[haskeline] #84: Vi mode noticeably not backward compatible with readline

[haskeline]

#84: Vi mode noticeably not backward compatible with readline
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Reporter:  jdanbrown  |        Owner:       
    Type:  defect     |       Status:  new  
Priority:  major      |    Milestone:  0.6.2
 Version:  0.6        |   Resolution:       
Keywords:             |  
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Old description:

> Thank you for implementing vi line editing—but–please—also finish the
> implementation!
>
> libreadline has an extensive set of vi commands that most replacement
> libraries fail to match. Here are just a few command-mode keys that I
> notice don't work:
>
>   j - previous line in history[[BR]]
>   k - next line in history[[BR]]
>   e - end of word[[BR]]
>   E - end of bigword[[BR]]
>   f - find character[[BR]]
>   F - find character (backward)[[BR]]
>   t - find character-1[[BR]]
>   T - find character-1 (backward)[[BR]]
>   D - delete rest of line[[BR]]
>   C - change rest of line (delete, then enter insert mode)[[BR]]
>   !^ - go to first non-whitespace character in line[[BR]]
>   p - paste (pos+1)[[BR]]
>   P - paste[[BR]]
>   !^D - enter, when line is not empty[[BR]]
>   % - jump to matching brace: () {} [][[BR]]
>   . - repeat previous command
>
> Additionally, using up/down in command mode puts the cursor at the end of
> the line, whereas readline puts it at the beginning of the line. I'm not
> sure whether one is more convenient or correct, but UI consistency is
> more important here and every other program I encounter uses libreadline.
>
> Note: I'm not sure if v0.6 is correct—this is whichever version ships
> with ghc-6.10.3.

New description:

 Thank you for implementing vi line editing—but please also finish the
 implementation!

 1. libreadline has an extensive set of vi commands that most replacement
 libraries fail to match. Here are just a few command-mode keys that I
 notice don't work:

   j - previous line in history[[BR]]
   k - next line in history[[BR]]
   e - end of word[[BR]]
   E - end of bigword[[BR]]
   f - find character[[BR]]
   F - find character (backward)[[BR]]
   t - find character-1[[BR]]
   T - find character-1 (backward)[[BR]]
   D - delete rest of line[[BR]]
   C - change rest of line (delete, then enter insert mode)[[BR]]
   !^ - go to first non-whitespace character in line[[BR]]
   p - paste (pos+1)[[BR]]
   P - paste[[BR]]
   !^D - enter, when line is not empty[[BR]]
   % - jump to matching brace: () {} [][[BR]]
   . - repeat previous command

 2. Using up/down in command mode puts the cursor at the end of the line,
 whereas readline puts it at the beginning of the line. I'm not sure
 whether one is more convenient or correct, but UI consistency is more
 important here and every other program I encounter uses libreadline.

 3. Both vim and libreadline handle 'cw' specially: instead of deleting the
 sequence of text moved through by the 'w' movement command—the rest of the
 word and any trailing whitespace—it only deletes the rest of the word. So
 'cw'/'ce' and 'cW'/'cE' are synonymous even though 'dw'/'de' and 'dW'/'dE'
 aren't.

 Note: I'm not sure if v0.6 is correct—this is whichever version ships with
 ghc-6.10.3.

Comment (by jdanbrown):

 Added item about 'cw'. (Also removed some accidental dashes in the first
 sentence.)

-- 
Ticket URL: <http://trac.haskell.org/haskeline/ticket/84#comment:7>
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