macro

3 files changed, 681 insertions, 4 deletions

diff --git a/src/ast/ast.js b/src/ast/ast.js
new file mode 100644
index 000000000..06be333c5
--- /dev/null
+++ b/src/ast/ast.js
@@ -0,0 +1,106 @@
+globalThis.BunASTNode ??= class BunASTNode {
+  position = -1;
+};
+
+if (!globalThis.BunAST) {
+  globalThis.BunAST = {
+    EArray: class EArray extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EUnary: class EUnary extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EBinary: class EBinary extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EClass: class EClass extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ENew: class ENew extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EFunction: class EFunction extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ECall: class ECall extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EDot: class EDot extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EIndex: class EIndex extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EArrow: class EArrow extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EIdentifier: class EIdentifier extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EImportIdentifier: class EImportIdentifier extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EPrivateIdentifier: class EPrivateIdentifier extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EJsxElement: class EJsxElement extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EObject: class EObject extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ESpread: class ESpread extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ETemplatePart: class ETemplatePart extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ETemplate: class ETemplate extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ERegExp: class ERegExp extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EAwait: class EAwait extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EYield: class EYield extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EIf: class EIf extends BunASTNode {
+      no = Number.MAX_SAFE_INTEGER;
+      yes = Number.MAX_SAFE_INTEGER;
+    },
+    ERequire: class ERequire extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EImport: class EImport extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EBoolean: class EBoolean extends BunASTNode {
+      val = false;
+    },
+    ENumber: class ENumber extends BunASTNode {
+      val = 0;
+    },
+    EBigInt: class EBigInt extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EString: class EString extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EMissing: class EMissing extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EThis: class EThis extends BunASTNode {},
+    ESuper: class ESuper extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    ENull: class ENull extends BunASTNode {},
+    EUndefined: class EUndefined extends BunASTNode {},
+    ENewTarget: class ENewTarget extends BunASTNode {
+      #ptr = Number.MAX_SAFE_INTEGER;
+    },
+    EImportMeta: class EImportMeta extends BunASTNode {},
+  };
+}
diff --git a/src/bundler.zig b/src/bundler.zig
index 77534e602..ef38f7d96 100644
--- a/src/bundler.zig
+++ b/src/bundler.zig
@@ -123,6 +123,8 @@ pub const Bundler = struct {
     // must be pointer array because we can't we don't want the source to point to invalid memory if the array size is reallocated
     virtual_modules: std.ArrayList(*ClientEntryPoint),
 
+    macro_context: ?*js_ast.Macro.MacroContext = null,
+
     pub const isCacheEnabled = cache_files;
 
