Setup Lua module for exporting Rust functions to Lua

.commitlintrc.yml

@@ -51,6 +51,7 @@ rules:
     - pdf
     - readme
     - release
+    - rusile
     - settings
     - shapers
     - tooling

Cargo.toml

@@ -1,20 +1,36 @@
-[package]
-name = "sile"
+[workspace]
+resolver = "2"
+members = [
+  ".",
+  "rusile",
+]
+
+[workspace.package]
 version = "0.15.4"
 edition = "2021"
 rust-version = "1.71.0"
-description = "Simon’s Improved Layout Engine"
 authors = [
   "Simon Cozens",
   "Caleb Maclennan <[email protected]>",
   "Olivier Nicole",
   "Didier Willis"
 ]
-readme = "README.md"
 homepage = "https://sile-typesetter.org"
 repository = "https://github.com/sile-typesetter/sile"
 license = "MIT"
+
+[package]
+name = "sile"
+description = "Simon’s Improved Layout Engine"
+readme = "README.md"
 build = "build-aux/build.rs"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+homepage.workspace = true
+repository.workspace = true
+license.workspace = true
 
 [[bin]]
 name = "sile"

Makefile.am

@@ -54,17 +54,23 @@ endif
 $(MANUAL): $(FIGURES)
 
 BUILT_LUA_SOURCES = core/features.lua core/pathsetup.lua core/version.lua
+RUSILE_SOURCES = rusile/Cargo.toml rusile/src/lib.rs
 
 bin_PROGRAMS = sile
 bin_SCRIPTS = sile-lua
 nodist_man_MANS =
 dist_man_MANS = sile-lua.1
 sile_SOURCES = src/bin/sile.rs src/lib.rs src/cli.rs
 EXTRA_sile_SOURCES =
-if !EMBEDDED_RESOURCES
+if EMBEDDED_RESOURCES
+noinst_LIBRARIES = librusile.a
+librusile_a_SOURCES = $(RUSILE_SOURCES)
+else !EMBEDDED_RESOURCES
 nobase_dist_pkgdata_DATA = $(SILEDATA) $(LUALIBRARIES)
 nobase_nodist_pkgdata_DATA = $(BUILT_LUA_SOURCES) $(LUAMODULES)
-endif
+pkglib_LIBRARIES = rusile.so
+rusile_so_SOURCES = $(RUSILE_SOURCES)
+endif !EMBEDDED_RESOURCES
 dist_doc_DATA = README.md CHANGELOG.md
 dist_pdf_DATA = $(_MANUAL)
 dist_license_DATA = LICENSE.md
@@ -120,6 +126,7 @@ $(CARGO_BIN): justenough/.libs/justenoughicu.a
 $(CARGO_BIN): justenough/.libs/justenoughlibtexpdf.a
 $(CARGO_BIN): justenough/.libs/svg.a
 $(CARGO_BIN): libtexpdf/.libs/libtexpdf.a
+$(CARGO_BIN): librusile.a librusile.so
 
 src/embed-includes.rs: Makefile-distfiles
 	{
@@ -144,6 +151,7 @@ else
 MLUAVER = lua$(LUA_SHORT_VERSION)
 endif
 CARGO_FEATURE_ARGS = --features $(MLUAVER)
+RUSILE_FEATURE_ARG = --features $(MLUAVER)
 
 if !SYSTEM_LUA_SOURCES
 CARGO_FEATURE_ARGS += --features vendored
@@ -157,6 +165,18 @@ if FONT_VARIATIONS
 CARGO_FEATURE_ARGS += --features variations
 endif
 
+rusile.so:
+	$(CARGO_ENV) $(CARGO) build $(CARGO_VERBOSE) $(RUSILE_FEATURE_ARG) $(CARGO_RELEASE_ARGS) -p rusile
+	$(INSTALL) @builddir@/target/@RUST_TARGET_SUBDIR@/lib$@ $@
+
+librusile.a:
+	$(CARGO_ENV) $(CARGO) build $(CARGO_VERBOSE) $(RUSILE_FEATURE_ARG) $(CARGO_RELEASE_ARGS) -p rusile
+	$(INSTALL) @builddir@/target/@RUST_TARGET_SUBDIR@/$@ $@
+
+librusile.so:
+	$(CARGO_ENV) $(CARGO) build $(CARGO_VERBOSE) $(RUSILE_FEATURE_ARG) $(CARGO_RELEASE_ARGS) -p rusile
+	$(INSTALL) @builddir@/target/@RUST_TARGET_SUBDIR@/$@ $@
+
 DEPDIR := .deps
 LOCALFONTS := FONTCONFIG_FILE=$(PWD)/fontconfig.conf
 LOCALPATHS := SILE_PATH="$(PWD);libtexpdf/.libs;justenough/.libs"

