Template talk:Convert/Archive December 2017

bytes per inch of tape
At IBM 3480 Family (and probably other articles about magnetic storage tapes) there are instances of constructions like "38,000 bytes per inch of tape" that I'd like to add a conversion for into bytes per cm of tape, but I can't figure out how to do that. I guess it might be possible using the extra words or automatic per units functions, but the examples for both are based around (convertible units)/(fixed words) rather than (fixed words)/(convertible units) that would be needed here. Thryduulf (talk) 13:40, 20 November 2017 (UTC)
 * Found this. Almost:
 * 1000 /inch &rarr; 1000 /inch
 * -DePiep (talk) 13:59, 20 November 2017 (UTC)
 * That's not perfect but I'll use it. Thanks, Thryduulf (talk) 19:26, 20 November 2017 (UTC)
 * also accepts two unnamed parameters, the first goes before the input unit, and the second goes before the output unit.
 * → 1000 /inch
 * Johnuniq (talk) 21:38, 20 November 2017 (UTC)
 * Thank you, that's even better although "38,000 bytes per inch of tape (15,000 bytes/cm)" would be perfection. Thryduulf (talk) 21:47, 20 November 2017 (UTC)
 * Thryduulf, there is also 1000 /inch and 1000 /inch. Frietjes (talk) 20:34, 8 December 2017 (UTC)

Light speed
Would it be possible to add c to the list of speed units? Sheila1988 (talk) 00:12, 9 December 2017 (UTC)


 * It is not clear that this would make sense, even though it is often enough used like an informal unit. In particular, it is not regarded as a unit, but rather as a physical constant, just like the e, the ħ and others.  —Quondum 00:24, 9 December 2017 (UTC)


 * e and ħ are dimensionless constants but c is definitely a velocity. The only real question is whether it is taken as the speed of light in a vacuum or in the surrounding medium (the speed of light in air is less and the speed of light in water is even less again).  Stepho  talk 11:25, 9 December 2017 (UTC)


 * I was thinking it could be used for the speeds of spacecraft and satellites, and orbital velocities Sheila1988 (talk) 12:39, 9 December 2017 (UTC)
 * This being, we need actual usage examples like: "It travels at 0.9 c (270,000 km/s, 167,000 mi/s)". -DePiep (talk) 12:46, 9 December 2017 (UTC)

Module version 20
Some changes to the convert modules are in the sandbox, and I intend switching the main modules to use the sandbox soon.

The examples use fixed wikitext for the output to show what the new version would produce so they will not change in the future.


 * Removed temporary  parameter added in April 2017 when testing Wikidata qualifiers as it not needed. Discussion here and here.
 * Automatic per units insert parentheses around the bottom unit if it has a dot. This is from Quondum's report here. I originally said this would be too complex but a reasonable solution which works at least for simple cases was found. Some examples are unsatisfactory but they are unlikely to occur:
 * → 12.3 g/(kW⋅h) or 0.020 lb/(hp⋅h)
 * → 12.3 J/(N⋅m) (4.0 cal/(lbf⋅ft))
 * → 12.3 J/(lb/(lbf⋅h)) (0.104 cal/(g/(kN⋅s)))

Release notes for earlier versions are listed here. Johnuniq (talk) 09:52, 8 December 2017 (UTC)
 * Omit the specified output unit if the input is a Wikidata property which uses the same unit as the output. The result will use the default output unit instead of converting to the same unit. This arose at South Pole Telescope using  which gave "2.8 km (2.8 km)". The result would now be "2.8 km (1.7 mi)". This is from Mike Peel's suggestion here.
 * Change of symbols used for dot and micro
 * Some units use a dot for a product or micro for . Until now, convert has used · (U+00B7 = interword separation = ) and µ (U+00B5 = micro sign) for these symbols.
 * Per discussions at Dots and Micro symbols and MOS ( permalink ), convert is changing to use ⋅ (U+22C5 = dot operator = ) and μ (U+03BC = Greek small letter mu).
 * In addition, the following dot/micro unit codes that are not used in articles have been removed. Alternative unit codes are available, but if any of these are needed, they can be added to Module:Convert/extra.
 * Using middot:
 * Using micro:
 * Using u or mu:
 * Formally, the Unicode name is . -DePiep (talk) 12:11, 8 December 2017 (UTC)
 * I very much like every change listed here. What is referred to as "some examples are unsatisfactory" are precisely what I regard as distinctly desirable, especially in the case of nested parentheses, because this sensitizes both editor and reader to the difficulty of interpreting the unit (and helps the confused reader who is not familiar with typical units used with the topic).  —Quondum 18:44, 8 December 2017 (UTC)


