Zig Interfaces

Easy solution for all your zig dynamic dispatch needs!

This project is a fork of interface.zig which aims to port the project to zig 0.14.1 as a fetchable library. It changes certain behavior and naming conventions see Example for details.

Features

• Fully decoupled interfaces and implementations
• Control over the storage/ownership of interface objects
• Comptime support (including comptime-only interfaces)
• Optional function support
• Support for manually written vtables

Install

Run the following command to install into a zig project

    > zig fetch --save git+https://github.com/JacobHumphreys/interface.zig.git

Then Add the following to build.zig

    const interface_lib_dep = b.dependency("interface", .{});
    const interface_lib = interface_lib_dep.module("interface");

    const exe = b.addExecutable(.{
        //Find this setting
    });

    //paste this after
    exe.root_module.addImport("interface", interface_lib);

Example

const std = @import("std");
const interface = @import("interface");
const SelfType = interface.SelfType;

const ExampleInterface = struct{
    const Definition = interface.Define(struct {
        print: *const fn (*SelfType, []const u8) void,
    }, .non_owned);

    impl: Definition,

    //Inlining is optional
    pub inline fn Impl(impl_ptr: anytype) ExampleInterface {
        return ExampleInterface{
            .impl = Definition.init(impl_ptr),
        };
    }

    //Inlining is optional
    pub inline fn print(self: ExampleInterface, message: []const u8) void {
        return self.impl.call("print", .{message});
    }
};

const ExampleImpl = struct{
    property: u32,

    pub fn print(self: *ExampleImpl, message: []const u8) void {
        std.debug.print("prop: {}\nmessage: {s}\n", .{self.property, message});
    }
};

pub fn main() !void {
    var exampleStruct = ExampleImpl{
        .property = 1,
    };

    const impl_from_struct: ExampleInterface = ExampleInterface.Impl(&exampleStruct));

    callPrintOnExample(impl_from_struct);
}

fn callPrintOnExample(printer: ExampleInterface) void {
    printer.print("Interfaces!");
}

See example-project directory for full implementation details.

See testing.zig for more examples.