ncurses getch & unicode (was: decoding keyboard input when using curses)

Iñigo Serna inigoserna at gmail.com
Thu Aug 20 18:12:07 EDT 2009


Hi again,

2009/8/20 Iñigo Serna <inigoserna at gmail.com>
>
> I have the same problem mentioned in http://groups.google.com/group/comp.lang.python/browse_thread/thread/c70c80cd9bc7bac6?pli=1 some months ago.
>
> Python 2.6 program which uses ncurses module in a terminal configured to use UTF-8 encoding.
>
> When trying to get input from keyboard, a non-ascii character (like ç) is returned as 2 integers < 255, needing 2 calls to getch method to get both.
> These two integers \xc3 \xa7 forms the utf-8 encoded representation of ç character.
>
> ncurses get_wch documentation states the function should return an unique integer > 255 with the ordinal representation of that unicode char encoded in UTF-8, \xc3a7.

Answering myself, I've copied at the bottom of this email a working
solution, but the question still remains: why win.getch() doesn't
return the correct value?

Kind regards,
Iñigo Serna


######################################################################
# test.py
import curses

import locale
locale.setlocale(locale.LC_ALL, '')
print locale.getpreferredencoding()


def get_char(win):
    def get_check_next_byte():
        c = win.getch()
        if 128 <= c <= 191:
            return c
        else:
            raise UnicodeError

    bytes = []
    c = win.getch()
    if c <= 127:
        # 1 bytes
        bytes.append(c)
    elif 194 <= c <= 223:
        # 2 bytes
        bytes.append(c)
        bytes.append(get_check_next_byte())
    elif 224 <= c <= 239:
        # 3 bytes
        bytes.append(c)
        bytes.append(get_check_next_byte())
        bytes.append(get_check_next_byte())
    elif 240 <= c <= 244:
        # 4 bytes
        bytes.append(c)
        bytes.append(get_check_next_byte())
        bytes.append(get_check_next_byte())
        bytes.append(get_check_next_byte())
    buf = ''.join([chr(b) for b in bytes])
    buf = buf.decode('utf-8')
    return buf

def getcodes(win):
    codes = []
    while True:
        try:
            ch = get_char(win)
        except KeyboardInterrupt:
            return codes
        codes.append(ch)

lst = curses.wrapper(getcodes)
print lst
for c in lst:
    print c.encode('utf-8'),
print
######################################################################


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