     pub fn clone(this: *ThisBundler, allocator: *std.mem.Allocator, to: *ThisBundler) !void {
@@ -2412,6 +2414,13 @@ pub const Bundler = struct {
                     bundler.options.jsx.supports_fast_refresh;
                 opts.filepath_hash_for_hmr = file_hash orelse 0;
                 opts.warn_about_unbundled_modules = bundler.options.platform != .bun;
+
+                if (bundler.macro_context == null) {
+                    bundler.macro_context = js_ast.Macro.MacroContext.init(bundler);
+                }
+
+                opts.macro_context = &bundler.macro_context.?;
+
                 const value = (bundler.resolver.caches.js.parse(
                     allocator,
                     opts,
@@ -3317,3 +3326,72 @@ pub const ResolveQueue = std.fifo.LinearFifo(
     _resolver.Result,
     std.fifo.LinearFifoBufferType.Dynamic,
 );
+
+// This is not very fast.
+// The idea is: we want to generate a unique entry point per macro function export that registers the macro
+// Registering the macro happens in VirtualMachine
+// We "register" it which just marks the JSValue as protected.
+// This is mostly a workaround for being unable to call ESM exported functions from C++.
+// When that is resolved, we should remove this.
+pub const MacroEntryPoint = struct {
+    code_buffer: [std.fs.MAX_PATH_BYTES * 2 + 500]u8 = undefined,
+    output_code_buffer: [std.fs.MAX_PATH_BYTES * 8 + 500]u8 = undefined,
+    source: logger.Source = undefined,
+
+    pub fn generateID(entry_path: string, function_name: string, buf: []u8, len: *u32) i32 {
+        var hasher = std.hash.Wyhash.init(0);
+        hasher.update(js_ast.Macro.namespaceWithColon);
+        hasher.update(entry_path);
+        hasher.update(function_name);
+        const truncated_u32 = @truncate(u32, hasher.final());
+
+        const specifier = std.fmt.bufPrint(buf, js_ast.Macro.namespaceWithColon ++ "//{x}.js", .{truncated_u32}) catch unreachable;
+        len.* = @truncate(u32, specifier.len);
+
+        return generateIDFromSpecifier(specifier);
+    }
+
+    pub fn generateIDFromSpecifier(specifier: string) i32 {
+        return @bitCast(i32, @truncate(u32, std.hash.Wyhash.hash(0, specifier)));
+    }
+
+    pub fn generate(
+        entry: *MacroEntryPoint,
+        bundler: *Bundler,
+        import_path: Fs.PathName,
+        function_name: string,
+        macro_id: i32,
+        macro_label_: string,
+    ) !void {
+        const dir_to_use: string = import_path.dirWithTrailingSlash();
+        std.mem.copy(u8, entry.code_buffer[0..macro_label_.len], macro_label_);
+        const macro_label = entry.code_buffer[0..macro_label_.len];
+
+        const code = try std.fmt.bufPrint(
+            entry.code_buffer[macro_label.len..],
+            \\//Auto-generated file
+            \\import * as Macros from '{s}{s}';
+            \\
+            \\if (!('{s}' in Macros)) {{
+            \\  throw new Error("Macro '{s}' not found in '{s}{s}'");
+            \\}}
+            \\
+            \\Bun.registerMacro({d}, Macros['{s}']);
+        ,
+            .{
+                dir_to_use,
+                import_path.filename,
+                function_name,
+                function_name,
+                dir_to_use,
+                import_path.filename,
+                macro_id,
+                function_name,
+            },
+        );
+
+        entry.source = logger.Source.initPathString(macro_label, code);
+        entry.source.path.text = macro_label;
+        entry.source.path.namespace = js_ast.Macro.namespace;
+    }
+};
diff --git a/src/js_ast.zig b/src/js_ast.zig
index 0b98d1a38..9ddafdf80 100644
--- a/src/js_ast.zig
+++ b/src/js_ast.zig
@@ -321,7 +321,7 @@ pub const Binding = struct {
             *B.Object => {
                 return Binding{ .loc = loc, .data = B{ .b_object = t } };
             },
-            *B.Missing => {
+            B.Missing => {
                 return Binding{ .loc = loc, .data = B{ .b_missing = t } };
             },
             else => {
@@ -1700,6 +1700,7 @@ pub const Stmt = struct {
             pub const All = NewBaseStore(Union, 128);
 
             threadlocal var has_inited = false;
+            pub threadlocal var disable_reset = false;
             pub fn create(allocator: *std.mem.Allocator) void {
                 if (has_inited) {
                     return;
@@ -1710,6 +1711,7 @@ pub const Stmt = struct {
             }
 
             pub fn reset() void {
+                if (disable_reset) return;
                 All.reset();
             }
 
@@ -2367,7 +2369,7 @@ pub const Expr = struct {
                 return Expr{
                     .loc = loc,
                     .data = Data{
-                        .e_number = Data.Store.All.append(Type, st),
+                        .e_number = st,
                     },
                 };
             },
@@ -2542,8 +2544,160 @@ pub const Expr = struct {
         e_class,
         e_require,
 
