I once read a memorable column (by Willam Safire) that talked about this. I ran across it in his book You Could Look It Up, which is a collection of his newspaper columns about language.
This one was first printed over 30 years ago, in 1984 – wow! time flies! – but I think it still rings pretty true.
I managed to find a scan of the original column:
If we can trust Grammar Girl's thoroughness of search, then her advice is sound:
Every style guide I checked, except the AP Stylebook, stated there
should be no spaces between an em-dash and the adjacent words. That
means it is a style choice. If you're writing for a newspaper,
magazine, or website that uses Associated Press style, put in the
I'm the woman from the video.
Saying 'tac' isn't silly at all. I grew up in a military family, so this was used regularly when speaking of a dash. Without getting into details, my father was in many fields where he was required to spell out commands via a speaking system, and they used tac. In school, we used 'dash'. Generally, I use tac when referring to ...
I have been searching for the same as the OP. More searching has revealed this in the U.S. Government Printing Office Style Manual (I have not read the whole of it, so I might be misinterpreting it):
16.17. Signatures, preceded by an em dash, are sometimes run in with last line of text.
There appears to be a PDF render of the ...
Em dashes can be used if allowed by your style guide (but don't use them too often). For example, this is what APA says:
First, when would you use an em dash? The Publication Manual (p. 97) notes that em dashes are “used to set off an element added to amplify or to digress from the main clause.” The em dash draws a reader’s attention, partly because of the ...
According to a reddit.com post, this usage “originates as a navy term for flag signalling”:
A tackline is a length of halyard approximately 6 feet long; the exact length depends upon the size of flags in use. The tackline is transmitted and spoken as tack and is written as a dash (hyphen) "-". It is used to avoid ambiguity. It separates signals or groups ...
According to the Chicago Manual of Style, you should drop the comma. See section 6.86: "In modern usage, if the context calls for an em dash where a comma would ordinarily separate a dependent clause from an independent clause, the comma is omitted." No word on commas that separate independent clauses from each other, however, which is the case that brought ...
Your example seems to refer to an epigraph, which is a short passage normally used at the start of a book or chapter. There is no "single" answer. It depends entirely on the style guide or in-house style manual. The Chicago Manual of Style (13.36) says that
An author may wish to include an epigraph—a quotation that is
pertinent but not integral to the ...
An ellipsis is used in a quote to convey that the speaker trails off.
An em dash is used in a quote to convey that the speaker is cut off, even if the speaker cuts him/herself off, as is the case in your second example.
If you must use something other than quotation marks for dialog, here is The Chicago Manual of Style (17th ed.) 6.91:
Em dashes are occasionally used instead of quotation marks to set off dialogue (à la writers in some European languages). Each speech starts a new paragraph. No space follows the dash.
—Will he obtain the necessary signatures?
—Of course he ...
First, it's not a hyphen; it's an em dash. We use it for:
Aposiopesis: where a sentence is ended suddenly because the speaker is too emotional or can't think of the right way to express something or just—
A stronger break than parentheses—inserting a clause in the middle of another though—but remaining with the same sentence.
Showing a change of thought, ...
In your example, the em dashes are used in pairs to set off parenthetical phrases. A parenthetical phrase is a clause that is inserted into the flow of an otherwise complete sentence as an "interruption" that adds additional information. If the parenthetical phrase is removed, the remaining words should form a full and complete sentence on their own.
Unicode now calls all of these "Dash" characters (meaning, they have the "Dash" property, not that their names mention dash):
U+002D - HYPHEN-MINUS
U+058A ֊ ARMENIAN HYPHEN
U+05BE ־ HEBREW PUNCTUATION MAQAF
U+1400 ᐀ CANADIAN SYLLABICS HYPHEN
U+1806 ᠆ MONGOLIAN TODO SOFT HYPHEN
U+2010 ‐ HYPHEN
U+2011 ‑ NON-BREAKING HYPHEN
U+2012 ‒ ...
