bitwise operators ~ | & |= &=

[gavinking]

When I first designed the language, I realized the need to use & and | to represent union and intersection of types. Thus, at the value level, it made sense to interpret them as the same operations on Sets. Ceylon didn't have bitwise operations at all, because:

• At the time I didn't view it as a language for pushing bits and bytes around.
• We didn't even have a Byte type, nor the Binary abstraction, and, furthermore, Integer did not specify its representation.
• I didn't want to have operator overloading for & and |.
• I robbed ^ for exponentiation, and gave it a higher precedence than |.
• Parsing the bitshift operators >> and << is really much too painful, and I'm always getting confused between >> and >>>.

Since then, we introduced a Byte type, we added well-defined bitwise and bitshifting operations to Integer, and ultimately I've found myself using Sets much less than I expected, and Bytes much more. Oh, and we've already implicitly overloaded some operators to work on Java types.

Therefore, I propose to overload the operators |, &, |=, and &= to apply not only to Sets, but also to Binarys, and introduce a prefix ~ for bitwise complement.

Note:

• I'm not proposing to add ^ (xor), <<, >>, or >>>.
• Overloading these operators introduces an ambiguity, for types that inherit Set & Binary, but I think that problem is pretty easy to resolve.

[gavinking]

I've now got this working for the Java backend, and pushed it to the bitwise branch.

I still need to implement it for the JS backend.

[gavinking]

Alternatively, if you guys really want xor and bitshifting, we could name the bitwise operators (~), (|), (&), (^), (>>),(<<), and (>>>). And that would mean no need for overloading. Just let me know.

[zamfofex]

Isn’t it possible to do the following?

• Do the overloading thingie;
• Deprecate the operators for Set;
• After a while, remove the operators for Set, keeping them only for bitwise operations.

Or do you still think they are useful for sets?

Personally, I don’t mind either way; I have used bytes and needed bitwise operations in the past whereas I have rarely used sets (and never needed to perform intersection/union on them), but I don’t think I’ve needed bitwise operations enough for me to care about operators. It’s not like imma do fancy bitwise shenanigans in Ceylon as one would do in C for example.

So, whether you keep the operators for sets, for bitwise ops, for both, or remove them altogether, I wouldn’t really mind. (Although I don’t really like the idea of operator overloading that much, to be honest.)

Oh and another thing, how would assignment operators look for the parenthesed operators?

[luolong]

While it is rare to use union and intersection on sets, it is by no means so rare that having operator support for these wouldn't be useful.

[gavinking]

This functionality is now complete and available on master.

Unless anyone has any objections, I'm pretty much happy and ready to close this issue.

[gavinking]

Done. I'm going to close, but feel free to post feedback here, if any. I can easily reopen the issue.