+        pub inline fn toPublicValue(this: Tag) u16 {
+            return @intCast(u16, @enumToInt(this)) + 16;
+        }
+
+        pub inline fn fromPublicValue(comptime ValueType: type, value: ValueType) ?Tag {
+            if (value < 16 or value > @enumToInt(Tag.e_require)) return null;
+
+            switch (comptime ValueType) {
+                f64 => {
+                    return @intToEnum(@floatToInt(u16, value - 16), Tag);
+                },
+                else => {
+                    return @intToEnum(@intCast(u6, @intCast(u16, value) - 16), Tag);
+                },
+            }
+        }
+
+        pub const names_strings = [_]string{
+            "<array>",
+            "<unary>",
+            "<binary>",
+            "<boolean>",
+            "<super>",
+            "<null>",
+            "<void>",
+            "<new>",
+            "<function>",
+            "<ntarget>",
+            "<import>",
+            "<call>",
+            "<dot>",
+            "<index>",
+            "<arrow>",
+            "<id>",
+            "<importid>",
+            "<private>",
+            "<jsx>",
+            "<missing>",
+            "<number>",
+            "<bigint>",
+            "<object>",
+            "<spread>",
+            "<string>",
+            "<tpart>",
+            "<template>",
+            "<regexp>",
+            "<await>",
+            "<yield>",
+            "<if>",
+            "<resolve>",
+            "<import>",
+            "<this>",
+            "<class>",
+            "<require>",
+        };
+        pub const valid_names_list: string = brk: {
+            var names_list = names_strings[0];
+            for (names_strings[1..]) |name_str, i| {
+                names_list = names_list ++ "\n  " ++ name_str;
+            }
+            break :brk "  " ++ names_list;
+        };
+
+        pub const TagName = std.EnumArray(Tag, string);
+
+        pub const names: TagName = brk: {
+            var array = TagName.initUndefined();
+            array.set(.e_array, names_strings[0]);
+            array.set(.e_unary, names_strings[1]);
+            array.set(.e_binary, names_strings[2]);
+            array.set(.e_boolean, names_strings[3]);
+            array.set(.e_super, names_strings[4]);
+            array.set(.e_null, names_strings[5]);
+            array.set(.e_undefined, names_strings[6]);
+            array.set(.e_new, names_strings[7]);
+            array.set(.e_function, names_strings[8]);
+            array.set(.e_new_target, names_strings[9]);
+            array.set(.e_import_meta, names_strings[10]);
+            array.set(.e_call, names_strings[11]);
+            array.set(.e_dot, names_strings[12]);
+            array.set(.e_index, names_strings[13]);
+            array.set(.e_arrow, names_strings[14]);
+            array.set(.e_identifier, names_strings[15]);
+            array.set(.e_import_identifier, names_strings[16]);
+            array.set(.e_private_identifier, names_strings[17]);
+            array.set(.e_jsx_element, names_strings[18]);
+            array.set(.e_missing, names_strings[19]);
+            array.set(.e_number, names_strings[20]);
+            array.set(.e_big_int, names_strings[21]);
+            array.set(.e_object, names_strings[22]);
+            array.set(.e_spread, names_strings[23]);
+            array.set(.e_string, names_strings[24]);
+            array.set(.e_template_part, names_strings[25]);
+            array.set(.e_template, names_strings[26]);
+            array.set(.e_reg_exp, names_strings[27]);
