Formatting Text in C++: The Old and the New Ways

Re:Formatting Text in C++: The Old and the New Ways by ruph123 on Saturday September 16, 2023 @07:37PM (#37539929)

Will C++ ever get the possibility to just print the contents of an object like Rust does (with the automatic debug trait)? I am tired of writing my own print functions for random objects when debugging because the API developers did not bother to override the <<operator. One of those things that are hard to accept when coming back from Rust.

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Re:Formatting Text in C++: The Old and the New Ways by i-use-nixos-btw on Saturday September 16, 2023 @07:52PM (#37540023)

Not until we get reflection. And reflection efforts seem to be at an impasse, so I don’t imagine we will see it for a few years at least.

I will add, though, that I’ve found copilot to be very handy when it comes to generating formatting. Last week I used it while writing fmt::formatter specialisations for a library with 50 structs, some having over 20 members. Writing all of them took about 10 minutes. I dare say the same would hold for operator<< overloads.

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Re:Formatting Text in C++: The Old and the New Ways by ComputerGuru on Sunday September 17, 2023 @01:43AM (#37541880)

Rust does not use reflection for this. Reflection support in rust isn’t actually much better than in C++.

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Re:Formatting Text in C++: The Old and the New Ways by i-use-nixos-btw on Sunday September 17, 2023 @05:08PM (#37549325)

I’m not a rust dev, but looking into how the Debug trait works, it’s basically what we’d need compile time reflection to get in C++.

It generates code that uses the class name and class members. In C++ we have no way of doing that (without hacky macro stuff).

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Re:Formatting Text in C++: The Old and the New Ways by vvanders on Saturday September 16, 2023 @09:36PM (#37540611)

The fact that Rust also has a pretty-print("{:#}")[1] a single character away is also really convenient. When you're working with JSON or debug printing types it's nice to be able to format that without reaching for external tools.

[1] https://doc.rust-lang.org/std/fmt/

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Re:Formatting Text in C++: The Old and the New Ways by shilangyu on Sunday September 17, 2023 @03:03AM (#37542285)

> I am tired of writing my own print functions for random objects when debugging because the API developers did not bother to override the <<operator.

Won't you face the same problem in Rust? If the library developer did not derive the Debug trait, you're out of luck.

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