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.
I'm surprised that trinary logic has not become a standard part of standard libraries yet. Almost every project I have worked on ends up with some form of a yes/no/maybe abstraction.
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.
This question always reminds me that we often compress far more nuance into binary decisions than reality allows.
In practice most systems end up inventing âsoft booleansâ (flags, states, priorities) to deal with that.
> 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!
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.
I'm surprised that trinary logic has not become a standard part of standard libraries yet. Almost every project I have worked on ends up with some form of a yes/no/maybe abstraction.
With privacy coming back into vogue, itâs useful to distinguish âwe didnât askâ from âthey wouldnât answerâ
For some vector logic the distinction could matter.
I did a govt contract early on and learned that yes/no/unanswered/unasked was a common quad. I see that in disclosures when applying for jobs as well.
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.
For Java developers... you can use Optional<Boolean> to store the elusive four possible booleans.
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.)
>and that it takes up one byte of memory
You can make them smaller using bitfields in C.
The object it's inside will still take up at least one byte.
Amortization.
If one Boolean must be a byte then 8 must be eight bytes. Which is not true. A boolean can be 1/8th of a byte which is a meaningful distinction.
Um, no. Please show me how you can fit 255 possible states in something smaller than a byte by using bitfields.
I was quoting the first paragraph, where it says a single normal bool takes a byte.
This question always reminds me that we often compress far more nuance into binary decisions than reality allows. In practice most systems end up inventing âsoft booleansâ (flags, states, priorities) to deal with that.
> 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!