'return new'

General Usage
1

I saw code like

return  new{T}(a, b)

as the last the line of some constructor function of a struct.

I am wondering what is the purpose of ‘new’ here? Typically, we see

return (a,b)
2

In inner constructors (ie constructors within the struct block) you can’t call a constructor by name since it hasn’t been defined yet, so we use the new keyword.

That is, new{T}(a, b) should be in a context like:

struct Foo{T} where T
    a::T
    b::T
    function Foo(a, b)
        # do some checks on a, b
        return new{T}(a, b)
    end
end

Here we use new to do the actual allocation/construction of the type.

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