Gradual typing

Cyan can mix statically-typed and dynamically-typed code, which is called gradual typing. Type Dyn is a virtual type that is supertype of every other prototype.

// no check is needed here
var Dyn d = 0;
var Int n;
// the compiler inserts a runtime
// check: if 'd' does not have type
// Int, there is a runtime type error
n = d;
// runtime type error
var Float f;
f = d;

In the code below, no type is supplied for the parameters of method search:. Theirs types are considered to be Dyn. This code is also here.

package main

object Gradual

    func run {
        Out println: ( self search: [ 3, 9, 7 ], 7 );
        Out println: ( self search: [ "cd", "w", "ab" ], "w" );
        var Dyn d = 0;
        var Int n;
        n = (d + 1)*5;
        n println
    }
    
    func search: array, x -> Int {
        var i = 0;
        while i < array size {
            if array[i] == x {
                return i
            }
            ++i
        }
        return -1
    }

end