Deprecation of $ in favour of xor

[simonbyrne]

JuliaLang/julia#18977

[nalimilan]

Could you add a test?

[GunnarFarneback]

This doesn't cover ⊻=. Is it at all possible to support that with Compat?

julia> using Compat

julia> x = true
true

julia> x $= true
false

julia> x ⊻= true
ERROR: syntax: unexpected "="

[stevengj]

No, ⊻= isn't parsed as an operator in 0.5. You have to write x = x ⊻ true

[GunnarFarneback]

Ok. That's a bit unfortunate for the specific piece of code I'm working with since ⊻= will look nicer once 0.5 support can be dropped.

In case someone else should run into this, this is the alternative solution I chose for the 0.5 to 0.6 transition (skipping Compat):

if isdefined(:xor)
    macro x(ex)
        arg1 = ex.args[1]
        arg2 = ex.args[2]
        return esc(:($(arg1) = $(arg1) ⊻ $(arg2)))
    end
else
    const ⊻ = $
    macro x(ex)
        return esc(ex)
    end
end

and decorating all use of $= with the @x macro.