Re: RS/RE and paragraphing macros

[G. Branden Robinson]

Hi Alex,

At 2023-02-21T11:09:13+0100, Alex Colomar wrote:
> On 2/21/23 01:29, G. Branden Robinson wrote:
> > .\" Start a relative inset level (by the amount given in the argument).
> > .\" .RS [indent]
> 
> Which reminds us that this was missing in your recent patch, right? :)

That was deliberate; I'm willing to let the in-source comments lag
terminological revisions to documentation a bit.

> > .de1 RS
> > .  nr an-saved-margin\\n[an-inset-level] \\n[an-margin]
> > .  nr an-saved-prevailing-indent\\n[an-inset-level] \
> >       \\n[an-prevailing-indent]
> > .  ie \\n[.$] .nr an-margin +(n;\\$1)
> > .  el         .nr an-margin +\\n[an-prevailing-indent]
> > .  in \\n[an-margin]u
> > .  nr an-prevailing-indent \\n[IN]
> > .  nr an-inset-level +1
> > ..
> > 
> > RS (1) saves the previous margin setting and "prevailing indent" (this
> > term goes all the way back to McIlroy's 1979 man(7)); (2) insets (moves
> > right) the margin by the amount in the argument, or by the
> > aforementioned prevailing indent if there is no argument; (3) sets the
> > formatter's indentation to this new value (not "0"); (4) updates the
> > prevailing indent by the user-configurable standard indentation
> > (register `IN`); and (5) increments the inset level.
> 
> This confuses me again.  All the references to indentation mean the
> inset-amount, right?

No.

"prevailing-indent" refers to the indentation.  The "inset-amount" is
absorbed additively into the "margin".

> What happens to the actual indentation (as in IP)?

It is disregarded, but preserved for possible restoration upon a
subsequent `RE` call.

> Let's try to improve that then.  I'm still not convinced ;)

It would help me if you'd identify specific sentences I've quoted from
the documentation that you feel are misleading or incomplete.

Regards,
Branden

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