+            array.set(.e_await, names_strings[28]);
+            array.set(.e_yield, names_strings[29]);
+            array.set(.e_if, names_strings[30]);
+            array.set(.e_require_or_require_resolve, names_strings[31]);
+            array.set(.e_import, names_strings[32]);
+            array.set(.e_this, names_strings[33]);
+            array.set(.e_class, names_strings[34]);
+            array.set(.e_require, names_strings[35]);
+            break :brk array;
+        };
+        pub const TagExactSizeMatcher = strings.ExactSizeMatcher(8);
+        pub fn find(name_: string) ?Tag {
+            return switch (TagExactSizeMatcher.match(name_)) {
+                TagExactSizeMatcher.case("array") => Tag.e_array,
+                TagExactSizeMatcher.case("unary") => Tag.e_unary,
+                TagExactSizeMatcher.case("binary") => Tag.e_binary,
+                TagExactSizeMatcher.case("boolean") => Tag.e_boolean,
+                TagExactSizeMatcher.case("true") => Tag.e_boolean,
+                TagExactSizeMatcher.case("false") => Tag.e_boolean,
+                TagExactSizeMatcher.case("super") => Tag.e_super,
+                TagExactSizeMatcher.case("null") => Tag.e_null,
+                TagExactSizeMatcher.case("void") => Tag.e_undefined,
+                TagExactSizeMatcher.case("new") => Tag.e_new,
+                TagExactSizeMatcher.case("function") => Tag.e_function,
+                TagExactSizeMatcher.case("ntarget") => Tag.e_new_target,
+                TagExactSizeMatcher.case("imeta") => Tag.e_import_meta,
+                TagExactSizeMatcher.case("call") => Tag.e_call,
+                TagExactSizeMatcher.case("dot") => Tag.e_dot,
+                TagExactSizeMatcher.case("index") => Tag.e_index,
+                TagExactSizeMatcher.case("arrow") => Tag.e_arrow,
+                TagExactSizeMatcher.case("id") => Tag.e_identifier,
+                TagExactSizeMatcher.case("importid") => Tag.e_import_identifier,
+                TagExactSizeMatcher.case("jsx") => Tag.e_jsx_element,
+                TagExactSizeMatcher.case("missing") => Tag.e_missing,
+                TagExactSizeMatcher.case("number") => Tag.e_number,
+                TagExactSizeMatcher.case("bigint") => Tag.e_big_int,
+                TagExactSizeMatcher.case("object") => Tag.e_object,
+                TagExactSizeMatcher.case("spread") => Tag.e_spread,
+                TagExactSizeMatcher.case("string") => Tag.e_string,
+                TagExactSizeMatcher.case("tpart") => Tag.e_template_part,
+                TagExactSizeMatcher.case("template") => Tag.e_template,
+                TagExactSizeMatcher.case("regexp") => Tag.e_reg_exp,
+                TagExactSizeMatcher.case("await") => Tag.e_await,
+                TagExactSizeMatcher.case("yield") => Tag.e_yield,
+                TagExactSizeMatcher.case("if") => Tag.e_if,
+                TagExactSizeMatcher.case("import") => Tag.e_import,
+                TagExactSizeMatcher.case("this") => Tag.e_this,
+                TagExactSizeMatcher.case("class") => Tag.e_class,
+                TagExactSizeMatcher.case("require") => Tag.e_require,
+                else => null,
+            };
+        }
+
+        pub inline fn name(this: Tag) string {
+            return names.get(this);
+        }
+
         pub fn jsonStringify(self: @This(), opts: anytype, o: anytype) !void {
-            return try std.json.stringify(@tagName(self), opts, o);
+            return try std.json.stringify(self.name(), opts, o);
         }
 