A modern discussion of compound points
Following the lead of Nicholson Baker in a review of M.B. Parkes's Pause and Effect published in The New York Review of Books, Keith Houston, Shady Characters: The Secret Life of Punctuation, Symbols & Other Typographical Marks (2013) refers to the ;— combination as a semi-colash. Houston reports that this form of ...
Good catch - it shows careful reading. But consider that the story was published in 1846 (and probably written the year before). Today we might use either the semicolon or the em-dash (but not both). Typically, the part after a semicolon is a complete sentence - one that is closely related to the first part (also usually a complete sentence).
(I'm glad ...
For a view directly opposed to Wikipedia's, consider this entry from Words Into Type, Third Edition (1974):
Parentheses are used to enclose expressions that are of such a nature that they would not be sufficiently set off by commas or dashes. Many times dashes or parentheses are equally good style, but parentheses should preferably be reserved to enclose ...
There is no rule that prohibits the use of or to isolate clauses in your interrupting phrase:
A word group (a statement, question, or exclamation) that interrupts the flow of a sentence and is usually set off by commas, dashes, or parentheses.
Note: there are rules for using dashes, parentheses, and commas. See parentheses vs. double commas vs. dashes ...
(A coincidence of https://english.stackexchange.com/a/190692/8286 )
Just FWIW, I say "minus" like you ("l s minus a l") or often just don't say the minus. So, in the example I'd read "n c l p 1234"
IMO very few people say hyphen. I'd say "dash" is common, but I'd say "minus" is more common ...
hyphen "The short one"
Its diminutive size helps the reader to read the two words as a single word. Ideally, this would be visually invisible and the two words would be directly joined, but grammar rules don't agree.
en-dash "The mid-sized one"
The difference in appearance is important in order to signal to the reader that it should not be interpreted as a ...
In a maths context (at least within physics) in the UK, you would use "prime". If you didn't, you'd say something more specific, like "first derivative of x", as the prime can be used for other derived variables as well (e.g. x after an event, especially in lower level work)
A "dash" is a horizontal line, and isn't commonly used in mathematics as it's very ...
While spaces are not normally used with en dashes, and exception is often made in this case because without a space it can turn "2013–January" into a single visual unit, and so more closely bind these parts of the separate dates, than they are to the rest of the date they actually belong to.
We would not use spaces with partial dates like "June–August 2012",...
The "double hyphen" is a stand-in for an em dash (—), which is a punctuation usually used for expressing a pause before a related thought. Some of its functions are redundant with colons, semicolons, and even commas, although using it in place of a comma is typically frowned upon as unnecessary.
What you're dealing with in your greeting is an em dash taking ...
Dashes can be used in place of parentheses to indicate an aside or qualifying statement. I don't think either has a place in any of your examples.
Generally speaking, for the same reason you're having a hard time understanding their use, it's a good idea to avoid using semicolons altogether. The semicolon is intended to separate two sentences where the ...
Second, it's not a sentence.
What's the subject, what's the verb?
It's a complex adjective phrase (i.e, a reduced disjoined restrictive relative clause), with a couple of descriptive similes attached, after being introduced by like, like most similes.
The whole apparatus might well be what one would put after
This thing here [pointing] is ...
Unlike pure spelling and basic punctuation rules, the shape of punctuation marks and characters are governed only by style guide and personal practice. Some style guides even advise consistently using only three separate dots (never ellipses) and simple hyphens (never en dashes, em dashes, numeric dashes, or horizontal bars).
What level of typographic ...
Could you? Sure. But no, you shouldn't. Separate the sentences or move the clarification within.
I am wondering if you know any publications, blogs or websites -- particularly those interested in tech or the cloud, big data, mobile applications, info graphics, etc. -- who are seeking new writers right now?
I am wondering if you know any ...
Actually, the rules are fairly set on spaces before or after an "em-dash" -- you don't use them. If your style guide calls for spaces around a dash, you use a different character altogether, the "en-dash."
Wikipedia has a descent overview on dashes, especially noting the differnet ways to reflect either and em-dash or an en-dash.
An em-dash can be written ...