Re: [PATCH] gnulib-tool.py: Fix configure.ac output.

[Bruno Haible]

Collin Funk wrote:
> > I guess I wasn't very familiar with raw strings when I did this change.
> 
> No worries, it was pretty easy to find and fix. I remember a professor
> in college telling us to always use them for Python regular
> expressions. It seems this is also recommended by the Python people,
> see the '\' character under this page:
> 
> https://docs.python.org/3/library/re.html#regular-expression-syntax

Indeed, this doc contains the explanation for the 'pycodestyle'
warning that I was seeing. With a plain string instead of a raw string,
I get:

$ pycodestyle *.py
...
GLEmiter.py:535:26: W605 invalid escape sequence '\.'
GLEmiter.py:535:35: W605 invalid escape sequence '\.'
...

which indicates that the Python parser would have eaten up the backslash
before the regular expression engine could see it.

Bruno