ANSI doesn't allow nonprintable characters

[dcoshea]

In 345eb58, in write_ch():

if ch not in string.printable:
    fout = open ('log', 'a')
    fout.write ('Nonprint: ' + str(ord(ch)) + '\n')
    fout.close()
    return

I would like non-printable characters to be accepted, since I am dealing with data streams that include CP437 line drawing characters.

Obviously it's easy to comment out the above lines, but I think it might make more sense for non-printable characters to be accepted, and to leave it up to the caller to decide what to do with any that they find on the virtual "screen" as they see fit. Filtering them out, as is currently done, means that other characters do not appear in their correct locations on the screen, unless this is meant to be a way to filter out line noise, in which case you don't want the cursor to be moved when they are filtered out?

[jquast]

yes, this is wrong. will see.

also for cp437 line-drawing characters, you may be interested in:
https://github.com/jquast/x84/blob/master/x84/encodings/cp437_art.py

and maybe also, https://github.com/tehmaze/piece

[dcoshea]

also for cp437 line-drawing characters, you may be interested in:
https://github.com/jquast/x84/blob/master/x84/encodings/cp437_art.py

I take it that the difference between this encoding and the standard cp437 one is that this one maps the first 32 characters to glyphs (smiley face, etc.) whereas the standard one leaves them with the same ordinal values?

and maybe also, https://github.com/tehmaze/piece

Thanks, but I think that wouldn't work so well for me as it wants me to give it a file, and it parses it all in one hit, whereas I need to feed it data read from a serial interface a byte at a time and process the parsed result.

[jquast]

For a streaming terminal emulator "screen region" access, recommend then also, pyte, see stream.feed() call in example https://github.com/selectel/pyte/blob/master/examples/helloworld.py

[jquast]

oh yes, and you are correct -- "cp437_art" is the control characters are smileys & etc.

[dcoshea]

While I'm working on issue #84 - adding support for Unicode - is it okay if I just get rid of this check for whether the character is printable? If anyone really wanted to exclude non-printable characters, I think (haven't confirmed) that, with my fix for issue #84, they should be able to specify something like codec="ascii", and with the default setting of codec_errors="replace", most non-printable characters should get replaced.

[jquast]

That is correct, technically a utf-8 byte sequence would fail "printable". its up to the decoder to raise UnicodeDecodeError, etc.

[dcoshea]

Filed pull request #96 which includes a fix for this issue.

[jquast]

Closing, pexpect's terminal emulation code remains next release but no longer improved, marked deprecated by #240 Suggest any terminal emulation / screen scraping code efforts moved to more concerted project efforts such as https://github.com/selectel/pyte