[Python-ideas] Implicit string literal concatenation considered harmful?

[Nick Coghlan]

On 11 May 2013 04:50, "Guido van Rossum" <guido at python.org> wrote:
>
> I just spent a few minutes staring at a bug caused by a missing comma
> -- I got a mysterious argument count error because instead of foo('a',
> 'b') I had written foo('a' 'b').
>
> This is a fairly common mistake, and IIRC at Google we even had a lint
> rule against this (there was also a Python dialect used for some
> specific purpose where this was explicitly forbidden).
>
> Now, with modern compiler technology, we can (and in fact do) evaluate
> compile-time string literal concatenation with the '+' operator, so
> there's really no reason to support 'a' 'b' any more. (The reason was
> always rather flimsy; I copied it from C but the reason why it's
> needed there doesn't really apply to Python, as it is mostly useful
> inside macros.)
>
> Would it be reasonable to start deprecating this and eventually remove
> it from the language?

I could live with it if we get "dedent()" as a string method. I'd be even
happier if constant folding was extended to platform independent method
calls on literals, but I don't believe there's a sane way to maintain the
"platform independent" constraint.

OTOH, it's almost on the scale of "remove string mod formatting". Shipping
at least a basic linting tool in the stdlib would probably be almost as
effective and substantially less disruptive. lib2to3 should provide some
decent infrastructure for that.

Cheers,
Nick.

>
> --
> --Guido van Rossum (python.org/~guido)
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