Object Constraints

This project provides a proof-of-concept prototype for an object constraints system.

Syntax

@constraint((obj: Foo) => { assert(obj.s >= 0) })
@constraint((obj: Foo) => { assert(obj.r >= 0) })
class Foo
{
    r: number;
    s: number;
}

@constraint((obj: Foo2) => { assert(obj.u >= 0) })
@constraint((obj: Foo2) => { assert(obj.t >= 0) })
class Foo2 extends Foo
{
    t: number;
    u: number;
}

class Foo3 extends Foo2
{
    v: number;
}

@constraint((obj: Foo4) => { assert(obj.w >= 0) })
@constraint((obj: Foo4) => { assert(obj.v >= 0) })
class Foo4 extends Foo3
{
    w: number
}

let obj = new Foo4();

obj.r = 6;
obj.s = 5;
obj.t = 4;
obj.u = 3;
obj.v = 2;
obj.w = 1;

Foo4.validate(obj);

class Foo5
{
    @postcondition((result: Foo) => { assert(result.s > result.r) })
    @postcondition((result: Foo) => { Foo.validate(result) })
    @precondition((x: Foo, y: Foo) => { Foo.validate(y) })
    @precondition((x: Foo, y: Foo) => { Foo.validate(x) })
    fun(x: Foo, y: Foo): Foo
    {
        let r = new Foo();
        r.r = 1;
        r.s = 2;
        return r;
    }
}