Module talk:String

How to do string.replace of level3 headers in transcluded wikitext

I am trying to use replace to strip out the level3 headers from a transclusion of Dublin North-West (Dáil constituency)#TDs.

However {{#invoke:String|replace|{{trim|{{#section-h:Dublin North-West (Dáil constituency)|TDs}}}}|%=%=%=[^%=]*%=%=%=||plain=false}} leaves the level3 headers in place -- see my /sandbox test page at special:permalink/1164910747

Any suggestions? Feel free to edit that sandbox if it helps. BrownHairedGirl (talk) • (contribs) 21:13, 11 July 2023 (UTC)

I have never seen the #section-h construction before. Would you mind explaining where that comes from? — Martin (MSGJ · talk) 21:50, 11 July 2023 (UTC)

See Help:Labeled section transclusion. * Pppery * _{it has begun...} 22:09, 11 July 2023 (UTC)

Turns out this has nothing to do with Lua: when using an equals sign in an argument to a template or module you need to name the parameter explicitly or escape it with {{=}}: {{#invoke:String|replace|{{trim|{{#section-h:Dublin North-West (Dáil constituency)|TDs}}}}|pattern=%=%=%=[^%=]*%=%=%=|replace=|plain=false}} should work. * Pppery * _{it has begun...} 22:09, 11 July 2023 (UTC)

Bless you @Pppery. That's done it. Thanks also to @Trappist the monk for appplyig the fix to my sandbox -- I am not sure which of you did what first, but you have both been a great help, and mighty promptly.

I case you are curious, this is for my development of the {{Constituency Teachtaí Dála navbox}} meta-template. When I used it to make {{Kerry (Dáil constituency)/TDs}}, the level3 headers were an annoying intrusion, but now I can make 'em vanish from the navbox. Thanks again. BrownHairedGirl (talk) • (contribs) 22:35, 11 July 2023 (UTC)

This isn't quite what you were asking, but related enough you might be interested in it: {{Conditional heading}}. Mathglot (talk) 04:50, 12 July 2023 (UTC)

Thanks, @Mathglot. I want to remove the headings rather than to promote or demote them, so it's not what I need in this case. But it's good to know about this, for future refrence. BrownHairedGirl (talk) • (contribs) 23:11, 12 July 2023 (UTC)

Protected edit request on 21 September 2023

On Latin Wikipedia I have created a tiny module named Module:Translitteratio, which contains a single function named abecedaria. The function accepts three parameters and works exactly like the translit M4 macro (but with the order of arguments changed to chars, replacement, string). For example,

{{#invoke:translitteratio|abecedaria|aeiou|äëì|Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam mollis, metus ac volutpat auctor, sem ligula interdum nulla, ac pellentesque nibh erat sed nisi. Integer nec auctor orci. Quisque nibh metus, viverra et viverra nec, laoreet in mi. Integer aliquet, mauris vitae tristique fringilla, ante odio ultrices quam, et fermentum orci purus nec lorem. Integer quis vehicula arcu, et laoreet enim. Nulla euismod neque velit, eget iaculis massa tempor ut. Nulla convallis maximus neque et porttitor. In nunc eros, convallis id posuere ac, egestas et arcu. Aenean faucibus sollicitudin ipsum, in condimentum mauris maximus in. Etiam facilisis eros vel tortor tincidunt iaculis. Vestibulum lorem lectus, posuere sed enim in, varius pharetra lorem. Morbi nisl lacus, eleifend ut urna vitae, interdum consequat ipsum. Cras ut imperdiet ante. Sed quis luctus purus, quis porta erat. Ut gravida gravida augue a euismod.}}

generates

Lrëm ìpsm dlr sìt ämët, cnsëctëtr ädìpìscìng ëlìt. Näm mllìs, mëts äc vltpät äctr, sëm lìglä ìntërdm nllä, äc pëllëntësqë nìbh ërät sëd nìsì. Intëgër nëc äctr rcì. Qìsqë nìbh mëts, vìvërrä ët vìvërrä nëc, lärëët ìn mì. Intëgër älìqët, märìs vìtäë trìstìqë frìngìllä, äntë dì ltrìcës qäm, ët fërmëntm rcì prs nëc lrëm. Intëgër qìs vëhìclä ärc, ët lärëët ënìm. Nllä ëìsmd nëqë vëlìt, ëgët ìäclìs mässä tëmpr t. Nllä cnvällìs mäxìms nëqë ët prttìtr. In nnc ërs, cnvällìs ìd psërë äc, ëgëstäs ët ärc. Aënëän fäcìbs sllìcìtdìn ìpsm, ìn cndìmëntm märìs mäxìms ìn. Etìäm fäcìlìsìs ërs vël trtr tìncìdnt ìäclìs. Vëstìblm lrëm lëcts, psërë sëd ënìm ìn, värìs phärëträ lrëm. Mrbì nìsl läcs, ëlëìfënd t rnä vìtäë, ìntërdm cnsëqät ìpsm. Cräs t ìmpërdìët äntë. Sëd qìs lcts prs, qìs prtä ërät. Ut grävìdä grävìdä ägë ä ëìsmd.