build-aux/build.rs

@@ -36,6 +36,8 @@ fn main() {
     generate_shell_completions();
     #[cfg(feature = "static")]
     {
+        println!("cargo:rustc-link-arg=-lrusile");
+
         let dir = env::var("CARGO_MANIFEST_DIR").unwrap();
         println!(
             "cargo:rustc-link-search=native={}",

build-aux/pkg.nix

@@ -117,6 +117,9 @@ in stdenv.mkDerivation (finalAttrs: {
     # `pdfinfo`, by using `false` we make sure that if it is expected during
     # build time we would fail to build since we only provide it at test time.
     "PDFINFO=false"
+    # We're using Cargo to build a shared library skipping some libtool bits
+    # and Nix mistakenly assumes are relevant and thinks it needs to cleanup.
+    "RANLIB=:"
     #"--with-manual" In Nixpkgs we add this flag, here its not important enough
   ] ++ lib.optionals (!lua.pkgs.isLuaJIT) [
     "--without-luajit"

core/sile.lua

@@ -16,6 +16,12 @@ SILE = {}
 --- Fields
 -- @section fields
 
+--- Load the C module that provides any and all SILE features implemented in Rust. The exports in this module are meant
+--- to be moved to approprate places in the Lua API as we load other things and assemble the public facing interface.
+--- This location is considered internal and accessing them directly from here is not supported.
+-- @table SILE.rusile
+SILE._rusile = require("rusile")
+
 --- Machine friendly short-form version.
 -- Semver, prefixed with "v", possible postfixed with ".r" followed by VCS version information.
 -- @string version

rusile/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "rusile"
+description = "Rusty components for the SILE typesetter"
+readme = "README.md"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+authors.workspace = true
+homepage.workspace = true
+repository.workspace = true
+license.workspace = true
+
+[lib]
+crate_type = ["rlib", "cdylib", "staticlib"]
+
+[dependencies.sile]
+path = ".."
+
+[features]
+lua54 = [ "mlua/lua54" ]
+lua53 = [ "mlua/lua53" ]
+lua52 = [ "mlua/lua52" ]
+lua51 = [ "mlua/lua51" ]
+luajit = [ "mlua/luajit" ]
+
+[dependencies.mlua]
+version = "0.9"
+features = [ "module" ]

rusile/src/lib.rs

@@ -0,0 +1,19 @@
+#![crate_type = "cdylib"]
+#![crate_type = "rlib"]
+#![crate_type = "staticlib"]
+
+use mlua::prelude::*;
+use sile::rusile_demo;
+
+#[mlua::lua_module]
+fn rusile(lua: &Lua) -> LuaResult<LuaTable> {
+    let exports = lua.create_table().unwrap();
+    let demo: LuaFunction = lua.create_function(demo).unwrap();
+    exports.set("demo", demo)?;
+    Ok(exports)
+}
+
+fn demo(lua: &Lua, (): ()) -> LuaResult<LuaString> {
+    let res = rusile_demo().unwrap();
+    lua.create_string(res)
+}

spec/rusile_spec.lua

@@ -0,0 +1,16 @@
+SILE = require("core.sile")
+
+describe("rusile", function ()
+
+   it("should exist", function ()
+      assert.is.truthy(SILE._rusile)
+   end)
+
+   describe("demo ", function ()
+      it("should return a test string", function ()
+         local str = "Hello from rusile"
+         assert.is.equal(str, SILE._rusile.demo())
+      end)
+   end)
+
+end)

src/embed.rs.in

@@ -31,6 +31,7 @@ pub struct SileModules;
 // Link Lua loader functions from C modules that Lua would otherwise be loading externally that
 // we've linked into the CLI binary. Linking happens in build-aux/build.rs.
 extern "C-unwind" {
+    fn luaopen_rusile(lua: *mut mlua::lua_State) -> i32;
     fn luaopen_fontmetrics(lua: *mut mlua::lua_State) -> i32;
     fn luaopen_justenoughfontconfig(lua: *mut mlua::lua_State) -> i32;
     fn luaopen_justenoughharfbuzz(lua: *mut mlua::lua_State) -> i32;
@@ -52,6 +53,9 @@ pub fn inject_embedded_loader(lua: &Lua) {
     loaders
         .push(LuaFunction::wrap(|lua, module: String| unsafe {
             match module.as_str() {
+                "rusile" => lua
+                    .create_c_function(luaopen_rusile)
+                    .map(LuaValue::Function),
                 "fontmetrics" => lua
                     .create_c_function(luaopen_fontmetrics)
                     .map(LuaValue::Function),

src/lib.rs

@@ -200,3 +200,7 @@ fn path_to_string(path: &PathBuf) -> String {
 fn paths_to_strings(paths: Vec<PathBuf>) -> Vec<String> {
     paths.iter().map(path_to_string).collect()
 }
+
+pub fn rusile_demo() -> Result<String> {
+    Ok("Hello from rusile".to_string())
+}