         pub fn isArray(self: Tag) bool {
@@ -3074,7 +3228,7 @@ pub const Expr = struct {
         e_import: *E.Import,
 
         e_boolean: E.Boolean,
-        e_number: *E.Number,
+        e_number: E.Number,
         e_big_int: *E.BigInt,
         e_string: *E.String,
 
@@ -3129,6 +3283,7 @@ pub const Expr = struct {
             );
 
             threadlocal var has_inited = false;
+            pub threadlocal var disable_reset = false;
             pub fn create(allocator: *std.mem.Allocator) void {
                 if (has_inited) {
                     return;
@@ -3140,6 +3295,7 @@ pub const Expr = struct {
             }
 
             pub fn reset() void {
+                if (disable_reset) return;
                 All.reset();
                 Identifier.reset();
             }
@@ -3921,6 +4077,343 @@ pub fn printmem(comptime format: string, args: anytype) void {
     // Output.print(format, args);
 }
 
+pub const Macro = struct {
+    const JavaScript = @import("./javascript/jsc/javascript.zig");
+    const JSC = @import("./javascript/jsc/bindings/bindings.zig");
+    const JSCBase = @import("./javascript/jsc/base.zig");
+    const Resolver = @import("./resolver/resolver.zig").Resolver;
+    const isPackagePath = @import("./resolver/resolver.zig").isPackagePath;
+    const ResolveResult = @import("./resolver/resolver.zig").Result;
+    const DotEnv = @import("./env_loader.zig");
+    const js = @import("./javascript/jsc/JavascriptCore.zig");
+    const Zig = @import("./javascript/jsc/bindings/exports.zig");
+    const Bundler = @import("./bundler.zig").Bundler;
+    const MacroEntryPoint = @import("./bundler.zig").MacroEntryPoint;
+
+    pub const namespace: string = "macro";
+    pub const namespaceWithColon: string = namespace ++ ":";
+
+    pub fn isMacroPath(str: string) bool {
+        return (str.len > namespaceWithColon.len and strings.eqlComptimeIgnoreLen(str[0..namespaceWithColon.len], namespaceWithColon));
+    }
+
+    pub const MacroContext = struct {
+        pub const MacroMap = std.AutoArrayHashMap(i32, Macro);
+
+        resolver: *Resolver,
+        env: *DotEnv.Loader,
+        macros: MacroMap,
+
+        pub fn init(bundler: *Bundler) MacroContext {
+            return MacroContext{
+                .macros = MacroMap.init(default_allocator),
+                .resolver = &bundler.resolver,
+                .env = bundler.env,
+            };
+        }
+
+        pub fn call(
+            this: *MacroContext,
+            import_record_path: string,
+            source_dir: string,
+            log: *logger.Log,
+            source: *const logger.Source,
+            import_range: logger.Range,
+            caller: Expr,
+            args: []Expr,
+            function_name: string,
+        ) anyerror!Expr {
+            Expr.Data.Store.disable_reset = true;
+            Stmt.Data.Store.disable_reset = true;
+            defer Expr.Data.Store.disable_reset = false;
+            defer Stmt.Data.Store.disable_reset = false;
+            // const is_package_path = isPackagePath(specifier);
+            std.debug.assert(isMacroPath(import_record_path));
+
+            const resolve_result = this.resolver.resolve(source_dir, import_record_path[namespaceWithColon.len..], .stmt) catch |err| {
+                switch (err) {
+                    error.ModuleNotFound => {
+                        log.addResolveError(
+                            source,
+                            import_range,
+                            log.msgs.allocator,
+                            "Macro \"{s}\" not found",
+                            .{import_record_path},
+                            .stmt,
+                        ) catch unreachable;
+                        return error.MacroNotFound;
+                    },
+                    else => {
+                        log.addRangeErrorFmt(
+                            source,
+                            import_range,
+                            log.msgs.allocator,
+                            "{s} resolving macro \"{s}\"",
+                            .{ @errorName(err), import_record_path },
+                        ) catch unreachable;
+                        return err;
+                    },
+                }
+            };
+
+            var specifier_buf: [64]u8 = undefined;
+            var specifier_buf_len: u32 = 0;
+            const hash = MacroEntryPoint.generateID(
+                resolve_result.path_pair.primary.text,
+                function_name,
