Llinell doriad

Marc atalnodi yw **llinell doriad** (Saesneg: *dash*) sy'n hirach na chysylltnod a chyda defnydd gwahanol. Y mathau mwyaf cyffredin o linellau toriad yw'r llinell doriad èn (–) a'r llinell doriad èm (—).

## Llinellau toriad cyffredin
Mae sawl math o linell doriad; y mwyaf cyffredin yw:

### Cysylltnod
Defnyddir **cysylltnod**   i uno geiriau ac i wahanu sillafau. Nid yw cysylltnod yn wirioneddol yn llinell doriad; mae gosod teip gofalus (gan gynnyws gyda rhaglenni cyfrifiadur cyfoes, megis prosesydd geiriau a HTML) yn dibynnu yn hytrach ar y llinellau toriad cywir canlynol.

### Llinell doriad ffigur
Caiff **llinell doriad ffigur**  ei enw gan ei fod yr un lled a ffigur, mewn ffurfdeipiau lle mae'r ffigurau o led cyfartal o leiaf.

Defnyddir llinell doriad ffigwr pan mae'n rhaid defnyddio llinellau toriad o ffewn ffigurau, er enghraifft gyda rhifau ffôn: *8675309*. Nid yw hyn yn dangos amrediad (defnyddir llinell doriad en ar gyfer gwneud hynny), na ffwythiant fel y minws (sydd gyda glyff ei hun).

Nid yw'r llinell doriad ffigwr wastad ar gael; yn yr achos hon, dylid defnyddio llinell doriad minws yn ei le. Y cyfeirnod Unicode ar gyfer llinell doriad ffigwr yw  (degol 8210). Rhaid i awduron HTML ddefnyddio'r ffurf rhifol `&amp;#8210;` neu `&amp;#x2012;` i'w deipio os nad ydy'r ddogfen yn Unicode; nid oes endid nod cywerth. Yn TeX, nid oes gan y ffont safonol linell doriad ffigwr; ond, mae gan y rhan fwyaf o ffigurau'r un lled â llinell doriad èn, felly gellir defnyddio hwnnw yn ei le yn TeX.

### Llinell doriad en
Mae **llinell doriad èn**, neu **llinell doriad n**, (–) tua'r un lled a'r lythyren *n*. Mae hanner maint llinell doriad èm. 

Defnyddir y llinell doriad èn i ddynodi amrediad, megis *6–10 blwyddyn*, ac fe'i darllenir fel "chwech i ddeg blwyddyn".

#### Amrediadau o werthoedd
Defnyddir llinell doriad èn yn gyffredin i ddynodi amrediad caëedig o werthoedd (amrediad sydd wedi ei ddiffinio'n glir heb ffiniau is nac uwch sy'n anfeidraidd), megis amrediad rhwng dyddiadau, amserau, neu rhifau.

Rhai enghreifftiau o'r defnydd:
* Mehefin – Gorffennaf 1967
* 9:00 – 10:00 y bore
* Ar gyfer plant oedran 3–5
* tud. 38–55
* Arlywydd Jimmy Carter (1977–1981)

Mae'r *Guide for the Use of the International System of Units (SI)* yn argymell y dylid y gair *i* gael ei ddefnyddio yn hytrach na llinell doriad èn pan y gall amrediad rhifol gael ei gamddeallt fel tynnu, megis mewn amrediad o unedau. Er enghraifft, "foltedd o 50 V i 100 V" yn hytrach na "foltedd o 50 – 100 V".

