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Comment by Analemma_ | Hacker News Reader

Removing features from a programming language is almost impossible; it breaks backwards compatibility and so is a hard barrier to upgrading from the old version. Note the 12-year-and-counting struggle to adopt Python 3, or the fact that Perl 6 developers gave up completely trying to get people to upgrade from Perl 5 and just rebranded it as a new language instead.

C++ has opted to avoid those struggles by never removing features; you can disagree with that decision but it was done for good reasons.

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I'm speaking strictly technical here, but there have been features that have been removed. Trigraphs (I think), and the register keyword. Moreover, there are objects that are very clearly marked deprecated, like auto_ptr. (Oh, and there is even talk of removing 'volatile' as a keyword.)

The register keyword issue crops up because legacy code included and linked to modern C++ will occasionally have the word "register" affixed to a loop variable. Generally speaking, once you change standards, there is room to drop the old stuff. It's just gradual. Static analyzers do a lot to modernize code now too, so the situation is not as painful as it used to be.

The `volatile` deprecation is more about providing new library features to do the things people (incorrectly) use `volatile` for today. `volatile` will still have legitimate use-cases.

On the other hand, JavaScript very successfully added strict mode that removed features like `eval`. The trick seems to be to ensure that "old code" and "new code" can live side-by-side during a transition period.

Vittorio Romeo has been proposing[0] an "epochs" feature for C++ which would enable modes like "strict." This would let them define things like const-by-default, requiring nulltpr instead of 0, etc. He's facing some resistance by other WG21 members.

[0] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p188...

> the fact that Perl 6 developers gave up completely trying to get people to upgrade from Perl 5 and just rebranded it as a new language instead

This statement does not do justice to the process that led to the renaming of "Perl 6" to "The Raku Programming Language". If you are interested in the process, https://github.com/Raku/problem-solving/issues/81 will give you some of the discussion that happened online.

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