include and link lua 5.4, smoke test in panto cli main.zig

1 files changed, 69 insertions, 0 deletions

diff --git a/build.zig b/build.zig
index 5d4cdb6..e675859 100644
--- a/build.zig
+++ b/build.zig
@@ -9,13 +9,21 @@ pub fn build(b: *std.Build) void {
         .optimize = optimize,
     });
 
+    // Fetch upstream Lua 5.4.7 (source-only tarball from lua.org).
+    // Reproducibility comes from the content-addressed hash in build.zig.zon.
+    const lua_src = b.dependency("lua_src", .{});
+    const lua = buildLua(b, target, optimize, lua_src);
+
     // CLI executable
     const exe_mod = b.createModule(.{
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
+        .link_libc = true,
     });
     exe_mod.addImport("panto", panto_lib_dep.module("panto"));
+    exe_mod.linkLibrary(lua);
+    exe_mod.addIncludePath(lua_src.path("src"));
 
     const exe = b.addExecutable(.{
         .name = "panto",
@@ -38,8 +46,11 @@ pub fn build(b: *std.Build) void {
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
+        .link_libc = true,
     });
     test_mod.addImport("panto", panto_lib_dep.module("panto"));
+    test_mod.linkLibrary(lua);
+    test_mod.addIncludePath(lua_src.path("src"));
 
     const unit_tests = b.addTest(.{
         .name = "panto-tests",
@@ -54,3 +65,61 @@ pub fn build(b: *std.Build) void {
     const lib_test_step = panto_lib_dep.builder.top_level_steps.get("test").?;
     test_step.dependOn(&lib_test_step.step);
 }
+
+/// Compile Lua 5.4.7 as a static library against the upstream source tarball.
+/// Excludes `lua.c` (interpreter REPL) and `luac.c` (bytecode compiler) — we
+/// only want the embedded library.
+fn buildLua(
+    b: *std.Build,
+    target: std.Build.ResolvedTarget,
+    optimize: std.builtin.OptimizeMode,
+    lua_src: *std.Build.Dependency,
+) *std.Build.Step.Compile {
+    const lua_mod = b.createModule(.{
+        .target = target,
+        .optimize = optimize,
+        .link_libc = true,
+    });
+
+    const cflags = [_][]const u8{
+        "-std=gnu99",
+        "-Wall",
+        "-Wextra",
+        "-Wno-unused-parameter",
+    };
+
+    lua_mod.addCSourceFiles(.{
+        .root = lua_src.path("src"),
+        .files = &lua_files,
+        .flags = &cflags,
+    });
+
+    // Tell Lua which platform features are available. The macros change
+    // which `dlopen`/readline/etc. paths Lua compiles in.
+    switch (target.result.os.tag) {
+        .macos => lua_mod.addCMacro("LUA_USE_MACOSX", ""),
+        .linux => lua_mod.addCMacro("LUA_USE_LINUX", ""),
+        .freebsd, .netbsd, .openbsd => lua_mod.addCMacro("LUA_USE_POSIX", ""),
+        else => {},
+    }
+
+    return b.addLibrary(.{
+        .name = "lua",
+        .linkage = .static,
+        .root_module = lua_mod,
+    });
+}
+
+// Lua 5.4.7 core VM + standard library. Excludes lua.c (interpreter entry
+// point) and luac.c (compiler entry point).
+const lua_files = [_][]const u8{
+    // Core VM
+    "lapi.c",     "lcode.c",    "lctype.c",  "ldebug.c", "ldo.c",
+    "ldump.c",    "lfunc.c",    "lgc.c",     "llex.c",   "lmem.c",
+    "lobject.c",  "lopcodes.c", "lparser.c", "lstate.c", "lstring.c",
+    "ltable.c",   "ltm.c",      "lundump.c", "lvm.c",    "lzio.c",
+    // Auxiliary + standard library
+    "lauxlib.c",  "lbaselib.c", "lcorolib.c", "ldblib.c", "liolib.c",
+    "lmathlib.c", "loadlib.c",  "loslib.c",   "lstrlib.c", "ltablib.c",
+    "lutf8lib.c", "linit.c",
+};