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

Guido van Rossum guido at python.org
Fri May 10 20:48:51 CEST 2013

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?

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

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