I would like to make a plea on behalf of all present and future bit-twiddlers who also love the power of Julia. Would a mathematician be happy if they were told that they had to lose one of their most frequently used operators? Masking operations are so prevalent, foo &= ~0x00ff for example, or so…

A good way to do this is to define !x = Base.:!(x) !(x::Integer) = (x == 0) in your code. Then there’s not even any piracy.

I guess I’m missing something, how is that definition different from: [image] ScottPJones: Base.:!(val::Integer) = iszero(val) (waiting to learn from the Jedi (oops) Julia Master!) Edit: maybe I get it now, it’s overwriting ! in my package, not extending it, right?

Yes, it’s creating a new ! inside your module that defaults to Base.! behavior for everything but Integers. This way everybody else who uses ! will continue to get the standard behavior (unless they import ! from your module).

The one difficulty is I’d like to make that definition easily available by just using a module, and I don’t see how to do that without extending Base.:!

You would have to say using Foo: !.

I thought that would give a conflict (you know, use must use Base.xxx and Foo.xxx)

Folks - let me know what you feel about my proposal, consolidated from other’s ideas here and on GitHub, and join in the Tomatina (a festival in Spain of throwing tomatos) :grinning:. [image] A Modest Proposal (for !, &, | and ~) Internals & Design Here is my combination …

!(val::Integer) = (val == 0) Please don’t do this. I love that values non-booleans don’t have magic comparison properties like in Python, it’s just too many special cases to remember. Also it would be weird if if !a end worked for a variable where if a end errors.

If ! is used for both logical and bitwise not, couldn’t foo &= ~0x00ff become foo &= !0x00ff which is equally concise?

[image] ggggggggg: it’s just too many special cases to remember. Also it would be weird if if !a end worked for a variable where if a end errors. Special cases? I actually think of it as being a very generic rule, no special cases at all. ! returns a boolean based on the type of the value. …

A Plea for Bit-Twiddlers! (please keep ! as logical negation, separate from bitwise negation!)

Internals & Design

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A Modest Proposal (for !, &, \| and ~) Internals & Design	10	1775	January 13, 2018
Supporting syntax `x not in y` as alias for `!(x in y)` Internals & Design	48	2283	February 23, 2024
What's the difference between the tilde ~ and exclamation ! operators? New to Julia	12	4866	April 25, 2022
On the arbitrariness of truth(iness) Internals & Design	49	6007	March 25, 2023
"and", "or", bitwise or shortcircuit, what we get searching docs New to Julia	60	9393	September 11, 2020

A Plea for Bit-Twiddlers! (please keep ! as logical negation, separate from bitwise negation!)

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