[Python-Dev] Dash

[Serhiy Storchaka]

19.07.13 00:49, Ezio Melotti написав(ла):
> On Thu, Jul 18, 2013 at 7:38 PM, Serhiy Storchaka <storchaka at gmail.com> wrote:
>> What type of dash is preferable in the documentation? The en dash (–) or the
>> em dash (—)?
>>
>
> Both should be used where appropriate [0].

Of course I looked in Wikipedia before asking on this list. And I were 
surprised that en-dash allowed in same places as em-dashes:

"""
Either version may be used to denote a break in a sentence or to set off 
parenthetical statements, although writers are generally cautioned to 
use a single form consistently within their work. In this function, en 
dashes are used with spaces and em dashes are used without them:[1]

[Em dash:] In matters of grave importance, style—not sincerity—is the 
vital thing.

[En dash:] In matters of grave importance, style – not sincerity – is 
the vital thing.
"""

I'm asking only about this case, when the dash is used to denote a break 
in a sentence or to set off parenthetical statements. Currently Python 
documentation uses fourth variants:

1. A single hyphen "-" surrounded with spaces. "In matters of grave 
importance, style - not sincerity - is the vital thing."
I think this case should be converted to one of followed, but to what of 
them?

2. A double hyphen "--" (converted to en-dash) surrounded with spaces. 
"In matters of grave importance, style -- not sincerity -- is the vital 
thing."

3. A triple hyphen "---" (converted to em-dash) surrounded with spaces. 
"In matters of grave importance, style --- not sincerity --- is the 
vital thing."

4. A triple hyphen "---" (converted to em-dash) which isn't surrounded 
with spaces. "In matters of grave importance, style---not sincerity---is 
the vital thing."

>  The em dash is more
> common, however "--" (commonly used to indicate the em dash in e.g.
> emails) gets converted to an en dash by Sphinx [1].  I noticed this a
> while ago, and I started using "---" in the documentation whenever I
> wanted an em dash.

This is common in TeX.