Re: Re: [RFC] Better string interpolation

On Sun, Aug 16, 2020, 20:45 Ilija Tovilo <tovilo.ilija@gmail.com> wrote: > Hi internals > > > I've been thinking about ways to improve string interpolation. > > Absolutely overwhelmed by the feedback (:P) I've decided to create a small > POC: > > > https://github.com/php/php-src/compare/master...iluuu1994:string-interpolation > > The POC uses the following syntax: > echo "Static method call: #{Foo::bar()}"; > > Two questions arose: > > 1. String prefix > > To mitigate the BC break we could require strings that use the new > interpolation to be prefixed. > > // Continues behaving the same > echo "#{Foo::bar()}"; > // Actually makes use of the new interpolation > echo $"#{Foo::bar()}"; > > The main downside is that we have yet another type of string: Simple > quotes with no interpolation, double quotes with *some* interpolation > and fully interpolated strings ($""), each one with their heredoc > counterpart. It's unfortunate but we might prefer this approach to > mitigate the BC break. > > Let me know if you prefer a prefix or no prefix. If the answers are > inconclusive this might become a secondary vote in the RFC. > > 2. Escaping > > It's not quite obvious how escaping should behave. > > $foo = 'foo'; > echo "\#{$foo}"; > > // Could print > //> 1. #foo > // or > //> 2. #{$foo}" > > We could 1. make the backslash escape just the hash and interpret > {$foo} as usual, or 2. make it escape both. > > * Option 1 is more consistent with the rest of the language, backslash > normally just escapes the next character > * Option 1 requires two backslashes when result 2 is desired ("\#{\$foo}") > * Option 2 makes it impossible to achieve result 1 with just braces > and would have to be written as "\##{$foo}" > > Let me know which option makes more sense to you. > > Ilija > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: https://www.php.net/unsub.php Hi Ilija, I think this could work and thank you very much for the effort into clarifying the current interpolation situation. Using a prefix for strings that have a saner interpretation reminds me of f-strings in python 3. I would suppose you know about it already but I'll leave a link here anyway: https://www.python.org/dev/peps/pep-0498/ Using $ for the prefix might not be the best option as it would look like this: echo $"next is {$i + 1}"; Maybe f can be used similar with how it is in python but I didn't gave too much thought into it. I'm a casual python user so I need to understand more the history how they got to it. Replying from my phone, sorry if my answer is too short, incomplete and with possible spelling mistakes. Regards, Alex