how to avoid leading white spaces

[rusi]

On Jun 3, 7:25 pm, Steven D'Aprano <steve
+comp.lang.pyt... at pearwood.info> wrote:

> Regarding their syntax, I'd like to point out that even Larry Wall is
> dissatisfied with regex culture in the Perl community:
>
> http://www.perl.com/pub/2002/06/04/apo5.html

This is a very good link.
And it can be a starting point for python to leapfrog over perl.
After all for perl changing the regex syntax/semantics means deep
surgery to the language. For python its just another module.

In particular, there is something that is possible and easy today that
was not conceivable 20 years ago -- using unicode.
Much of the regex problem stems from what LW calls 'poor huffman
coding'
And much of that is thanks to the fact that regexes need different
kinds of grouping but the hegemony of ASCII has forced a
multicharacter rendering for most of those.

A snip from the article:

----------------------------------
Consider these constructs:

    (??{...})
    (?{...})
    (?#...)
    (?:...)
    (?i:...)
    (?=...)
    (?!...)
    (?<=...)
    (?<!...)
    (?>...)
    (?(...)...|...)

These all look quite similar, but some of them do radically different
things. In particular, the (?<...) does not mean the opposite of the (?
>...). The underlying visual problem is the overuse of parentheses, as
in Lisp. Programs are more readable if different things look
different.

----------------------------------
Some parenthesis usage shown here
http://xahlee.blogspot.com/2011/05/use-of-unicode-matching-brackets-as.html