+                &specifier_buf,
+                &specifier_buf_len,
+            );
+
+            var macro_entry = this.macros.getOrPut(hash) catch unreachable;
+            if (!macro_entry.found_existing) {
+                macro_entry.value_ptr.* = Macro.init(
+                    default_allocator,
+                    this.resolver,
+                    resolve_result,
+                    log,
+                    this.env,
+                    function_name,
+                    specifier_buf[0..specifier_buf_len],
+                    hash,
+                ) catch |err| {
+                    macro_entry.value_ptr.* = Macro{ .resolver = undefined, .disabled = true };
+                    return err;
+                };
+                Output.flush();
+            }
+            defer Output.flush();
+
+            const macro = macro_entry.value_ptr.*;
+            if (macro.disabled) {
+                return caller;
+            }
+            macro.vm.enableMacroMode();
+            defer macro.vm.disableMacroMode();
+            return Macro.Runner.run(
+                macro,
+                log,
+                default_allocator,
+                function_name,
+                caller,
+                args,
+                source,
+                hash,
+            );
+            // this.macros.getOrPut(key: K)
+        }
+    };
+
+    pub const JSExpr = struct {
+        expr: Expr,
+        pub const Class = JSCBase.NewClass(
+            JSExpr,
+            .{
+                .name = "JSExpr",
+                .read_only = true,
+            },
+            .{
+                .toString = .{
+                    .rfn = toString,
+                },
+                // .toNumber = .{
+                //     .rfn = toNumber,
+                // },
+            },
+            .{
+                .tag = .{
+                    .get = getTag,
+                    .ro = true,
+                },
+                .tagName = .{
+                    .get = getTagName,
+                    .ro = true,
+                },
+                .position = .{
+                    .get = getPosition,
+                    .ro = true,
+                },
+            },
+        );
+
+        // pub fn isInstanceOf(
+        //     ctx: js.JSContextRef,
+        //     obj: js.JSObjectRef,
+        //     value: js.JSValueRef,
+        //     exception: js.ExceptionRef,
+        // ) bool {
+        //     js.JSValueToNumber(ctx, value, exception);
+        // }
+
+        pub fn toString(
+            this: *JSExpr,
+            ctx: js.JSContextRef,
+            function: js.JSObjectRef,
+            thisObject: js.JSObjectRef,
+            arguments: []const js.JSValueRef,
+            exception: js.ExceptionRef,
+        ) js.JSObjectRef {
+            switch (this.expr.data) {
+                .e_string => |str| {
+                    if (str.isBlank()) {
+                        return JSC.ZigString.init("").toValue(JavaScript.VirtualMachine.vm.global).asRef();
+                    }
+
+                    if (str.isUTF8()) {
+                        return JSC.ZigString.init(str.utf8).toValue(JavaScript.VirtualMachine.vm.global).asRef();
+                    } else {
+                        return js.JSValueMakeString(ctx, js.JSStringCreateWithCharactersNoCopy(str.value.ptr, str.value.len));
+                    }
+                },
+                .e_template => |template| {
+                    const str = template.head;
+
+                    if (str.isBlank()) {
+                        return JSC.ZigString.init("").toValue(JavaScript.VirtualMachine.vm.global).asRef();
+                    }
+
+                    if (str.isUTF8()) {
+                        return JSC.ZigString.init(str.utf8).toValue(JavaScript.VirtualMachine.vm.global).asRef();
+                    } else {
+                        return js.JSValueMakeString(ctx, js.JSStringCreateWithCharactersNoCopy(str.value.ptr, str.value.len));
+                    }
+                },
+                else => {
+                    return JSC.ZigString.init("").toValue(JavaScript.VirtualMachine.vm.global).asRef();
+                },
+            }
+        }
+
+        pub fn getTag(
+            this: *JSExpr,
+            ctx: js.JSContextRef,
+            thisObject: js.JSValueRef,
+            prop: js.JSStringRef,
+            exception: js.ExceptionRef,
+        ) js.JSObjectRef {
