Polymorphic copy: Difference between revisions

=={{header|Phix}}==

The object type is the ultimate polymorph - there is <i>nothing</i> that you can store anywhere else that you cannot store in an object.

For this demonstration (not that this really proves much), our types T and S (overkill really) are just going to contain a string name and a method (routine_id).

<lang Phix>enum NAME, METHOD

procedure me_t()

puts(1,"I is a T\n")

end procedure

constant r_t = routine_id("me_t")

procedure me_s()

puts(1,"I is an S\n")

end procedure

constant r_s = routine_id("me_s")

type T(object o)

-- as o[METHOD] can be overidden, don't verify it!

return sequence(o) and length(o)=2 and string(o[NAME]) and integer(o[METHOD])

end type

type S(T t)

return t[METHOD] = r_s

end type

S this = {"S",r_s}

T that = {"T",r_t}

call_proc(that[METHOD],{})

that = this

call_proc(that[METHOD],{})</lang>

{{out}}

<pre>

I is a T

I is an S

</pre>