 * The new version is now live. Johnuniq (talk) 22:36, 9 December 2017 (UTC)

Unit documentation fixes
Many ambiguous  units, and many redundant   units were removed in January 2017. Would someone more patient than me please fix the following to remove the errors. They are obvious, but searching for "convert:" is a systematic way to find them. The first two of these links would be fixed by removing the deleted units from the second two of the links. Johnuniq (talk) 00:10, 10 December 2017 (UTC)
 * Template:Convert/list of units/area
 * Template:Convert/list of units/energy
 * Template:Convert/list of units/area/Middle Eastern
 * Template:Convert/list of units/energy/Btu
 * ✅ -- WOSlinker (talk) 11:41, 10 December 2017 (UTC)

Deprecated comma=gaps5
Hi, please can someone correct the guide for the template which doesn't clearly state that the variable for thousands seperator, gaps every 5 digits, is deprecated (i.e. ) and   should be used. --Waddie96 (talk) 11:59, 17 December 2017 (UTC)
 * Where did you find it is deprecated? - DePiep (talk) 13:13, 17 December 2017 (UTC)
 * The only thing I can find is WP:DIGITS, which says "generally grouped into threes". That does not deprecate groups of five. It also mentions the screen reader problem with gaps, but again that isn't deprecation and would apply equally to gaps3. Kendall-K1 (talk) 13:54, 17 December 2017 (UTC)
 * I don't recall the background, but  was deprecated in June 2015 (diff) in Module version 11. The fact that it is deprecated is shown by the asterisk in the following, and the obnoxious warning when previewing an edit with this example:
 * → 12345.67891 m
 * The current options are:

comma=5      only group if 5 or more digits (no comma in "1234.0") comma=gaps   use gaps, not comma, to separate groups of digits comma=gaps3  group only in threes (no gap before "5" in "1.2345") comma=gaps5  deprecated; now equivalent to comma=gaps comma=off    no commas in input or output numbers
 * Johnuniq (talk) 21:56, 17 December 2017 (UTC)
 * In the context of convert, I see no reason for supporting the display of up to 64-bit floating point values with anything but 3-digit grouping or no grouping, so deprecation of gaps5 makes sense. In the general MoS context, displaying values with 5-digit grouping should not be deprecated, but that is out of scope here.  —Quondum 22:28, 17 December 2017 (UTC)  Ignore my comment; I had the wrong end of the stick.  —Quondum 03:09, 18 December 2017 (UTC)
 * The discussion at the time is the first section here: Kendall-K1 (talk) 22:32, 17 December 2017 (UTC)
 * (ec) Don't see why or when should not follow MOS per se? -DePiep (talk) 22:37, 17 December 2017 (UTC)


 * ✅ adjusted documentation (gaps5=deprecated). -DePiep (talk) 22:37, 17 December 2017 (UTC)

Hair's breadth
As there is no "units noticeboard", this page may be a substitute. Editors may like to review an RfC:
 * Talk:Hair's breadth

Johnuniq (talk) 06:27, 19 December 2017 (UTC)


 * The article is not about a unit, but rather about an expression; a better title might have been By a hair's breadth. —Quondum 14:42, 19 December 2017 (UTC)

Convert/helper error
See Template_talk:Frac:


 * &rarr; ❌


 * &rarr; ❌


 * &rarr; ✅

It appears that module:Convert/helper does not recognise the first number form (correct by itself). I suggest to add this input option, or at least create an error (so that these situations can be categorised). -DePiep (talk) 11:01, 28 December 2017 (UTC)
 * That was puzzling because we have some tests at July 2017 where I obviously thought  was producing the correct output (12+3/8) but it shows only 3/8 at the moment (it will show the correct output when next purged). It turns out Module:Convert/helper was working correctly but an edit on 15 December 2017 to frac broke the module's regex. It is hard to make it bullet proof because most of the output from frac is span stuff, and if the module looks for exactly what frac should output, then the module would need to be changed whenever some tweak to frac occurred. I fixed the regex so it now handles   and put a quick test at Module talk:Convert/helper. I will probably tweak the module a bit more because it is failing the frasl test and one other, although the second is not a problem. Johnuniq (talk) 03:11, 29 December 2017 (UTC)
 * I have finished tweaking it for now. Johnuniq (talk) 04:41, 29 December 2017 (UTC)