User:Johnuniq/Using the convert module Source: en.wikipedia.org/wiki/User:Johnuniq/Using_the_convert_module

Module:Convert is ready to be considered as a replacement for the convert templates. This page shows what needs to be considered, and I hope people will comment at Template talk:Convert#Using the convert module or at the talk page here. Johnuniq (talk) 11:06, 16 September 2013 (UTC)

Proposal

Allow two weeks for further testing of the module, and to overcome the roadblocks below.
On an arranged date, say 1 October 2013, replace Template:Convert with Template:Convert/sandboxlua for an evaluation period.
If any serious problems arise that cannot be quickly resolved, restore the template.

MediaWiki developers want high-overhead templates replaced with modules and are not concerned about the impact on the servers from making changes like this.

Would the wikitext currently at Template:Convert work if moved to another name? That would allow comparisons between the current template and the module to be made after replacing Template:Convert with the module version.

See the convert documentation.

Roadblocks

Done All issues here are either fixed, or were ok in the first place. Johnuniq (talk) 21:59, 24 November 2013 (UTC)

The module may have problems which would need to be fixed before its use. These are documented here.

Templates dependent on convert

Are there any templates (such as infoboxes) that call the current Template:Convert, and which rely on a feature of that template that is not supported by the module?

Torque or energy

Update After finding a few hundred converts using constructs like the following, I decided to fix the module to accept certain energy units so they would convert to/from Nm, so the following examples now work. Johnuniq (talk) 22:37, 26 September 2013 (UTC)

The module requires the output and input units to have the same "type", where the type is a name assigned to the unit. For example, currently Nm is type "torque", and ftlb is type "energy". That means it is not possible to convert between those units:

{{convert|1200|Nm|ftlb|0|abbr=on|lk=on}} → 1,200 N⋅m (885 ft⋅lb)
{{convert/sandboxlua|1200|Nm|ftlb|0|abbr=on|lk=on}} → 1,200 N⋅m (885 ft⋅lb)
{{convert|1200|Nm|lbft|0|abbr=on|lk=on}} → 1,200 N⋅m (885 lb⋅ft)
{{convert/sandboxlua|1200|Nm|lbft|0|abbr=on|lk=on}} → 1,200 N⋅m (885 lb⋅ft)

If required, the module can make an exception for Nm. Is it required? Do any other units have the magic property of being a certain type in one conversion, and a different type in another conversion?

Population density

Update After finding a couple of converts that mix the following types (although there appears no reason to do so), I've decided to change all the "population density" units to "per unit area" so there is no restriction on converting between them. Before that change, the second example below gave an error. Johnuniq (talk) 02:16, 27 September 2013 (UTC)
{{convert|500|PD/sqmi|/km2}} → 500 inhabitants per square mile (190/km²)
{{convert/sandboxlua|500|PD/sqmi|/km2}} → 500 inhabitants per square mile (190/km²)

I'm not sure what should happen with units like these. Presumably, they should be of the same type so there is no dimension mismatch? That would allow conversions between any of the units listed at Population density and Per unit area.

Calorie or calorie

Update It looks like the module is correct. Johnuniq (talk) 21:59, 24 November 2013 (UTC)

WP:MOSNUM states that the symbol cal refers to a gram calorie, whereas Cal refers to a kilogram calorie.

The definitions used by the module need to be checked: search for "calorie" at Conversion data, and see the differences at the power testcases.

Convert/x

If required, articles using convert/x ({{Convert/2}}, {{Convert/3}}, {{Convert/4}}, {{Convert/f}}, {{Convert/flip}}, {{Convert/flip2}}, {{Convert/flip3}}, {{Convert/flip4}}, {{Convert/scale}}, {{Convert/spell}}) would need to be checked and possibly manually adjusted to use the module. In a small number of cases, a wording workaround would be required as the module does not support arbitrary join text between items in a range (only predefined terms like "to" are possible).

Any converts that use 0 to mean "use the default output unit" would need to be adjusted because the module always interprets 0 as a rounding precision.

Unit definitions

The units used by the module are defined at Conversion data. Nearly all the data was copied from the templates created by Jimp and it would not have been possible to develop the module without the extremely accurate and thorough unit definitions in the templates.

