Re: Zero Width Space

[John Gardner]

>
> What about "input escape"


Copy+pasta from my earlier post
<https://lists.gnu.org/archive/html/groff/2022-06/msg00035.html> to a
concurrent discussion in another thread:

s/input escape/control suppressor/gi
s/input escape/command suppressor/gi

(This discussion appears to have been split between ˜3–4 other threads
<https://lists.gnu.org/archive/html/groff/2022-06/threads.html#00004>, so
I'm unsure which to reply to…)


On Mon, 6 Jun 2022 at 15:55, Ingo Schwarze <schwarze@usta.de> wrote:

> Hi,
>
> DJ Chase wrote on Sun, Jun 05, 2022 at 09:57:45PM +0000:
> > On Sun Jun 5, 2022 at 1:09 PM EDT, Ingo Schwarze wrote:
> >> Richard Morse wrote:
>
> >>> How about "non-breaking escape"
>
> >> That's much too broad since most escape sequences are non-breaking.
>
> >>> or "non-printing escape" (not necessarily in that order of preference)?
>
> >> That's also too broad for my taste; here are a few more escape
> >> sequences that are non-printing and non-breaking unless i'm
> >> missing something: \{ \} \F \f \H \k \M \m \R \S \s \z
> >> The difference between \& and the others is that \& is a no-op
> >> whereas the others all have some side effect.
>
> > What about "input escape",
>
> I wouldn't consider that helpful terminology.
> I would define the term "escape sequence" as "a sequence of
> input characters starting with the escape character, which is the
> backslash by default."  Usually, every escape sequence is intended
> to directly or indirectly affect output, just like any other roff
> input including text lines, requests and macros.  In that sense,
> every escape sequence is both an "input escape" and and "output
> escape": Input and output are merely two complimentary aspects of
> the behaviour of any escape sequence.  Even using \& usually intends
> to influence output, for example suppress end-of-sentence spacing,
> kerning, or ligature building.  So it is hardly more focussed on
> the input side than other escape sequences.
>
> > possibly with a comparing it to the intended
> > purpose of the ASCII escape character?
>
> I dislike that idea, too.  When i consider terminal control codes
> or the use of the escape key in emacs(1) as examples, it seems
> to me that the ASCII escape character compares more readily to
> the roff(7) escape character (by default the backslash) than to
> a complete escape sequence like "\&".  Even if you disregard that
> aspect, the \& escape sequence significantly differs from the
> ASCII escape character in two important aspects: it is often placed
> *after* the thing it is meant to escape rather than before, and
> while the ASCII escape character often gives special meaning to
> ordinary characters, \& does about the opposite: It takes away
> the special meaning that an input character (like '.') intrinsically
> has and turns it into an ordinary character, makes it behave like
> any other character that has no special meaning.
>
> Yours,
>   Ingo
>
>