+            return JSC.JSValue.jsNumberFromU16(@intCast(u16, @enumToInt(std.meta.activeTag(this.expr.data)))).asRef();
+        }
+        pub fn getTagName(
+            this: *JSExpr,
+            ctx: js.JSContextRef,
+            thisObject: js.JSValueRef,
+            prop: js.JSStringRef,
+            exception: js.ExceptionRef,
+        ) js.JSObjectRef {
+            return JSC.ZigString.init(@tagName(this.expr.data)).toValue(JavaScript.VirtualMachine.vm.global).asRef();
+        }
+        pub fn getPosition(
+            this: *JSExpr,
+            ctx: js.JSContextRef,
+            thisObject: js.JSValueRef,
+            prop: js.JSStringRef,
+            exception: js.ExceptionRef,
+        ) js.JSObjectRef {
+            return JSC.JSValue.jsNumberFromInt32(this.expr.loc.start).asRef();
+        }
+    };
+
+    resolver: *Resolver,
+    vm: *JavaScript.VirtualMachine = undefined,
+
+    resolved: ResolveResult = undefined,
+    disabled: bool = false,
+
+    pub fn init(
+        allocator: *std.mem.Allocator,
+        resolver: *Resolver,
+        resolved: ResolveResult,
+        log: *logger.Log,
+        env: *DotEnv.Loader,
+        function_name: string,
+        specifier: string,
+        hash: i32,
+    ) !Macro {
+        const path = resolved.path_pair.primary;
+
+        var vm: *JavaScript.VirtualMachine = if (JavaScript.VirtualMachine.vm_loaded)
+            JavaScript.VirtualMachine.vm
+        else brk: {
+            var _vm = try JavaScript.VirtualMachine.init(default_allocator, resolver.opts.transform_options, null, log, env);
+            _vm.enableMacroMode();
+
+            _vm.bundler.configureLinker();
+            _vm.bundler.configureDefines() catch unreachable;
+            break :brk _vm;
+        };
+
+        vm.enableMacroMode();
+
+        var loaded_result = try vm.loadMacroEntryPoint(path.text, function_name, specifier, hash);
+
+        if (loaded_result.status(vm.global.vm()) == JSC.JSPromise.Status.Rejected) {
+            vm.defaultErrorHandler(loaded_result.result(vm.global.vm()), null);
+            vm.disableMacroMode();
+            return error.MacroLoadError;
+        }
+
+        JavaScript.VirtualMachine.vm_loaded = true;
+
+        // We don't need to do anything with the result.
+        // We just want to make sure the promise is finished.
+        _ = loaded_result.result(vm.global.vm());
+
+        return Macro{
+            .vm = vm,
+            .resolved = resolved,
+            .resolver = resolver,
+        };
+    }
+
+    pub const Runner = struct {
+        threadlocal var args_buf: [32]js.JSObjectRef = undefined;
+        threadlocal var expr_nodes_buf: [32]JSExpr = undefined;
+        threadlocal var exception_holder: Zig.ZigException.Holder = undefined;
+        pub fn run(
+            macro: Macro,
+            log: *logger.Log,
+            allocator: *std.mem.Allocator,
+            function_name: string,
+            caller: Expr,
+            args: []Expr,
+            source: *const logger.Source,
+            id: i32,
+        ) Expr {
+            if (comptime isDebug) Output.prettyln("<r><d>[macro]<r> call <d><b>{s}<r>", .{function_name});
+
+            exception_holder = Zig.ZigException.Holder.init();
+            expr_nodes_buf[0] = JSExpr{ .expr = caller };
+            args_buf[0] = JSExpr.Class.make(
+                macro.vm.global.ref(),
+                &expr_nodes_buf[0],
+            );
+            for (args) |arg, i| {
+                expr_nodes_buf[i + 1] = JSExpr{ .expr = arg };
+                args_buf[i + 1] =
+                    JSExpr.Class.make(
+                    macro.vm.global.ref(),
+                    &expr_nodes_buf[i + 1],
+                );
+            }
+            args_buf[args.len + 2] = null;
+
+            var macro_callback = macro.vm.macros.get(id) orelse return caller;
+            var result = js.JSObjectCallAsFunctionReturnValue(macro.vm.global.ref(), macro_callback, null, args.len + 1, &args_buf);
+            var promise = JSC.JSPromise.resolvedPromise(macro.vm.global, result);
+            macro.vm.global.vm().drainMicrotasks();
+
+            if (promise.status(macro.vm.global.vm()) == .Rejected) {
+                macro.vm.defaultErrorHandler(promise.result(macro.vm.global.vm()), null);
+                return caller;
+            }
+
+            const value = promise.result(macro.vm.global.vm());
+
+            return caller;
+        }
+    };
+};
+
 test "Binding.init" {
     var binding = Binding.alloc(
         std.heap.page_allocator,