Cysidrir yn anaddas i ddefnyddio llinell doriad èn yn lle'r geiriau *i* ac *a* mawn brawddegau sy'n dilyn y ffurf *o ... i ...* a *rhwng ... a ...*.  That is, the *Chicago Manual of Style* rules specify  llinell doriad en in these:
* Notre Dame beat Miami 31–30.
* New York–London flight.
* The Supreme Court voted 5–4 to uphold the decision.

but hyphens in these:

* Mother-daughter relationship
* The McCain-Feingold bill
* A C-C single bond
* Taft-Hartley Act
* Bose-Einstein statistics

#### Ansoddeiriau cyfansawdd
Gellir defnyddio llinell doriad en yn hytrach na chysylltnod mewn ansoddeiriau cyfansawdd pan mae un rhan yn cynnwys dau air neu un gair cyplysedig:

Traditionally an em dash—like so—or a spaced llinell doriad em — like so — has been used for a dash in running text. *The Elements of Typographic Style* recommends the more concise spaced  llinell doriad en – like so – and argues that the length and visual magnitude of an llinell doriad em "belongs to the padded and corseted aesthetic of Victorian typography." The spaced  llinell doriad en is also the house style for certain major publishers (Penguin, Cambridge University Press, and Routledge among them). However, some longstanding typographical guides such as *The Chicago Manual of Style* still recommend unspaced em dashes for this purpose. The *Oxford Guide to Style* (2002, section 5.10.10) acknowledges that this style is used by "other British publishers", but observes that Oxford University Press (OUP) does not use it. In practice, there is little consensus, and it is a matter of personal neu house taste.

The  llinell doriad en (always with spaces, in running text) and the *spaced* llinell doriad em both have a certain technical advantage over the *unspaced* em dash. In most typesetting and most word processing, the spacing between words is expected to be variable, so there can be full justification. Alone among punctuation that marks pauses neu logical relations in text, the *unspaced* llinell doriad em disables this for the words between which it falls. The effect can be uneven spacing in the text.

En dashes are often preferred to em dashes when text is set in narrow columns (as in newspapers and similar publications).

The *spaced* llinell doriad em risks introducing excessive separation of words: it is already long, and the spaces increase the separation. In full justification, the adjacent spaces Mai be stretched, and the separation of words is further exaggerated.

### Bar llorweddol
The **bar llorweddol** neu *quotation dash*  is used to introduce quoted text. This is the standard method of printing dialogue in some languages (see the quotation dash section of the Quotation mark article for further details of how it is used).

If the quotation dash is unavailable, then the llinell doriad em can be used instead. In Unicode, the quotation dash is U+2015 (decimal 8213). In HTML, it can be input only with the numeric form, `&amp;#x2015;` neu `&amp;#8213;`; there is no equivalent character entity. But  for web pages one generally uses the em dash. There is no support in the standard TeX fonts, but one can use `\hbox{}\kern-.5em` instead (or just use an em dash).

### Llinell doriad wedi siglo
The **llinell doriad wedi siglo** (\sim neu ~) resembles a lengthened tilde, and is used to separate alternatives neu approximates. In dictionaries, it is frequently used to stand in for the defined term in example text. This character was added since Unicode 4.0.0. Note that there are several similar characters: ⁓ (U+2053: SWUNG DASH, used in Western typography), ∼ (U+223C: TILDE OPERATOR, used in mathematics), and 〜 (U+301C: WAVE DASH, used in East Asian typography).

Example:
* henceforth (adverb), from this time forth; from now on; **"\sim she will be known as Mrs. Smith"**.

The llinell doriad wedi siglo in Unicode is U+2053 (decimal 8275). In HTML, it can be input only with the numeric form, `&amp;#x2053;` neu `&amp;#8275;`; there is no equivalent HTML entity.

In LaTeX2ε, one can use the math mode command `$\sim$`, which yields the tilde operator, a similar character.

In Japanese a similar character, the wave dash is used instead, for a variety of purposes:
* to indicate an extension of a vowel in slang;
* it is often used in Japanese and Korean in place of an en dash;
* in Chinese, the wave dash and the llinell doriad em can be used interchangeably to express a range.

