3 ms·

I'm not sure I'd call Julia a dynamically typed language, each variable can have one and only one (possibly abstract) type which allows the JIT to avoid boxing

• StefanKarpinski 9y ago
  Julia is absolutely dynamically typed [1]. > each variable can have one and only one (possibly abstract) type This is generally untrue except for a rarely used feature allowing declaration of local variables with a certain type (assignment to such variables automatically converts to the declared type). Is this documented incorrectly somewhere? Julia's object model allows a spectrum of array types. At one end, `Vector{Any}` is a Python-like array, and at the other, `Vector{Float64}` is a C-like (or NumPy-like) array with a concrete element type. If the element type is abstract but more constrained than `Any` then you get something in between these extremes. This includes array types like `Vector{Union{Float64,Void}}` and `Vector{Real}`, both of which have abstract element types smaller than `Any`. The former can still store values inline like C arrays, thanks to recent work on efficient representation of unions small values. The latter needs Python-like vector-of-pointers representation because the set of kinds of values it can hold is unbounded since you can add new subtypes of `Real` at any time. [1] https://stackoverflow.com/a/28096079/659248 https://stackoverflow.com/a/28096079/659248
  • Sean1708 9y ago
    > Is this documented incorrectly somewhere? No, I just got myself massively confused at how code_warntype works. Please just disregard everything I said in the above comment.