(You can experiment with it in the Latin Wikipedia sandbox page)

This allowed to write the {{la:Sine notis diacriticis}} template, which transforms vowels with various accents into simple vowels, and the {{la:Ufrac}} template, which writes fractions using only Unicode characters (no HTML).

I think that Module:String would benefit from this function, with its name changed from abecedaria to translit.

Translated into English, the code to add to this module would be:

str.translit = function( frame )

	local args = frame.args

	if args[1] == nil or args[1] == '' or args[3] == nil or args[3] == '' then
		return ''
	end

	local npairs
	local text = mw.text.split(args[3], '', true)
	local removenda = mw.text.split(args[1], '', true)
	local substituenda

	if args[2] ~= nil then
		substituenda = mw.text.split(args[2], '', true)
	else
		substituenda = {}
	end

	if #removenda > #substituenda then
		npairs = #substituenda
	else
		npairs = #removenda
	end

	for idx1 = 1, npairs do
		for idx2 = 1, #text do
			if text[idx2] == removenda[idx1] then
				text[idx2] = substituenda[idx1]
			end
		end
	end

	for idx1 = npairs + 1, #removenda do
		for idx2 = 1, #text do
			if text[idx2] == removenda[idx1] then
				table.remove(text, idx2)
			end
		end
	end

	return table.concat(text)

end

return str

Grufo (talk) 17:40, 21 September 2023 (UTC)

This feels sufficiently obscure that it doesn't belong in this module, unless some actual use case can be presented here unrelated to what other wikis do. * Pppery * _{it has begun...} 22:02, 21 September 2023 (UTC)

What is obscure, what it does or its code? What it does is well explained by the documentation of M4's translit (this is just a clone). As for what can be done with it, I believe template {{la:Ufrac}} has no languages. --Grufo (talk) 01:28, 22 September 2023 (UTC)

Yes, and why should we care? Why is the Unicode system for fractions superior to the one currently in use? Why should we invent more ways to do the same thing? * Pppery * _{it has begun...} 01:33, 22 September 2023 (UTC)

I believe this discussion started with the wrong foot. This is a generic function proposal, it is not a proposal about the {{la:Ufrac}} template. In fact, the other template that uses this proposal ({{la:Sine notis diacriticis}}) does something completely different (i.e. removing accents from vowels). I have no problem answering questions about {{la:Ufrac}}, but I would kindly ask you to stay on topic on this function proposal. Re: Why should we invent more ways to do the same thing? Because there are many cases where you have no alternatives. For instance, you can write,

• 100 {{Abbr|carats|A carat is ¹⁄₁₇₂₈ of a pound.}}

  ↳ 100 carats

but you cannot use the CSS/HTML solution used by {{Fraction}} inside {{Abbr}}. But again, since it is a generic function proposal, frankly I think it will find most of its applications in the transliteration of alphabets rather than in fractions (that was indeed only one example). It is such a basic functionality that it has been part of Unix since the old days. For instance, if you look at the code of {{la:Ufrac/par}} you will find

{{#invoke:translitteratio|abecedaria|0123456789|⁰¹²³⁴⁵⁶⁷⁸⁹|{{{1}}}}}

All that does is mapping each digit to its superscript unicode character. If we wanted to do the same using {{#invoke:string|replace}} we would need ten module invocations. --Grufo (talk) 01:55, 22 September 2023 (UTC)

We already have Module:MultiReplace for that. Yes, the syntax you used is slightly terser than that module's syntax, but there's no need to shake up the world. * Pppery * _{it has begun...} 02:09, 22 September 2023 (UTC)

I have not done a speed test, but I suspect that syntax will not be the only thing where this function will greatly beat Module:MultiReplace. In fact, I suspect that performance will be tremendously less expensive here. This function is less powerful (the mapping happens verbatim character by character), hence, exactly for this reason, it is possible to map without problems strings that are page-long – while I suspect that Module:MultiReplace will break the servers in that case. If all this seems unrealistic, think about the amount of Unicode characters: just to map four types of accents in {{la:Sine notis diacriticis}} I had to write the following string:

