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Date: Sun, 8 Dec 2013 21:26:39 +1100
Subject: Re: Is It Bug?
From: Chris Angelico <rosuav@gmail.com>
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On Sun, Dec 8, 2013 at 9:01 PM, Chris =E2=80=9CKwpolska=E2=80=9D Warrick
<kwpolska@gmail.com> wrote:
> A raw string cannot end with a backslash.
>
>>>> r'a\a'
> 'a\\a'
>>>> r'a\'
>   File "<stdin>", line 1
>     r'a\'
>         ^
> SyntaxError: EOL while scanning string literal

Incidentally, the solution to this would be to not use the backslash
to escape the quote. That's what introduces the ambiguity. Instead, a
raw literal could do as REXX does and double the quote to escape it.
(Any whitespace and it's still concatenation as normal. I'm not
advocating REXX's handling there.)

>>> r"asdf""qwer"
'asdfqwer'

If we had a new "pure string" that worked thus:
>>> p"asdf""qwer"
'asdf"qwer'

>>> p"\b""\d+""\b"
'\\b"\\d+"\\b'

which would be a regex matching quoted strings of digits. The only
potential ambiguity would be in that closing the quote and opening
another would normally revert to a regular string literal, where by
this model it's still a pure string. Editor lexers would have to
understand that.

ChrisA