## Nodau eraill sy'n debyg i llinell doriad
Mae sawl nod arall sy'n edrych yn debyg i llinell doriad, ond mae gennynt ystyr a defnydd gwahanol. Mae rhain yn cynnwys:
* **Cysylltnod-minws** (-), Unicode U+002D, hwn yw'r cysylltnod safonol ASCII. Mae'n edrych fel llinell doriad, ond dylid ei ddefnyddio yn unig pan nad yw'r llinell doriad cywir ar gael. Defnyddir mewn grwpiau weithiau i ddynodi gwahanol fathau o linellau toriad.
* **Tilde** (~), U+007E, marc diacritig.
* **Tanrhic** (_), U+005F, (Saesneg: *Underscore*) sydd ynteu yn farc diacritig, neu yn nod sy'n cymryd lle bwlch safonol.
* **Macron** , U+00AF, marc diacritig arall.
* **Cysylltnod meddal** (U+00AD) sy'n cael ei ddefnyddio i ddangos lle gall linell dorri, megis mewn geiriau cyfansawdd neu rhwng sillafau.
* **Cysylltnod** , U+2010, nod sydd, yn wahanol i'r cystylltnod ASCII, *wastad* yn cynyrchioli cysylltnod.
* **Cysylltnod bwled** , U+2043, llinell fer llorweddol a ddefnyddir fel pwynt bwled mewn rhestrau.
* **Minws** (−), U+2212, `&amp;minus;`, sy'n weithredydd rhifyddeg a ddefnyddir mewn mathemateg i gynnyrchioli tynnu neu rifau negyddol.
* **Llinell doriad ton** , U+301C, a'r **Llinell doriad tonnog** , U+3030, sy'n linellau tonnog a chaiff eu canfod mewn setiau nodau Asiaidd Dwyreiniol. Yn deipograffegol, maent yr un lled ac un cell nod CJK (ffurf lled llawn), ac yn dilyn cyfeiriad y teip (yn llorweddol neu'n fertigol ar gyfer teip colofn). Defnyddir hwy fel llinellau toriad, ac weithiau fel amrywiolyn pwysleisiol o'r marc ymestyn llafariad katakana.
* **Cysylltnod Armeniaidd** , U+058A, sy'n gysylltnod yn yr wyddor Armeniaidd.
* **Maqaf Hebreaidd** , U+05BE, sy'n nod tebyg i gysylltnod yn yr wyddor Hebreaidd.
* **Cysylltnod todo Mongoliaidd** , U+1806, sy'n gysylltnod yn yr wyddor Mongoliaidd.
* **Hangul Jungseong Eu** ( U+3161 neu  U+1173) a ddefnyddir yn aml yn y Gorëeg i ddynodi'r sain .
* **Chōonpu Siapaneaidd** , U+30FC, a ddefnyddir yn Siapaneg i ddynodi llafariad hir.
* **Yī/ichi** , U+4E00, sy'n nod Tseiniadd sy'n golygu "un" yn Tsieinëeg a Siapaneg.

## Gosod llinellau toriad ar gyfrifiaduron
Yn draddodiadol, roedd gan deipiaduron a chyfrifiaduron set llythrennau cyfyngedig, yn aml heb allwedd i greu llinell doriad. Fel canlyniad, mae wedi dod yn gyffredin i amnewid am y nod neu'r pwynt atalnodi anghywir sydd agosaf at llinell doriad. Cynrychiolir llinell doriad em yn aml gan bâr o fylchau oamgylch un cysylltnod-minws (defnydd Prydeinig arferol) neu gan bâr o fylchau oamgylch dau cysylltnod-minws (yn yr Unol Daleithiau'n bennaf).

Modern computer software typically has support for many more characters, and is usually capable of rendering both the en and em dashes correctly—albeit sometimes with a little inconvenience for the user who has to input them. Some software, though, Mai operate in a more limited mode. Some text editors, for example, are restricted to working with a single 8-bit character encoding, and when unencodable characters are entered (e.g., by pasting from the clipboard), they are often blindly converted to question marks. Sometimes this happens to em and en dashes, even when the 8-bit encoding supports them, neu when an alternative representation using hyphen-minuses would seem to be an option.

