[Bug] No Backspace Capability when Typing a Subreddit about rtv

[michael-lazar]

Works for me in gnome-terminal, what terminal are you using?

Not working in iterm2 for os x

[mishravikas]

Not working on xfce4-terminal 0.6.3

[michael-lazar]

It actually works for me on a fresh install of xfce4-terminal 0.6.3. Try going to preferences -> compatability and check what the backspace key is set to. curses expects control-h (^h). My guess is that iterm2 has a similar issue, but I'm unable to check because I don't have a Mac.

From the curses documentation

    """Editing widget using the interior of a window object.
     Supports the following Emacs-like key bindings:

    Ctrl-A      Go to left edge of window.
    Ctrl-B      Cursor left, wrapping to previous line if appropriate.
    Ctrl-D      Delete character under cursor.
    Ctrl-E      Go to right edge (stripspaces off) or end of line (stripspaces on).
    Ctrl-F      Cursor right, wrapping to next line when appropriate.
    Ctrl-G      Terminate, returning the window contents.
    Ctrl-H      Delete character backward.
    Ctrl-J      Terminate if the window is 1 line, otherwise insert newline.
    Ctrl-K      If line is blank, delete it, otherwise clear to end of line.
    Ctrl-L      Refresh screen.
    Ctrl-N      Cursor down; move down one line.
    Ctrl-O      Insert a blank line at cursor location.
    Ctrl-P      Cursor up; move up one line.

    Move operations do nothing if the cursor is at an edge where the movement
    is not possible.  The following synonyms are supported where possible:

    KEY_LEFT = Ctrl-B, KEY_RIGHT = Ctrl-F, KEY_UP = Ctrl-P, KEY_DOWN = Ctrl-N
    KEY_BACKSPACE = Ctrl-h

[0xr0bert]

I can confirm it doesn't work on iTerm 2

[0xr0bert]

I think iTerm 2 uses ^? as the backspace key (http://www.macfreek.nl/memory/Backspace_and_Delete_key_reversed#iTerm_.28Mac_OS_X_application.29)

[michael-lazar]

So looking through the curses textpad source there are two supported keys for backspace

• curses.ascii.BS which is mapped to 0x08 (^H)
• curses.KEY_BACKSPACE which is mapped to 0x107

It's seems very strange that curses.ascii.DEL which is mapped to 0x7F (^?) is not supported. From the link that you posted that seems to be the standard convention. Sure enough, when I type ctrl-v and press the backspace key, it prints ^? in my terminal.

[michael-lazar]

I still don't understand exactly what's causing this, but I pushed a patch 7738211 to convert 0x7f to a backspace. Please let me know if this fixes the problem for you.

[peterpans01]

I try on Windows but it didn't work,too. (Tested after the patch 7738211). And all the characters after ''Enter Subreddit: /r/" is invisible (maybe it's black!).

[peterpans01]

Sorry, I'm just beginner of curses. After typing the name of subreddit, how can I access it? ENTER key didn't work.

[tobywhughes]

What do you mean by it is invisible? As in, if the text was "/r/python" it shows as "/r/ ython"?

[peterpans01]

No, I mean I can see the cursor change the position but I can't see the text I typed!
Here is the shot after I typed 'python', the small red rectangle is the position of cursors.

[michael-lazar]

Hi @peterpans01, thanks for the heads up.

Did you have to do anything special to get this to work in Windows? According to https://docs.python.org/3.3/howto/curses.html, curses is not included in the Windows version of Python. I'm honestly surprised that this is working for you at all.

My guess is that whatever curses build that you're using has different behavior for some functions, namely this one https://docs.python.org/2/library/curses.html#curses.window.addch. I'll try it out on my Windows box when I get home today.

[Qu4tro]

Just informing that it works fine on xterm.

[peterpans01]

Hi @michael-lazar, it's not so special. I just need to install curses in windows and it's works. 💃 You can try to intall curses here: http://www.lfd.uci.edu/~gohlke/pythonlibs/#curses. I'm still looking for a solution for that.

[tobywhughes]

Is it possible that rtv could install curses automatically if an installation is not found?

[peterpans01]

I confirm that backspace works in Windows 7 and I can fix the errors I show above.

[michael-lazar]

Resolved in #31. Thanks again for looking into this @peterpans01. Once things have settled down a bit, I'll add a section in the README with instructions for installing curses on Windows.