On Tuesday, April 29, 2014 4:38:59 PM UTC+1, John Myles White wrote: > > On Apr 29, 2014, at 8:28 AM, Oliver Woodford > <oliver....@gmail.com<javascript:>> > wrote: > > > Are you saying that f{T<:Real}(a::Array{T}) covers both homogeneous and > heterogeneous arrays, whereas f(a::Array{Real}) only covers heterogeneous > arrays? If that's the case it strikes me as just as confusing. > >> > This is indeed how parametric types work in Julia. > > Array{T} is a family of types, one for each value of T. Defining > f{T}(a::Array{T}) allows you to generically define an infinite number of > functions -- you get a unique function for each value of T. >
Yes, understood. > > In contrast, Array{Real} is a single type -- specifically, the type > generated by the parametric type Array{T} when its parameter T = Real. > There is no variable T, so f(a::Array{Real}) defines exactly one function > -- and that function accepts exactly one type of input. > Yes, understood. > > Array{Any} is also a single type. > > -- John > > However, you haven't addressed the point I make in my post. I will post it again, stated more clearly.