[Octave-bug-tracker] [bug #49348] Treat multi-byte characters as one character for char array

[Markus Mützel]

URL:
  <http://savannah.gnu.org/bugs/?49348>

                 Summary: Treat multi-byte characters as one character for
char array
                 Project: GNU Octave
            Submitted by: mmuetzel
            Submitted on: Sat 15 Oct 2016 07:30:58 AM GMT
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Matlab Compatibility
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

In Octave, one char seems to be one byte long always. This leads to the
following issues when reversing or indexing into a character array with
multi-byte characters:

t='abcäöü'
t(end:-1:1)
size(t)
t(4:6)


In Octave:

>> t='abc\303\244\303\266\303\274'
t = abcäöü
>> t(end:-1:1)
ans = �öä�cba
>> size(t)
ans =
   1   9
>> t(4:6)
ans = ä�


In Matlab:

>> t='abcäöü'
t =
abcäöü
>> t(end:-1:1)
ans =
üöäcba
>> size(t)
ans =
     1     6
>> t(4:6)
ans =
äöü



I also noticed that char() doesn't support values >255 and messes up Unicode
characters >127:
In Octave:

>> char (269)
warning: range error for conversion to character value
ans =
>> char(228)
ans = �


In Matlab:

>> char(269)
ans =
č
>> char(228)
ans =
ä


Is this a design choice in Octave? Would it be possible that Octave's char
class treated Unicode characters as such no matter how many bytes they use in
any encoding (UTF-8 seems to be a good choice)?




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