Message of 24-Apr-83 06:36:09

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Date: Sun 24 Apr 83 06:36:09-PDT
From: Ethan Bradford <CSL.JLH.BRADFORD@SU-SCORE.ARPA>
Subject: Glitch in C-Rub
To: bug-emacs@MIT-AI.ARPA
cc: csd.kronj@SU-SCORE.ARPA, jlh.bradford@Sierra

Strange problems with C-Rub (^R Tab Hacking Rubout): If I insert 10
tabs on a line (which leaves the cursor at the right margin) then any
other text (which wraps around) then move back to the end of the tabs
(left margin of the second screen line) and type C-Rub, a TAB is
deleted without being converted to spaces.  If the amount of extra
text at the end of the line is 6 characters or less, the re-display is
also wrong; it only does one DELCH on the first screen line (i.e.  the
Excl is moved one space left and no characters are moved from the
second to the first screen line).  Now comes the wierd part: if in the
second case I ask for a re-display or move the cursor or ask for help,
then the display and any other tests reveal that a tab has been
deleted; if instead I immediately type another C-Rub or type a C-Rub
after C-@ or C-X . (chosen as tests since they don't affect the
display), two TAB's are gone and there are 13 (not 14) spaces in their
place!

To reiterate, the exact character sequences which will reproduce the
reported bugs are (starting at the beginning of a line):
  C-U 10 TAB A B C D E F G M-B C-RUB
  (Display will be normal, but a whole tab is deleted.)

  C-U 10 TAB A B C D E M-B C-RUB C-L
  (Display was strange before C-L; now a whole tab is deleted and
   display reflects that.)

  C-U 10 TAB A B C D E M-B C-RUB C-RUB
  (Display is normal, but two tabs were deleted and there are 13
   spaces in their place.)

My terminal is a Zenith 19, but I don't think that's significant.

-- Ethan
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