Does HN markdown understand — or ‘?

EDIT: Nope.

It doesn't need to. You can put the mdash directly in comments: —

As opposed to regular dash: -

Well, since my keyboard doesn't have an mdash key, if there's no support for something like — or --- then I can't use mdashes.

At least on the US keyboard, Mac OS lets you input all three dash types.

Hitting the button to the right of [0] outputs a hyphen ("-"). Holding alt/option when hitting it will output an en dash ("–"), holding both alt/option and shift will output an em dash ("—").

- = -

⌥- = –

⇧⌥- = —

If you're on Linux (maybe macOS supports this too?) you can open the keyboard settings and turn one of several keys into the Compose/Multi key (I picked CapsLock because I rarely hit it on accident and don't use it). Then you can type all kinds of weird combinations:

https://www.x.org/releases/X11R7.7/doc/libX11/i18n/compose/e...

For example, em dash is Compose+minus+minus+minus, en dash is Compose+minus+minus+period.

It's also useful for foreign glyphs like Compose+a+a for the Nordic å, Compose+s+s for German ß (with Shift it becomes ẞ, which the new German orthography rules officially recognise!), Compose+quote+<vowel> for the various umlauts and Compose+i+period for the dotless ı (with Shift it becomes the dotted İ).

The best way to enter arbitrary Unicode characters on Linux I have found is fcitx's https://fcitx-im.org/Unicode

Just press Ctrl-Alt-Shift-U, type (part of) the name of the character and select from the list of results.

— (em dash), ︱ (presentation form for vertical em dash), ⤐ (rightwards two-headed triple-dash arrow), ﷽ (arabic ligature bismillah ar-rahman ar-raheem) are all easy to enter.

I'm using AutoHotKey on Windows. Not only for this, but for other things, as well.

For example (<^>! means the AltGr key):

  <^>!4::Send „
  <^>!5::Send “
  <^>!2::Send ‚
  <^>!3::Send ‘
  <^>!+6::Send “
  <^>!+7::Send ”
  <^>!+8::Send ‘
  <^>!+9::Send ’
  <^>!-::Send –
  <^>!.::Send …

Also to use Caps Lock as another Control key:

  Capslock::Ctrl

Or make windows stay on top of others, if even they lose focus:

  <^>!t::Winset, Alwaysontop, TOGGLE, A

Fire up vim, use a digraph (^K followed by the two relevant characters -- I believe em dash is -M -- in insert mode), copy & paste.

Nobody's keyboard had an em-dash key (well, maybe some compositor keyboards...). It's well worth the time to figure out how to enter at least the most useful Unicode characters. See, here's an em-dash: —.

Linux users should enable the compose key, it's very useful.

Test it with:

  setxkbmap -option compose:menu

Then press the menu/compose key (next to right control), then C, then =. You get €.

Try compose, 1, 2 for ½.

Compose, ^, 3 for ³.

Compose, A, : for Ä.

It's pretty intuitive for the most useful characters, and easily the fastest way I have of typing the ö, ñ and å in various colleagues' names.

Actually, A: is not valid with the default compose bindings (it is however valid with vim digraphs). In general umlauts or trémas are inserted with the double quote (A").

Worth noting that international layouts (with dead keys) support many of those without the use of compose key (for obvious reasons not your first example – but the € symbol has its own key combination at least where it's commonly used). I admit it might be hard to adjust to caret being a dead key, though.

Dead keys support accents, and a few symbols printed on the keyboard are discoverable, but I find the Compose key is much more intuitive for occasional use.

I don't yet speak the language of my adopted country, so it's better for me to keep []{} etc where I like them in the British layout, and use three keypresses for typing the ø in a (place) name like København.

If I do end up typing lots of Danish, I'll probably map AltGr+A,E,O to Å, Æ, Ø. É is rare, so I'll still use the Compose key for that and German / Swedish names.

I use the default German keyboard layout. Even with dead keys I wouldn't have Nordic characters or the Turkish dotless i and dotted I. I love the Compose key. It's actually making me consider using the US layout because the lack of German glyphs was what was keeping me back.

I use the code behind this web app: http://latex2unicode.herokuapp.com/

It converts latex to unicode where possible. It's pretty impressive how much of Latex can be replaced with Unicode today.

This program translates LaTeX markup to human-readable Unicode when possible.

Here's the default text from that webapp:

Basic math notations: ∵ A͡B + B͡C ≠ A͡C ∴ ∬∜x̅ ξᶿ⁺¹ - ⅜ ≤ Σ ζᵢ ∴ ∃x∀y x ∈ Â

Easily type in hundreds of other symbols and special characters: , ℵ, Œ, ⇊, etc.

Font styles support: 𝔹𝕝𝕒𝕔𝕜 𝔹𝕠𝕒𝕣𝕕 𝔹𝕠𝕝𝕕, 𝔉𝔯𝔞𝔨𝔱𝔲𝔯, 𝐁𝐨𝐥𝐝 𝐅𝐚𝐜𝐞, 𝓒𝓪𝓵𝓵𝓲𝓰𝓻𝓪𝓹𝓱𝓲𝓬, 𝐼𝑡𝑎𝑙𝑖𝑐, 𝙼𝚘𝚗𝚘𝚜𝚙𝚊𝚌𝚎.

Now type in this box and try it yourself. ⌣̈

Careful — some of the Unicode pseudoalphabets won't render on mobile.

No problem on iOS; I see the same thing that I see on my Windows desktop.

If I need a special character, I find a web page or document that has it and use copy/paste.

I have an A4 pinned next to me with all the windows Alt codes. Old-school methods are fastest and I subconsciously learn them by heart over the years.

Nice idea. I don't need them often enough to bother. Do you have a source for the chart?

Yeah. Can't count how many times I've just googled "yen" or "e with accent" because I can't remember the shortcut.

Even then the character pallete built into MacOS is much more convenient for searching, saving, and inputting.

The character palette built into Windows uses too small a font, I find it almost useless. And the size is not adjustable. I've been tempted on more than one occasion to write my own.

Keyboards and typing aids can enter any character if you configure them properly.

not that HN needs more pedantry, but HN’s lightweight markup format is not in any sense a Markdown. I believe that literally the only thing they have in common is that a single set of asterisks yields italics. Bolding, headings, code, lists, quotes, links, etc. don’t transfer from one to the other.