Proposed alias for union types

Internals & Design
,
84

I created a package at GitHub - mkitti/OrUnions.jl: Julia package to evaluate alternate Union syntax via | and ∨ . To avoid piracy I used ∨ (\vee) rather than |.

julia> 0x5::(UInt8 ∨ Int8)
0x05

julia> f(x::(Int8 ∨ UInt8 ∨ Int)) = x
f (generic function with 1 method)

If you really want to use |, I created a macro called @orunion.

julia> @orunion function foo(::Int8 | UInt8 | Int16) end
foo (generic function with 1 method)

julia> methods(foo)
# 1 method for generic function "foo" from Main:
 [1] foo(::Union{Int16, Int8, UInt8})
     @ REPL[34]:1

julia> @macroexpand @orunion function foo(::Int8 | UInt8 | Int16) end
:(function foo(::Union{Int16, UInt8, Int8})
      #= REPL[36]:1 =#
      #= REPL[36]:1 =#
  end)

julia> @orunion bar(x::Int8 | UInt8, y::Int16 | UInt16, z::(Int8 | UInt8) | Int) = nothing
bar (generic function with 1 method)

julia> methods(bar)
# 1 method for generic function "bar" from Main:
 [1] bar(x::Union{Int8, UInt8}, y::Union{Int16, UInt16}, z::Union{Int64, Int8, UInt8})
     @ REPL[38]:1

julia> @macroexpand @orunion bar(x::Int8 | UInt8, y::Int16 | UInt16, z::(Int8 | UInt8) | Int) = nothing
:(bar(x::Union{UInt8, Int8}, y::Union{UInt16, Int16}, z::Union{Int, Union{UInt8, Int8}}) = begin
          #= REPL[40]:1 =#
          nothing
      end)

julia> methods(@orunion (x::Int8 | UInt8)->5)
# 1 method for anonymous function "#35":
 [1] (::var"#35#36")(x::Union{Int8, UInt8})
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