New units can be quickly added by editing Module:Convert/extra, but the conversion data page should be regarded as the master list of units.

Testcases

Many test pages, and an accompanying module were created by WOSlinker. The tests compare the outputs from the current Template:Convert with the output from Template:Convert/sandboxlua. Following is a summary of the results as at 16 September 2013.

acceleration ∙ equivalent
area ∙ 3 differences;^{[note 1]} 2 link disagreements
area2 ∙ 1 difference due to a newline in the template output
density ∙ equivalent except for the module failing to use nowrap in one case^{[note 2]}
energy ∙ equivalent
energy2 ∙ 4 differences due to a default output disagreement; the link disagreements are trivial as they go, via a redirect, to the same page
energy3 ∙ equivalent
energy4 ∙ equivalent
energyperlength ∙ several link disagreements
energypermass ∙ equivalent
energypervolume ∙ several link disagreements
exhaustemission ∙ equivalent
flow ∙ 3 minor differences (1 in the wikitext, 2 due to links); several link disagreements
force ∙ several link disagreements
fuelconsumption ∙ 4 template errors; several link disagreements
gradient ∙ equivalent
length ∙ equivalent
length2 ∙ two "micro" differences^{[note 3]}
lineardensity ∙ equivalent
mass ∙ minor differences and one template error^{[note 4]}
mole ∙ three "micro" differences^{[note 3]}
per ∙ 3 differences where the template uses "US gal" while the module uses "U.S. gal"; 2 link disagreements where template should link to pound (mass)
populationdensity ∙ 6 minor link disagreements
power ∙ 5 serious differences due to calorie vs. large calorie;^{[note 1]} 21 link disagreements
pressure ∙ equivalent
radioactivity ∙ equivalent
speed ∙ 2 template errors; 1 minor link disagreement
temperature ∙ 2 differences due to a rounding disagreement; 1 template error
change ∙ equivalent
time ∙ 2 module "unknown unit" errors^{[note 5]}
torque ∙ lots of differences; module needs to be fixed as indicated above, and some unit properties may need fixing in the module
volume ∙ several link disagreements
volume2 ∙ 2 differences where the module probably should include "imperial" in name/unit; 2 disagreements about "litre" vs. "liter"; several link disagreements
volume3 ∙ several link disagreements
volume4 ∙ 1 difference where the module probably should use plural "kennings"; several link disagreements
volume5 ∙ 1 difference where the module probably should use plural "kennings"; 4 link disagreements
misc ∙ 3 module "unknown unit" errors;^{[note 5]} 2 message differences; several link disagreements
warnings ∙ 4 different error messages
dualunit ∙ 1 difference due to a rounding disagreement
options ∙ 1 difference (template uses hyphen for minus); 13 template errors; 1 "US" vs. "U.S."
options2 ∙ 5 differences due to template using hyphen for minus; 2 differences are false positives;^{[note 6]} 5 template errors; 3 preunit disagreements; 4 differences due to the module using "US gal"; 1 link difference
tables ∙ differences regarding align right/center; template errors
spell ∙ many differences^{[note 1]}
range ∙ 6 differences^{[note 1]}

Notes

^ ^a ^b ^c ^d Opinions are needed regarding what the correct output should be. However, the module produces a satisfactory result and could readily be changed if something different is needed.
^ For the lb/in3 density unit, the symbol for cubic inch is "cu in" in the module, but is the more correct "<span class="nowrap">cu in</span>" in the template. The module output can be changed if agreed that the long symbol is wanted. What about other cubic inch occurrences?
^ ^a ^b For some units, the template (and WP:MOSNUM) uses "μ" (GREEK SMALL LETTER MU) where I think "µ" (MICRO SIGN) should be used. The module always uses MICRO SIGN, but also accepts MU for input.
^ Rounding disagreement; template links to pound instead of pound (mass); template links to grain (measure) which is a redirect to the grain (unit) used by the module; several other minor link disagreements; two different error messages for an invalid convert; one template error: {{convert|1|g|MTON}} is a dimension mismatch because g is mass while MTON is volume.
^ ^a ^b The module does not define some complex units handled by the templates. The units are horse year, note, spanner, wrench; none of these appear to be used. If needed these units could be added later.
^ The differences for {{convert|33|e9m3|e9cuft|adj=on|abbr=off}} and {{convert|1.23|e3m3|adj=on}} are due to the template using "-" for a hyphen. The template and module outputs are equivalent.

