supported backslash escapes

[Skaperen]

in this:

Output:
>>> repr('\n')
"'\\n'"
>>> repr('\b')
"'\\x08'"
>>>

you can used either backslash escape in source code but repr() does not produce both, just newline. is there a way i can reverse codes back their backslash forms for every backslash escape that is supported in Python source code?

[Gribouillis]

is there a way i can reverse codes back their backslash forms for every backslash escape that is supported in Python source code?

You can replace \x08 in the repr by \b and similarly for the other escaped characters.

[Skaperen]

You can replace \x08 in the repr by \b and similarly for the other escaped characters.

i was thinking of making my own conversion but this is a better idea.

[Skaperen]

You can replace \x08 in the repr by \b and similarly for the other escaped characters.

i will need to use raw strings or escape the \ to make .replace() calls.

[Gribouillis]

I would use something like (untested)

mapping = {
    repr('\b'): r'\b',
    repr('\n'): r'\n',
    ...
}

def func(match):
    s = match.group(0)
    return mapping.get(s, s)

result = re.sub(r'\\(?:\\|x[a-f0-9]{2})', func, text)

[Skaperen]

here is what i initially created:

def unctrl(s):
    """Control characters (in str or bytes or bytearray) become backslash equivalents."""
    if isinstance(s,str):
        return repr(s)[1:-1].replace('\\x00','\\0').replace('\\x07','\\a').replace('\\x08','\\b').replace('\\x09','\\t').replace('\\x0a','\\n').replace('\\x0b','\\v').replace('\\x0c','\\f').replace('\\x0d','\\r')
    elif isinstance(s,(bytes,bytearray)):
        return repr(s)[1:-1].replace(b'\\x00',b'\\0'),replace(b'\\x07',b'\\a').replace(b'\\x08',b'\\b').replace(b'\\x09',b'\\t').replace(b'\\x0a',b'\\n').replace(b'\\x0b',b'\\v').replace(b'\\x0c',b'\\f').replace(b'\\x0d',b'\\r')
    else:
        raise TypeError(f'unctrl(): argument needs to be str or bytes or bytearray, not {s!r}')

if i need to just start over, tell me. note that i am supporting bytes because of support for files that can have bytes that are invalid as UTF-8.

[Gribouillis]

if i need to just start over, tell me

What if the repr is "\\\\x07" ? or '\\\\\\x07'

[Skaperen]

What if the repr is "\\\\x07" ? or '\\\\\\x07'

good point to think about. thanks!!

[Skaperen]

I believe you can replace \x08 in the repr by \b and similarly for the other escaped characters.

but it might originally be a couple \ followed by plain text 'x08'. you'd see "\\\\x08". you don't want to replace the last 4 with '\b' pretending that was an original. even if you do "\\\\" -> '\\' first, it would still really be "\\\\x08" -> '\\x08' and then if "\08" -> '\b' is applied, you now have '\\b'. how would that get to the real original? stateful context means something. this depends on how many \ precede it since \ can escape \ instead of only allowing '\x05c'. maybe you might have '\\x05c' some day.