Contract.zig

Simple comptime type validation for contract-based programming using anytype in zig.

How to install

Just add contract to your build.zig.zon:

zig fetch --save git+https://github.com/felipeasimos/contract.zig.git

and add the import to your modules in build.zig:

const contract = b.dependency("contract", .{
    .target = target,
    .optimize = optimize,
});
lib.addImport("contract", contract.module("contract"));

How to use

The folder tests/ should be pretty explanatory, but basically it checks at compile time if an implementation type has all the functions of an interface type:

const Shape = struct {
    fn area() f64 {
        return 0;
    }
};

const Square = struct {
    side: f64 = 2.0,
    fn area() f64 {
        return 1;
    }
};

const ExampleConsumer = struct {
    fn func(impl: anytype) void {
        comptime contract.validate(@TypeOf(impl), Shape);
    }
};
ExampleConsumer.func(Square{});

If the area function in Square is removed, it will result in a compile error.