Any kind of dash can manifest directly in an HTML document, but HTML also allows them to be entered as character entity references. The entity names for the llinell doriad em and the  llinell doriad en are mdash and ndash; therefore, they can be referenced in HTML as `&amp;mdash;` and `&amp;ndash;`. The equivalent numeric character references are `&amp;#8212;` and `&amp;#8211;`. Nearly all web browsers and operating systems used today are capable of rendering the numeric form, and almost as many correctly display the named form.

* In **Unicode**, the figure dash, en dash, em dash, quotation dash, and llinell doriad wedi siglo correspond to characters U+2012, U+2013, U+2014, U+2015, and U+2053, respectively.

* In **Mac OS** using the Australian, British, Canadian, German, Irish, Irish Extended, Russian, U.S., neu U.S. Extended keyboard layout, an  llinell doriad en can be obtained by typing option-hyphen, while an llinell doriad em can be typed with option-shift-hyphen.

* In **TeX**, an llinell doriad em is typed as three hyphens ("---"), an  llinell doriad en as two hyphens ("--"), and a hyphen-minus as one hyphen ("-"). Mathematical minus is signified as "$-$".

* Under recent versions of **X11**, you can obtain the *em dash* (—) by pressing the Compose key followed by - - - (triple hyphen-minus), and the *en dash* (–) can be obtained by pressing the Compose key followed by - - . (hyphen-minus, hyphen-minus, dot). In the absence of a compose key, it can be emulated by remapping some other seldom used key.http://process-of-elimination.net/wiki/Means_of_Composing_Accented_Characters_in_X_Window_System 

* On **Plan 9** systems, an en neu llinell doriad em Mai be entered by pressing the Compose key (usually left Alt), followed by typing en neu em respectively.

* In **Microsoft Windows**, an llinell doriad em can be typed with ctrl + alt + numeric hyphen (on the numeric keypad, usually in the top-right corner), and an  llinell doriad en can be typed with ctrl + numeric hyphen. This will not work with the hyphen key on the main keyboard (usually between "0" and "="), which has completely different functions. Alternatively, an en neu llinell doriad em Mai be typed into most text areas by holding down the Alt key and pressing 0150 neu 0151 respectively. The numbers must be typed on the numeric keypad with num lock turned on.

* With **Microsoft Word**'s default settings (both Windows and Macintosh versions), an llinell doriad em symbol (not always a true llinell doriad em from the font) is automatically produced by Autocorrect when two unspaced hyphens are entered between words ("word--word"). An  llinell doriad en (again, not always a true  llinell doriad en from the font) is automatically produced when one neu two hyphens surrounded by spaces are entered: ("word - word") neu ("word -- word"). This feature can be disabled by customising Autocorrect. Other dashes, spaces, and special characters are possible, found through Tools → Customize… → Keyboard… → Common Symbols. Unassigned symbols (such as the true minus sign) can be assigned keyboard shortcuts through Insert → Symbol… → (select desired symbol) → Shortcut key… . To determine if the true en neu llinell doriad em from the font are being used rather than a crossreferenced character from the Symbol font, copy and paste samples of the dashes into a text editor such as Windows Notepad. Using the true dash is important if one ever needs to share documents with other users in other applications neu operating systems.

In professionally printed documents, a typographer sometimes adds hair space, or, rarely, a full inter-word space, on either side of an em dash. In HTML it is possible to generate a hair space using the numeric character reference `&amp;#8201;`, but current-generation web browsers are not uniformly supportive of this character, and Mai render it incorrectly.

## Gweler hefyd
*Atalnodi

## Cyfeiriadau
## Dolenni allanol
* Chicago Style Q&A — Hyphens, En Dashes, Em Dashes
*  Peter K. Sheerin, The trouble with EM 'n EN
*  Dashes and Hyphens 
*  Colons, Semicolons, and Em-dashes 
*  Commonly confused characters
*  

Categori:Atalnodi
Categori:Teipograffeg