[bug #55154] .tr has undocumented and inconsistennt space-character restrictions

[Dave]

URL:
  <https://savannah.gnu.org/bugs/?55154>

                 Summary: .tr has undocumented and inconsistennt
space-character restrictions
                 Project: GNU troff
            Submitted by: barx
            Submitted on: Mon 03 Dec 2018 06:18:36 AM CST
                Category: None
                Severity: 3 - Normal
              Item Group: None
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None

    _______________________________________________________

Details:

This bug exists in groff 1.22.2 and in a groff built from the latest source in
git.

Consider this groff input.  (The first and third lines end in a space.)

.tr a 
.tr b\~
.tr c\ 
.tr d\|
.tr e\^
.tr f\0

This attempts to translate six alphabetic characters to six different types of
space characters.  What it does instead is accept the first two translations
and reject the last four:

test:3: normal or special character expected (got `\ ')
test:4: normal or special character expected (got a horizontal space)
test:5: normal or special character expected (got a horizontal space)
test:6: normal or special character expected (got a horizontal space)

The documentation says that the space character cannot be translated, but puts
no restrictions on any other character being translated to any type of space
character.

And this is not just undocumented but illogically inconsistent: why should a
printable character be translatable to one type of space and not another?

Even if groff has worked this way since day one, fixing it won't break
backwards compatibility, since such translations were previously disallowed.




    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?55154>

_______________________________________________
  Message sent via Savannah
  https://savannah.gnu.org/