[bug #58746] [PATCH] doc/groff.texi: Mention that .ds with only one argument defines an empty string

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From	Dave <INVALID.NOREPLY@gnu.org>
Newsgroups	gnu.groff.bug
Subject	[bug #58746] [PATCH] doc/groff.texi: Mention that .ds with only one argument defines an empty string
Date	Sat, 11 Jul 2020 06:26:11 -0400 (EDT)
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URL:
  <https://savannah.gnu.org/bugs/?58746>

                 Summary: [PATCH] doc/groff.texi: Mention that .ds with only
one argument defines an empty string
                 Project: GNU troff
            Submitted by: barx
            Submitted on: Sat 11 Jul 2020 05:26:08 AM CDT
                Category: Core
                Severity: 3 - Normal
              Item Group: Documentation
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

    _______________________________________________________

Details:

This is easy to figure out, but the manual may as well spell it out.

As a real-world use case, I recently had need to build up a roff string inside
a loop, each iteration appending to the string, a la:

.while CONDITION .ds mystring \\*[mystring] and then some

To avoid a warning, I had to initialize "mystring" before the loop.  I first
looked in the manual to find out how to define an empty string; finding no
answer there, I tried the obvious thing, and it worked.

"The obvious thing" having such a spotty track record in *roff syntax in
general, it's probably worth documenting that this one actually does do what
you would hope.  Suggested patch attached.



    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Sat 11 Jul 2020 05:26:08 AM CDT  Name: empty_string.patch  Size: 1KiB  
By: barx
doc/groff.texi: add one sentence, improve nearby punctuation
<http://savannah.gnu.org/bugs/download.php?file_id=49462>

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[bug #58746] [PATCH] doc/groff.texi: Mention that .ds with only one argument defines an empty string Dave <INVALID.NOREPLY@gnu.org> - 2020-07-11 06:26 -0400

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