| 词条 | Hyphen-minus |
| 释义 |
The hyphen-minus (-) is a character used in digital documents and computing to represent a hyphen (‐) or a minus sign (−).[1] It is present in Unicode as code point {{nobr|{{unichar|002D|HYPHEN-MINUS}}}}; it is also in ASCII with the same value. DescriptionThe use of a single character for both hyphen and minus was a compromise made in the early days of fixed-width typewriters and computer displays.[2] However, in proper typesetting and graphic design, there are distinct characters for hyphens, dashes, and the minus sign. Usage of the hyphen-minus nonetheless persists in many contexts, as it is well-known, easy to enter on keyboards, and in the same location in all common character sets. As the minus signMost programming languages, restricting themselves to 7-bit ASCII, use the hyphen-minus, rather than the Unicode character {{unichar |2212|MINUS SIGN|nlink=Plus_and_minus_signs#Minus_sign}}, for denoting subtraction and negative numbers.[3][4] The minus sign is nominally the same width as the plus sign. In proportional typefaces it is longer than a hyphen. During typesetting a word wrap may also occur following a hyphen-minus, unlike the minus sign proper which is treated as a mathematical symbol. These differences make "-" as a substitute for minus signs undesirable in professional typography. Other usesOn typewriters, it was conventional to use a pair of hyphens to represent an em dash, and this convention is still sometimes used in computer text. The hyphen-minus is often used to represent an en dash, which may be used to indicate ranges (such as a time range of "2000–2004"), direction (as in "The Los Angeles–London flight"), and other cases of connection. The en dash is normally longer (the width of a letter "n") than a hyphen, though in a fixed-pitch or typewriter font there is no difference. The hyphen connects closely, the en dash less closely, while the em dash (the width of a letter "m") separates.[5]{{Failed verification|date=January 2019|reason=Source doesn't say the em dash "separates"}}. See also
References1. ^{{cite book |title=Unicode explained |author=Jukka K. Korpela |publisher=O'Reilly |year=2006 |isbn=978-0-596-10121-3 |page=382 |url=https://books.google.com/books?id=PcWU2yxc8WkC&pg=PA382}} {{Typography terms|state=collapsed}}{{DEFAULTSORT:Hyphen-Minus}}2. ^{{cite journal |author-last=Fischer |author-first=Eric |title=The Evolution of Character Codes, 1874-1968 |url=http://www.trafficways.org/ascii/ascii.pdf |access-date=2016-11-16}} 3. ^{{cite journal |author-last=Ritchie |author-first=Dennis |author-link=Dennis Ritchie |title=C Reference Manual |date=c. 1975 |url=https://www.bell-labs.com/usr/dmr/www/cman.pdf |access-date=2016-12-07}} 4. ^{{cite web |url=https://www.haskell.org/definition/haskell2010.pdf |title=Haskell 2010 Language Report |access-date=2016-12-07}} 5. ^{{cite web|title=Hyphens, En Dashes, Em Dashes|url=http://www.chicagomanualofstyle.org/qanda/data/faq/topics/HyphensEnDashesEmDashes/faq0002.html|website=The Chicago Manual of Style Online|accessdate=25 January 2017}} 2 : Punctuation|Typographical symbols |
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