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Subject: Re: [PHP-DEV] [RFC][Under discussion] Arbitrary string interpolation
From: rowan.collins@gmail.com (Rowan Tommins)

On 21/03/2022 10:27, Robert Landers wrote:
 > The downside of a prefix is that it isn't backwards compatible. You 
could use # in a suffix so if you need to write backwards compatible 
code, you can. So maybe:
 >
 > echo "{$x#10.3f}";
 >
 > which can be written like this in backwards compatible code:
 >
 > echo "{$x#10.3f
 > }";


That's a neat trick, although I'm surprised comments are allowed in that 
position given expressions in general aren't.

I think being a syntax error in previous versions is a good thing 
though; falling back to ignoring the formatting specifier could result 
in unexpected behaviour, maybe even leaking data that the formatting was 
intended to hide, and projects which need to support multiple PHP 
versions are more likely to simply use sprintf() to get the same output 
on all versions.

I was also deliberately pairing it with the arbitrary expression syntax 
as one new feature, so that we don't have so many combinations to 
explain to new users ("$x", "{$x}", "{$: $x}", "{$x#10.3f}", "{$: $x 
#10.3f}")

Regards,

-- 
Rowan Tommins
[IMSoP]