877fyr3sxr.fsf@bsb.me.uk>, Ben Bacarisse > <ben.usenet@bsb.me.uk> wrote: > >> "Evertjan." <exxjxw.hannivoort@inter.nl.net> writes: >> >> > Gene Wirchenko <genew@telus.net> wrote on 19 nov 2014 in > >> comp.lang.javascript: >> > >> >> On Wed, 19 Nov 2014 17:52:40 +0100, "Christoph M. Becker" >> >> <cmbecker69@arcor.de> wrote: >> >> >> [snip] >> >> >>>ACK -- assuming that there are no implementation errors. I >> rarely do >> >>>float calculations in ECMAScript implementations, so I don't know if >> >>>this assumption is reasonable. Probably it is. >> >> >> Since it is the only number type available for variables, >> > >> > What about integers? >> >> ECMAScript does not have a separate integer type. You can represent any >> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in >> Number type, but you are still using a floating point type as far as the >> language definition goes. > > Why twice? is the javascript VM a ones-complement machine? I'm talking about what the recent (5.1) language standard says. The Number type uses the IEEE 754 64-bit floating point format in which (to quote) "there is both a positive zero and a negative zero" but you have to work hard to find out which one you have! -- Ben.
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| From | "Christoph M. Becker" <cmbecker69@arcor.de> |
|---|---|
| Date | 2014-11-20 00:47 +0100 |
| Message-ID | <m4ja5p$hdd$1@solani.org> |
| In reply to | #26175 |
Ben Bacarisse wrote: > Tim Streater <timstreater@greenbee.net> writes: > >> In article <877fyr3sxr.fsf@bsb.me.uk>, Ben Bacarisse >> <ben.usenet@bsb.me.uk> wrote: >> >>> ECMAScript does not have a separate integer type. You can represent any >>> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in >>> Number type, but you are still using a floating point type as far as the >>> language definition goes. >> >> Why twice? is the javascript VM a ones-complement machine? > > I'm talking about what the recent (5.1) language standard says. The > Number type uses the IEEE 754 64-bit floating point format in which (to > quote) "there is both a positive zero and a negative zero" but you have > to work hard to find out which one you have! To be precise, the IEEE 754 double-precision 64-bit *binary* format. :) -- Christoph M. Becker
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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-20 00:17 +0000 |
| Message-ID | <878uj63ett.fsf@bsb.me.uk> |
| In reply to | #26177 |
"Christoph M. Becker" <cmbecker69@arcor.de> writes: > Ben Bacarisse wrote: > >> Tim Streater <timstreater@greenbee.net> writes: >> >>> In article <877fyr3sxr.fsf@bsb.me.uk>, Ben Bacarisse >>> <ben.usenet@bsb.me.uk> wrote: >>> >>>> ECMAScript does not have a separate integer type. You can represent any >>>> integer in (2^53, 2^53) exactly (and zero twice!) using the built-in >>>> Number type, but you are still using a floating point type as far as the >>>> language definition goes. >>> >>> Why twice? is the javascript VM a ones-complement machine? >> >> I'm talking about what the recent (5.1) language standard says. The >> Number type uses the IEEE 754 64-bit floating point format in which (to >> quote) "there is both a positive zero and a negative zero" but you have >> to work hard to find out which one you have! > > To be precise, the IEEE 754 double-precision 64-bit *binary* > format. :) Very true. -- Ben.
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| From | Dr J R Stockton <J.R.Stockton@physics.org> |
|---|---|
| Date | 2014-11-20 01:18 -0800 |
| Message-ID | <e73cadd0-6090-44f3-b4d3-62b7d811918b@googlegroups.com> |
| In reply to | #26175 |
On Wednesday, November 19, 2014 11:26:33 PM UTC, Ben Bacarisse wrote: > I'm talking about what the recent (5.1) language standard says. The > Number type uses the IEEE 754 64-bit floating point format in which (to > quote) "there is both a positive zero and a negative zero" but you have > to work hard to find out which one you have! If the number X is known to be finite, it is only necessary to compare its reciprocal with [either] zero. Otherwise, compare (X+1/X) with a zero. It's not hard, if one is smart. That has been discussed here in the past few years, and should be put in the newsgroup FAQ. -- (c) John Stockton, near London, UK. Using Google, no spell-check. Mail: J.R.""""""""@physics.org or (better) via Home Page at Web: <http://www.merlyn.demon.co.uk/> (may move soon) FAQish topics, acronyms, links, etc.; Date, Lagrange, JavaScript, ..|
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| From | Ben Bacarisse <ben.usenet@bsb.me.uk> |
|---|---|
| Date | 2014-11-20 13:47 +0000 |
| Message-ID | <87zjbmx9uc.fsf@bsb.me.uk> |
| In reply to | #26179 |
Dr J R Stockton <J.R.Stockton@physics.org> writes: <snip> > It's not hard, if one is smart. Yes, "you have to work hard" was not a good phrase to use in a technical group! I meant that expressions that reveal the sign of the zero are quite rare. <snip> -- Ben.
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