Module problems

It is likely that switching to the module would reveal several problems including unknown units. Editors may report quirks, or problems may be reported in the error categories:

Category:Convert invalid units ∙ Pages with an invalid unit in a convert are listed here.
Category:Convert invalid options ∙ Pages with an invalid option in a convert are listed here.

Only pages in the main (article) and template namespaces are listed in a category when a convert problem is detected.

In addition to the testcases, I have several thousand convert examples copied from various articles, and a test script shows that the module produces satisfactory results for these additional tests, so problems introduced by the module should be manageable.

Issues where the module is known to sometimes differ from the templates include use of   and whether a unit name should be singular or plural.

Template problems

Switching to the module may introduce problems, but the current templates have issues, some of which already show bad results in articles. It is possible that introducing the module would fix some existing problems, and that should be balanced against whatever new problems would be introduced.

Articles known to have convert problems are:

Banpo ∙ displays "Template:Convert/hect" due to use of "hect" instead of "ha" as a unit. There is no way to find such problems which may due to an expectation that a particular unit should exist, or may be due to a typo. Using the module, the article would be in the "unknown unit" category.
Barbarossa-class ocean liner ∙ displays "Template:Convert/Dual/LinAonDorSoff" due to problem with "{{convert|7000|-|9900|hp|abbr=on|lk=in|disp=or}}".
Dodge D Series ∙ displays several "Template:Convert/cu in" due to use of "cu in" instead of "cuin".
Fathom#Line length ∙ displays four occurrences of "Template:Convert/track/disp/2".
Frederick Wheeler#Major works ∙ displays "Template:Convert/X" due to incorrect "X" in a range; previewing a correction with "{{convert|30|x|22|ft|m|disp=output only|abbr=on|1}}" shows another error.
Iguazu Falls#Comparisons to other famous falls ∙ displays two results like "1,746 m³/s (61,660 cu ft)" where the output unit is missing "/s" due to a typo; since "/s" was intended for both input and output, the converted values are correct; the module would give a "dimension mismatch" error.
MISTRAM#Principles of Operation ∙ displays two occurrences of "Template:Convert/mm/s" due to undefined unit "mm/s".
Secure Digital#Physical size ∙ displays several "Template:Convert/LoffAinDnumberSoff".
Tactical development on the Western Front in 1917#Army 5 displays "10 knots (0.0032 mi)" (a dimension mismatch) due to typo ("{{convert|10|kn|mi}}" has "kn" instead of, presumably, "km").

Several other problems are shown at Convert notes.

[need_opinions-1] Opinions are needed regarding what the correct output should be. However, the module produces a satisfactory result and could readily be changed if something different is needed.

[nowrap-2] For the lb/in3 density unit, the symbol for cubic inch is "cu in" in the module, but is the more correct "<span class="nowrap">cu in</span>" in the template. The module output can be changed if agreed that the long symbol is wanted. What about other cubic inch occurrences?

[micro-3] For some units, the template (and WP:MOSNUM) uses "μ" (GREEK SMALL LETTER MU) where I think "µ" (MICRO SIGN) should be used. The module always uses MICRO SIGN, but also accepts MU for input.

[mass-4] Rounding disagreement; template links to pound instead of pound (mass); template links to grain (measure) which is a redirect to the grain (unit) used by the module; several other minor link disagreements; two different error messages for an invalid convert; one template error: {{convert|1|g|MTON}} is a dimension mismatch because g is mass while MTON is volume.

[unknown_unit-5] The module does not define some complex units handled by the templates. The units are horse year, note, spanner, wrench; none of these appear to be used. If needed these units could be added later.

[options2-6] The differences for {{convert|33|e9m3|e9cuft|adj=on|abbr=off}} and {{convert|1.23|e3m3|adj=on}} are due to the template using "-" for a hyphen. The template and module outputs are equivalent.

[note 1]

[note 2]

[note 3]

[note 4]

[note 5]

[note 6]