fix(bindings): correct Zig bindings to expose a language function

Instead of having users declare the extern function themselves, they can
pass in the language to `Language.create` in the zig bindings. If they
really want, they can always opt into the `extern fn tree_sitter_LANG()
*const ts.Language` approach.

cli/src/init.rs

@@ -97,6 +97,7 @@ const TESTS_SWIFT_TEMPLATE: &str = include_str!("./templates/tests.swift");
 
 const BUILD_ZIG_TEMPLATE: &str = include_str!("./templates/build.zig");
 const BUILD_ZIG_ZON_TEMPLATE: &str = include_str!("./templates/build.zig.zon");
+const ROOT_ZIG_TEMPLATE: &str = include_str!("./templates/root.zig");
 
 const TREE_SITTER_JSON_SCHEMA: &str =
     "https://tree-sitter.github.io/tree-sitter/assets/schemas/config.schema.json";
@@ -700,6 +701,14 @@ pub fn generate_grammar_files(
         missing_path(repo_path.join("build.zig.zon"), |path| {
             generate_file(path, BUILD_ZIG_ZON_TEMPLATE, language_name, &generate_opts)
         })?;
+
+        missing_path(bindings_dir.join("zig"), create_dir)?.apply(|path| {
+            missing_path(path.join("root.zig"), |path| {
+                generate_file(path, ROOT_ZIG_TEMPLATE, language_name, &generate_opts)
+            })?;
+
+            Ok(())
+        })?;
     }
 
     Ok(())

cli/src/templates/build.zig

@@ -39,20 +39,38 @@ pub fn build(b: *std.Build) !void {
     }
 
     lib.addIncludePath(b.path("src"));
-    lib.installHeadersDirectory(b.path("bindings/c"), ".", .{});
 
     b.installArtifact(lib);
     b.installFile("src/node-types.json", "node-types.json");
-    b.installDirectory(.{
-        .source_dir = b.path("queries"),
-        .install_dir = .prefix,
-        .install_subdir = "queries",
-        .include_extensions = &.{"scm"}
-    });
+    b.installDirectory(.{ .source_dir = b.path("queries"), .install_dir = .prefix, .install_subdir = "queries", .include_extensions = &.{"scm"} });
 
-    const test_cmd = b.addSystemCommand(&.{"tree-sitter", "test"});
-    const test_step = b.step("test", "Run parser tests");
-    test_step.dependOn(&test_cmd.step);
+    const module = b.addModule("tree-sitter-PARSER_NAME", .{
+        .root_source_file = b.path("bindings/zig/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+    module.linkLibrary(lib);
+
+    const ts_dep = b.dependency("tree-sitter", .{});
+    const ts_mod = ts_dep.module("tree-sitter");
+    module.addImport("tree-sitter", ts_mod);
+
+    // ╭─────────────────╮
+    // │      Tests      │
+    // ╰─────────────────╯
+
+    const tests = b.addTest(.{
+        .root_source_file = b.path("bindings/zig/root.zig"),
+        .target = target,
+        .optimize = optimize,
+    });
+    tests.linkLibrary(lib);
+    tests.root_module.addImport("tree-sitter", ts_mod);
+
+    const run_tests = b.addRunArtifact(tests);
+
+    const test_step = b.step("test", "Run unit tests");
+    test_step.dependOn(&run_tests.step);
 }
 
 inline fn hasScanner(dir: std.fs.Dir) bool {

cli/src/templates/build.zig.zon

@@ -1,11 +1,14 @@
 .{
-    .name = "tree_sitter_PARSER_NAME",
+    .name = "tree-sitter-PARSER_NAME",
     .version = "PARSER_VERSION",
-    .dependencies = .{},
+    .dependencies = .{ .@"tree-sitter" = .{
+        .url = "https://github.com/tree-sitter/zig-tree-sitter/archive/refs/tags/v0.25.0.tar.gz",
+        .hash = "12201a8d5e840678bbbf5128e605519c4024af422295d68e2ba2090e675328e5811d",
+    } },
     .paths = .{
         "build.zig",
         "build.zig.zon",
-        "bindings/c",
+        "bindings/zig",
         "src",
         "queries",
         "LICENSE",

cli/src/templates/root.zig

@@ -0,0 +1,19 @@
+const testing = @import("std").testing;
+
+const ts = @import("tree-sitter");
+const Language = ts.Language;
+const Parser = ts.Parser;
+
+pub extern fn tree_sitter_PARSER_NAME() callconv(.C) *const Language;
+
+pub export fn language() *const Language {
+    return tree_sitter_PARSER_NAME();
+}
+
+test "can load grammar" {
+    const parser = Parser.create();
+    defer parser.destroy();
+    try testing.expectEqual(parser.setLanguage(language()), void{});
+    try testing.expectEqual(parser.getLanguage(), tree_sitter_PARSER_NAME());
+}
+