- True | False | FileNotFound was a meme about 2 decades ago, and even that was a reference to MSDOS from another 2 decades earlier. I guess things never change, only the language.
Even now, I still find myself using true/false/null on occasions, but I'm usually smart enough to replace it with an enum at that point. The only time I don't is when it's an optional parameter to a function to override some default/existing value, at which point it then makes sense to keep it as an optional bool.
- "How many options fit into a boolean?"
Five or two, according* to Microsoft.
> MsoTrioState is "a tri-state Boolean value". it has five possible values. only two of them are supported.
*) https://learn.microsoft.com/en-au/dotnet/api/microsoft.offic...
Sourced from here
https://fedi.lynnesbian.space/@lynnesbian/115969259564305759
- It's not clear from the article, but "niche optimization" does not mean "optimization that is only useful in a very specific circumstance".
It is a specific optimization based on the idea of storing one type inside of another type by finding a "niche" of unused bit pattern(s) inside the second type.
It has far more useful application than a tower of Option 254 deep.
- Neat. Even knowing about niche optimization I would have guessed that you could fit 7 Options - one bit for each. But the developers were smart enough to take advantage of the fact that you can't have a Some nested below a None, so you only need to represent how many Somes there are before you reach None (or the data), allowing 254 possibilities.
- The scoop: a boolean can't be smaller than a byte. Full 254 level of nested Option<bool> fit into it. (C++ needs much more for even a single level.)
- For Java developers... you can use Optional<Boolean> to store the elusive four possible booleans.
- The deeper you go into memory layout, the more you realize that even "simple" types aren't that simple.
by johnthescott
0 subcomment
- a two bit, boolish data type used for simple replies from a network: true, false, null and waiting. called a "rummy".
by RobotToaster
3 subcomments
- >and that it takes up one byte of memory
You can make them smaller using bitfields in C.
by mock-possum
0 subcomment
- > looking at Rust … it turns out that `Option<bool>` takes up exactly one byte of memory, the same as bool! The same is true for `Option<Option<bool>>`, all the way up to 254 nested options.
Ah how many of those options fit into that boolean. Word games!
- [dead]
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