typ 🖨️

A small Zig ⚡ module, as a convenience for me when writing WebAssembly plugins for Typst

Note

Initially based on the hello.zig example in wasm-minimal-protocol

Requirements

You will want to have a fairly recent Zig as well as the Typst CLI

Important

I had to rustup default 1.79.0 when compiling the latest typst as there were some breaking change in 1.80.0

Tip

Some of the software that I have installed for a pretty nice Typst workflow in Neovim:

• https://github.com/nvarner/typst-lsp
• https://github.com/kaarmu/typst.vim
• https://github.com/chomosuke/typst-preview.nvim

Usage

Use zig fetch to add a .typ to the .dependencies in your build.zig.zon

zig fetch --save https://github.com/peterhellberg/typ/archive/refs/tags/v0.1.0.tar.gz

Note

You should now be able to update your build.zig as described below.

build.zig

const std = @import("std");

pub fn build(b: *std.Build) void {
    const target = b.resolveTargetQuery(.{
        .cpu_arch = .wasm32,
        .os_tag = .freestanding,
    });

    const hello = b.addExecutable(.{
        .name = "hello",
        .root_module = b.createModule(.{
            .root_source_file = b.path("hello.zig"),
            .strip = true,
            .target = target,
            .optimize = .ReleaseSmall,
        }),
    });

    const typ = b.dependency("typ", .{}).module("typ");

    hello.root_module.addImport("typ", typ);
    hello.entry = .disabled;
    hello.rdynamic = true;

    b.installArtifact(hello);
}

hello.zig

const typ = @import("typ");

export fn hello() i32 {
    const msg = "*Hello* from `hello.wasm` written in Zig!";

    return typ.str(msg);
}

export fn echo(len: usize) i32 {
    var res = typ.alloc(u8, len * 2) catch return 1;
    defer typ.free(res);

    typ.write(res.ptr);

    for (0..len) |i| {
        res[i + len] = res[i];
    }

    return typ.ok(res);
}

hello.typ

#set page(width: 10cm, height: 10cm)
#set text(font: "Inter")

== A WebAssembly plugin for Typst

#line(length: 100%)

#emph[Typst is capable of interfacing with plugins compiled to WebAssembly.]

#line(length: 100%)

#let p = plugin("zig-out/bin/hello.wasm")

#eval(str(p.hello()), mode: "markup")

#eval(str(p.echo(bytes("1+2"))), mode: "code")

Expected output