ĀĒĪŌŪȲĂĔĬŎŬÀÈÌÒÙỲÁÉÍÓÚÝÂÊÎÔÛŶāēīōūȳăĕĭŏŭàèìòùỳáéíóúýâêîôûŷ̄̆

I assure you, there can be way more complex transliterations than this. And last but not least: in terms of both computational complexity and ease of use, what you call “shaking up the world” is rather a going back to the old days. --Grufo (talk) 02:26, 22 September 2023 (UTC)

Yes, and do we really care? Don't make speculative claims about breaking the servers - see WP:PERF. I'm still not convinced that we need any of this level of complexity instead of just letting people type what they want to type rather than relying on templates to fix it for them and it's clear we won't convince each other at this point. * Pppery * _{it has begun...} 02:33, 22 September 2023 (UTC)

Fine. Continuing with this spirit interface-wise Latin Wikipedia will soon beat English Wikipedia. --Grufo (talk) 02:41, 22 September 2023 (UTC)

Protected edit request on 25 October 2023

Please, add r to the word fist (resulting in first), line number 61. Nishimoto, Gilberto Kiyoshi (talk) 18:11, 25 October 2023 (UTC)

Protected edit request on 3 September 2024

All of the Lua pseudo-regex special characters are in the ASCII range. See en:UTF-8#Encoding. Therefore, we don't need at all to use the (costly) mw.ustring.* functions in some parts I have reviewed.

My request is to replace:

function str._escapePattern( pattern_str )
	return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" )
end

with:

function str._escapePattern( pattern_str )
	return ( string.gsub( pattern_str, "[%(%)%.%%%+%-%*%?%[%^%$%]]", "%%%0" ) )
end

(I am also removing the capture group, which is unneeded as we can use the "%0" whole capture)

(edit: I am also taking the opportunity, for extra robustness, to add parentheses in order to discard the 2nd value (number of replacements) returned by these gsub() functions, then subsequently by _escapePattern(). The more I encounter this "multiple values returned" Lua feature, the more I think it was a terrible design idea)

Second change: line 409, we can similarly replace:

replace = mw.ustring.gsub( replace, "%%", "%%%%" ) --Only need to escape replacement sequences.

with:

replace = string.gsub( replace, "%%", "%%%%" ) --Only need to escape replacement sequences.

These changes would significantly decrease the overhead of having the "plain mode" enabled in this module's functions.

Od1n (talk) 03:26, 3 September 2024 (UTC)

1243840019, thanks. Od1n (talk) 22:38, 3 September 2024 (UTC)

Protected edit request on 18 October 2024

The value returned by a module function must always be a string, however some functions here return numbers (these are len, str_find, find and count). Could you please apply this diff? You can just copy and paste the code at this permanent link.

Although unnoticeable when used in normal wikitext, this can create problems when Module:String is invoked using other modules.

For instance, focusing on the len function, for each argument passed, a template named mytemplate containing the following code

{{#invoke:params|mapping_by_invoking|string|len|mapping_by_replacing|^.*$|%0 mod 3|1|for_each|[$#:$@]}}

should print [PARAMETER-NAME:LENGTH-OF-PARAMETER mod 3]

The code above invokes {{#invoke:string|len|...}} for each parameter passed. Then it attempts to replace the lengths saved with %0 mod 3, i.e. by adding  mod 3 at the end of each parameter. And so, for instance, {{mytemplate|hello|world|foo|bar}} should print

[1:5 mod 3][2:5 mod 3][3:3 mod 3][4:3 mod 3]

However, since {{#invoke:string|len|...}} returns a number, any attempt to do string manipulation with the number returned will generate an error. --Grufo (talk) 05:17, 18 October 2024 (UTC)

 Not done: The value returned by a module function must always be a string is not true. mw:Extension:Scribunto/Lua reference manual#Returning text states The module function should usually return a single string; whatever values are returned will be passed through tostring() and then concatenated with no separator. Further, when calling a module function from other Lua code even that doesn't apply; in that case it's like any other Lua function. I also note this change may well break other code that calls these functions (if it for some reason calls functions from this module instead of calling Scribunto's string manipulation functions directly) that expect a number from len or the like. Anomie⚔ 11:12, 18 October 2024 (UTC)

Alright, it seems then that I will have to fix that in {{#invoke:params|mapping_by_invoking}} and stringify whatever modules may return. --Grufo (talk) 13:35, 18 October 2024 (UTC)