[Python-Dev] PEP 498: Literal String Interpolation is ready for pronouncement

[Eric V. Smith]

On 9/5/2015 1:14 PM, Gustavo Carneiro wrote:
> Why not allow string concatenation without plus sign only if/when the
> implementation becomes optimised to allow compile time concatenation? 
> This makes it crystal clear whether the concatenation is compile time or
> runtime. If we allow it now, it's hard to tell without looking at the
> CPython source code...

Although you can make it faster than '+', it's not possible for it to be
a compile-time concatenation. The PEP calls out that it's an expression
that's evaluated at runtime.

I think having strings concatenated with adjacent f-strings follows the
principle of least surprise. I also think it won't get used all that
often, just as compile-time string concatenation isn't seen with great
frequency.

Eric.