default or foo

[Paolo Redælli]

I propose to add a feature to ANY.

infix "or" (another: like Current): like Current

    do

        if another=Void then

            Result:=Current

        else

            Result:=another

        end

    ensure Result/=Void

    end


to allow writing things like

    print("a default answer" or something_that_can_be_void)

instead of

    local temp: STRING

    do

        temp := something_that_can_be_void

        if temp=Void then

            print("a default answer")

        else

            print(temp)

        end

    end


Inspired by the coalescing operators. See 
https://en.wikipedia.org/wiki/Null_coalescing_operator

Initially I thought of proposing to allow to write "foo or default" like 
in many other languages but this would require to add to the language a 
special case to avoid an exception for a Void call.

Using a pattern "default or foo" just avoid this.

I think it will help writing expressive yet concise code. Think of it as 
an Eiffel-style coalescing operator.

An altertive naming would be to use a free operator but I couldn't find 
one that I like.