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Comment by Longhanks | Hacker News Reader

Yes, already since C++20. But if you really would have wanted to change your mind, you could’ve found out easily.

Most people don't have time to spend repeatedly checking for features in languages they don't use.

If people don’t have time to keep up with a languages updates (which, in case of C++, is currently _once_ every three years), then they don’t have time to complain about the lack of features, either. This one had the time to complain and just didn’t want to bother typing "c++ string formatting", which would have been fewer keystrokes than the comment complaining.

On DuckDuckGo, the very first result for "c++ string formatting" is the exact thing this person was complaining about.

But then he'd have missed out on your conversational effervescence.

OP asked about “f-strings like python has”, which is different from plain std::format().

Google finds https://stackoverflow.com/questions/62781161/is-it-possible-... which is a portal to horrors with the answer "no"

That about wanting to change mind... it touches a string! Somehow the let-downs must have been too much for me at a certain point in time. That being said, I'm curious to find out right now. Edit... no such thing found as string interpolation in cpp, at least not in my first 4 search hits. I'll crawl back.

String interpolation is currently blocked by:

- template-function parameters (NTTPs with a function parameter syntax rather than a template parameter syntax, tentatively spelled as `void foo(template int constant){}` )

- Scalable reflection, in combination with expansion statements (likely in C++26, spelled `template for (auto& e : array) {}` ) which would allow you to write an arbitrary parser for the template string into real C++ code. Reflection targets C++29.

Syntax2 already supports string interpolation as a special compiler feature.

std::string formatted_str = std::format( "My name is {} and my favorite number is {}", name, num);

That's really nothing like python strings, which for the same string would be

    formatted_str = f"My name is {name} and my favorite number is {num}"

The function call I could forgive, but the the ability to embed arbitrary python expressions into the f-string directly is a huge readability win IMO.

Meanwhile Perl's over here like "we had this in the 90s!" (:

eg:

    perl -e '$x="AAA"; print "lowercase: ${\(  lc($x)  )}\n"'

Of course posix shells gad that even before. How far we can go? What's the first language that had something that resembles string interpolation?

I'm sure someone here can say something about Lisp machines (:

Well, if that's the syntax, I'd rather not have it!

That type of interpolation is something most non-scripting languages don't have anyway, and it took Python several decades to get it, and only has had it in the 5 years or so.

You misunderstand.

C++20 added std::format [1], similar to Python's str.format [2] (~2010).

But OP said f-strings [3] (2016) which is string interpolation, a language-level feature.

C++ does not have string interpolation.

Not massively important, but IMO quite handy for inline code, e.g. SQL parameterization.

[1] https://en.cppreference.com/w/cpp/utility/format/format

[2] https://docs.python.org/3/library/stdtypes.html#str.format

[3] https://docs.python.org/3/reference/lexical_analysis.html#f-...

>Already since C++20

...Or phrased another way, they finally added them in the latest spec (which the majority of C++ devs aren't even using yet)

C++23 was finalized nearly six months ago so it is not correct to call C++20 the “latest spec”.

I should have said the "latest standard", not "spec", if we're being technical. But EVERY bit of official material is very clear about asserting that C++23 is still a preview/in-progress, not a standard. Saying otherwise is, strictly speaking, incorrect.

https://isocpp.org/std/the-standard

https://www.iso.org/standard/79358.html

https://github.com/cplusplus/draft/blob/main/papers/n4951.md

And quite frankly, what matters to devs is what tooling supports the specification without special configuration, and the answer is "basically none". Not a single compiler fully supports it.

https://en.cppreference.com/w/cpp/compiler_support/23

Also, side note, I'd be surprised if more than a third of C++ devs were even using C++20, based on last year's numbers showing only ~25% adoption:

https://www.jetbrains.com/lp/devecosystem-2022/cpp/

fmt has been available for years and it works with ridiculously old compilers. It’s great to have it standardized but it’s not a new capability that C++ didn’t already have.

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