Wikipedia:Corrector's manual

There are many manuals of style in English Wikipedia. But if an editor even knows them all, then s/he is not necessarily good in fixing mistakes of another editors. This manual presents several mistakes which are not especially well-known. They either are not recognized as mistakes by most Wikipedians, or are not easy to fix properly, without adding further errors.

Fully automatic rules for fixing poor wikicode cannot exist. If the code's author is MoS-unaware, then s/he is not know what s/he is doing. You ever have to think, instead him/her. You also have to think after a blind button-pushing fixer who edited the article between the original author and you.

The aim of this manual is not only the manual itself. One day, a smart wikicode analyser will be created. This manual will help to identify common problems.

Before starting to fix
Before investing a considerable amount of your work to fixing errors, you should identify the reason of their presence. When numerous errors are present, there are roughly three common scenarios: an article was edited by competent (though MoS-unaware) editors; an incompetently-written article; and a severely degraded article. The last case does not necessary imply vandalism, but it implies existence of a much better revision in the edit history.

Links
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Spaced hyphen ⟨- ⟩
The ⟨- ⟩ (U+002D U+0020) character sequence, except inside &lt;math> and source codes, is a certain indicator of poor typography. It is quite common knowledge that ⟨ - ⟩ should be replaced with ⟨ – ⟩ (U+00A0 U+2013 U+0020), but should it, really? The answer is: yes, if the spaced en dash is appropriate in this place. There are other choices, though. The original author does not necessarily know that genuine hyphens may not be spaced, hence if there should be a hyphen, then just delete spaces. Another possibility is an unspaced dash, one of two its main varieties (⟨–⟩ or ⟨—⟩).

There is an observation that the hyphen-minus has a strong appeal to some of "keyboard layout-only" editors, who use it instead punctuational marks, sometimes not even remotely homoglyphic, such as colon. For texts like Punctuation- I am doing it wrong. the correct fix will be: "Punctuation: he is doing it wrong."

Unspaced hyphen ⟨-⟩
A construction word-word or, especially, word-number, may be perfectly correct. There are no clear-cut rule which specifies all appropriate uses of hyphens, but there are several cases of improper use: …
 * 1) Name-Name: replace with ⟨–⟩ (en dash)
 * 2) * Exception: compound names (both compound family names and multiple given names)
 * 3) * Exception: trademarks and organization names which are written with hyphen
 * 4) Location-Location: replace with ⟨–⟩ (en dash)
 * a distance, road, railroad, other route or communication
 * 1) Number-Number: actually, three separate cases:
 * 2) * A code (telephone number, ISBN, or so): replacement not needed; in some cases can be appropriate
 * 3) * A range: replace with ⟨–⟩ (en dash)
 * 4) * Subtraction notation: see below

Spurious dashes or other homoglyphs
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Letter ⟨x⟩
Aside of words and variables, there are two appropriate and one improper uses of ⟨x⟩. The improper one substitutes it for the multiplication sign. Examples of valid use of ⟨x⟩ as a placeholder include x86 and Windows 9x.

&lt;math> tag
The &lt;math> tag, also imprecisely referred to as LaTeX, is a powerful tool to make mathematical typesetting readable both on legacy and modern browsers, but it is not intended for general typesetting. In MathJax mode, it consumes both traffic and client's computational resources, as well as makes other undesirable effects. It should be used only if it is really necessary, not when the author is lazy to acquire some bits of HTML and Unicode.

When you see the code which clumsily attempts to emulate usual ASCII characters, something like  for an underscore, then it is certain that the original author does not understand what s/he is doing. Entire formula stuff inside &lt;math> and &lt;/math> has to be refactored in this case. Very likely, only parts of the expression needs &lt;math>, or the tag is not needed at all because it has to be formatted under general typesetting rules, not mathematical ones.

&lt;math>… + … \rightarrow …&lt;/math> is also never a good sign. Refer to WP:MOSCHEM and WP:MOSPHYS for instructions how reactions should be written in Wikipedia.

Minus sign ⟨−⟩: the symbol most susceptible to corruption
The minus sign has three valid representations: This pluralism contributes to the fact that this symbol suffers from editors' ignorance and clumsiness more than anything else. There are three lines of attack against it: In Wikipedia, you never can be sure that a horizontal stroke between numerals, variables, or other expressions, is actually a properly encoded minus sign.
 * ⟨−⟩ (also spelled ⟨ ⟩), the only correct in a bare wikicode;
 * ⟨-⟩, the only correct inside &lt;math>;
 * ⟨-⟩ again, in parser functions and certain templates.
 * Casual: approximating with ⟨-⟩
 * because of laziness and/or general cluelessness;
 * in botched conversions from &lt;math> to something else.
 * Miscorrection/cluelessness: intermixing with dashes ⟨–⟩: see above and thank drive-by typography fixers.
 * Esoteric exercises: replacements with non-breaking hyphens ⟨⟩, line drawing characters and other exotic symbols.

Asterisk ⟨*⟩ not necessarily is a botched multiplication sign
Asterisk is known to be mistakenly used for a multiplication sign. Before fixing, you should be aware about three things:
 * A postfix asterisk ($a*$) is a valid notation for dual space and conjugate transpose/Hermitian adjoint;
 * Infix and prefix asterisks have legitimate uses in mathematics, but its correct typography is represented by symbols (though, encoded as ordinary ASCII asterisk under &lt;math>) and  respectively;
 * ASCII asterisk may and should be used as a multiplication sign in source codes in computer languages which use it in this rôle.

Wording
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