From: Luis Lavena <luislavena@...>
Date: 2010-11-08T21:45:14+09:00
Subject: Re: irb misbehaviour with arrow keys on Windows

On Nov 7, 10:19 pm, Heesob Park <pha...@gmail.com> wrote:
> Hi,
>
> 2010/11/7 Marvin Gülker <sutn...@gmx.net>:
>
>
>
>
>
>
>
> > Hi there,
>
> > It seems that irb has problems with the arrow keys on Windows. Steps to
> > reproduce:
>
> > 1. Start up CMD.
> > 2. Type "irb" and press return
> > 3. Type "abc" and *do not* press return
> > 4. Press the right arrow key
> > 5. Now try typing "defg" - the characters don't show up anymore. If you
> > press return followed by the up arrow key, the whole sequence you typed,
> > including the mysteriously invisible characters, shows up.
>
> > I'm using ruby 1.9.2p0 (2010-08-18) [i386-mingw32] on Windows Vista
> > 32-bit, installed by extracting the 7z archive provided by the
> > RubyInstaller team to C:\Rubies\ruby-1.9.2-p0-i386-mingw32. Of course I
> > added the bin\ subdirectory to my PATH variable.
> > I don't know wheather in matters, but I don't have the RubyInstaller's
> > devkit installed, but a separate MinGW+MSYS installation in C:\MinGW
> > which is up-to-date.
>
> > Anyone experiencing the same problem?
>
> This is a bug of rbreadline.
>
> Here is a patch for rbrealine.rb
> --- rbreadline.rb       2010-11-08 10:10:28.000000000 +0900
> +++ rbreadline.rb.new   2010-11-08 10:10:11.000000000 +0900
> @@ -8435,21 +8435,20 @@
>           count -= 1
>        end
>
> +      str = (flags == MB_FIND_NONZERO) ? string.strip : string
> +
>        case @encoding
>        when 'E'
> -         point += string[point..-1].scan(/./me)[0,count].to_s.length
> +         point += str[point..-1].scan(/./me)[0,count].to_s.length
>        when 'S'
> -         point += string[point..-1].scan(/./ms)[0,count].to_s.length
> +         point += str[point..-1].scan(/./ms)[0,count].to_s.length
>        when 'U'
> -         point += string[point..-1].scan(/./mu)[0,count].to_s.length
> +         point += str[point..-1].scan(/./mu)[0,count].to_s.length
>        when 'X'
> -         point += string[point..-1].force_encoding(@encoding_name)[0,count].byt
> +         point += str[point..-1].force_encoding(@encoding_name)[0,count]bytesi
>        else
>           point += count
>        end
> -      if flags == MB_FIND_NONZERO
> -         point = string.length if point>=string.length
> -      end
>        point
>     end
>

Park, if you believe so, please commit to rb-readline repository and
document why this is happening.

Is hard for me follow this as I'm not able to reproduce the bug and
clearly you know better what is going on down the pipes.

Thank you.
--
Luis Lavena