4 ms·
complex c = 4; Would you rather have this line not compile because 4 is not a complex number? Because one _could_ argue that 4 is a complex number, and C++ can
by brianush1 6y ago
complex c = 4;
Would you rather have this line not compile because 4 is not a complex number? Because one _could_ argue that 4 is a complex number, and C++ can represent this with an implicit constructor.
The issue with C++ is that implicit is the default, not that it exists.
- eru 6y agoHaskell solves this reasonably well. If your data type implements the Num typeclass, you can use literals like 4. (A typeclass in Haskell is similar to what they call an interface in Java.) There's no automatic conversion happening at all. It's done via overloading literals at compile time. (You can do the same for strings.)
- srg0 6y agoC++20 introduced concepts, and now it's possible to specify type constraints, like integral, in a way similar to Haskell typeclasses. What it doesn't solve that by default the compiler tries to find an appropriate implicit conversion. Sometimes it's convenient, sometimes it's harder to see what the code actually does.
- eru 6y agoYes, concepts help a bit, but I'm not sure whether they would be necessary here. Yes, the implicit conversion for all values is part of the problem. The Haskell approach only gives you magic for literals.