I’ve been exploring how holy traits are typically implemented in Julia, often seeing patterns like the following: SomeTrait(x::Type) = B() SomeTrait(::Type{<:T}) = A() somefunc(x::T) where {T} = somefunc(SomeTrait(T), x) somefunc(::A, x) = :a somefunc(::B, x) = :b However, I’ve come across a diff…

In your example, is traitfunc supposed to be somefunc? Also, the T in the definition of LiquidityStyle is not defined. And what is the purpose of LiquidityStyle? It seems that it is not used later on.

Yes, sorry, it’s late. I just wanted to give an example of what I understand as the conventional implementation for Holy traits, so I copied from Holy Traits Pattern (book excerpt) , which seems to be the accepted authority for that. Thanks, I corrected the original post!

Just do what’s best in the specific sitation.

The main difference between “boolean” and Holy traits are that Holy traits operate in the type system whereas boolean traits use values. The definitions of each are roughly equivalent but Holy traits are more extensible and probably more performant (due to leveraging Julia’s dispatch). Using boole…

See also [image] Why traits? General Usage I’ve been trying to teach my students traits, only to realize that there is something I don’t fully understand. Is there any different between these two approaches to dispatch? struct A end struct B end ## Holy trait trait1(::A…

[image] screw_dog: More usefully, since all these operations are operating on types the compiler can generally infer which path will be taken during compilation, avoiding run-time dispatch (ie the if statement in the boolean trait example). In practice, even with value-based traits the compil…

Yep, that’s what I worried about. In general, I prefer the “boolean traits” as they are closer to what’s usually called traits in other languges (like Rust).

I think it is better to distinguish traits that return results in the value space (eg values of the same type, such as true::Bool or false::Bool, an Enum, a Symbol, etc), traits that encode this information in the type space, using designated types such as Base.HasShape{N}, a payload in a Val{…

There are quite a few traits packages these days but BinaryTraits.jl allows you to define something that an object can do (positive) or cannot do (negative). Perhaps you can take a look. [image] GitHub - tk3369/BinaryTraits.jl: Can do or not? It's easy. See... Can do or not? It's eas…

Holy traits vs "boolean traits"

General Usage

gdalle March 22, 2024, 8:31am 6

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Holy traits vs "boolean traits"

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