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Comment by WalterBright | Hacker News Reader

D's had that for many years. It's not a secret!

https://dlang.org/phobos/std_algorithm_searching.html#.any

See the buttons below the example code. You can even edit the examples and try variations.

I was curious for exactly how long "many years" was, and it appears it was added sometime between 2016 to 2017. The last archive without it is from 2016, the next archive with it is 2017:

https://web.archive.org/web/20160405080736/https://dlang.org...

Now that's of course just the website feature. Maybe D had executable examples that were tested by the compiler before Go, which would still be very interesting. However, it does appear Go at least did have the in-browser feature as far back as 2015:

https://go.dev/blog/examples

Not that this matters for much other than historical interest: good ideas like this should be copied shamelessly (and obviously it's not a terribly original idea to begin with, just a good implementation of it.)

> Maybe D had executable examples that were tested by the compiler before Go

Sounds like D's ability to specify unit tests in production source code, and have them optionally executed, fits the bill for that.

https://dlang.org/spec/unittest.html

Builtin unit tests were a great leap forward for code verification.

Having unit testing built-in to the programming language and tooling is a huge plus, absolutely. I don't know who originally came up with this, but I swear, it would be worth some recognition :) (And thankfully, whoever did originally come up with this idea, it has been copied a ton by the recent crop of programming language designs.)

The E language supported doctests when I came to it in the 90s: http://erights.org/elang/tools/updoc.html

It's the earliest I'm aware of.

Quite a few D features have made it into other languages:

1. integrated documentation

2. unit tests

3. 1_000_000 literals

4. ranges

5. compile time function execution

6. static if

Unless there is a time machine to have D come up before Smalltalk and Common Lisp/Interlisp-D, it definitely did not do 1, 2 and 3 as influence to other languages.

Those languages have indeed been around decades before D. But somehow those features did not move into the general language community until after D was very successful with them and popularized those features in a modern language.

BTW, the 1_000_000 specifically came from Ada 1983.

The agile movement is what popularised them, driven by key figures in the Smalltalk and Lisp community, pushing them via Java, Ruby and Python.

All of them predating D.

The secret is D's existence.

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