restructure project

1 files changed, 3334 insertions, 0 deletions

diff --git a/src/z/parser/js/ast.zig.bak b/src/z/parser/js/ast.zig.bak
new file mode 100644
index 0000000..3dc29a3
--- /dev/null
+++ b/src/z/parser/js/ast.zig.bak
@@ -0,0 +1,3334 @@
+const std = @import("std");
+
+pub const Loc = struct {
+    start: usize,
+    end: usize,
+};
+
+const lex = @import("lexical_grammar.zig");
+const Token = lex.Token;
+const TokenType = lex.TokenType;
+
+pub const FormatOptions = struct {
+    indent_size: usize = 4,
+};
+
+pub const Formatter = struct {
+    buf: []u8,
+    pos: usize,
+    indent_level: usize,
+    options: FormatOptions,
+
+    pub fn write(self: *@This(), s: []const u8) void {
+        @memcpy(self.buf[self.pos..][0..s.len], s);
+        self.pos += s.len;
+    }
+
+    pub fn writeChar(self: *@This(), c: u8) void {
+        self.buf[self.pos] = c;
+        self.pos += 1;
+    }
+
+    pub fn writeIndent(self: *@This()) void {
+        const spaces = self.indent_level * self.options.indent_size;
+        var i: usize = 0;
+        while (i < spaces) : (i += 1) {
+            self.writeChar(' ');
+        }
+    }
+
+    pub fn newline(self: *@This()) void {
+        self.writeChar('\n');
+    }
+};
+
+pub const ParseError = error{
+    UnexpectedToken,
+    ExpectedToken,
+    ExpectedExpression,
+    ExpectedStatement,
+    ExpectedIdentifier,
+    UnclosedString,
+    InvalidNumber,
+    InvalidEscape,
+    UnterminatedComment,
+    ExpectedParameterName,
+    ExpectedPropertyName,
+    UnterminatedTemplate,
+    InvalidAssignmentTarget,
+    TooManyTokens,
+};
+
+const BP = struct {
+    const comma = 1;
+    const assign = 2;
+    const yield = 3;
+    const conditional = 4;
+    const coalesce = 5;
+    const log_or = 6;
+    const log_and = 7;
+    const bit_or = 8;
+    const bit_xor = 9;
+    const bit_and = 10;
+    const equality = 11;
+    const relational = 12;
+    const shift = 13;
+    const additive = 14;
+    const multiplicative = 15;
+    const exponentiation = 16;
+    const unary = 17;
+    const update = 18;
+    const call = 19;
+    const member = 20;
+};
+
+pub const NodeArena = struct {
+    exprs: [8192]Expr = undefined,
+    expr_count: usize = 0,
+    stmts: [8192]Stmt = undefined,
+    stmt_count: usize = 0,
+    decls: [1024]Decl = undefined,
+    decl_count: usize = 0,
+    pats: [1024]Pat = undefined,
+    pat_count: usize = 0,
+    lits: [1024]Lit = undefined,
+    lit_count: usize = 0,
+    string_buf: [65536]u8 = undefined,
+    string_pos: usize = 0,
+
+    fn exprPtr(self: *NodeArena, data: ExprType, loc: Loc) *const Expr {
+        const idx = self.expr_count;
+        self.exprs[idx] = .{ .loc = loc, .data = data };
+        self.expr_count += 1;
+        return &self.exprs[idx];
+    }
+
+    fn stmtPtr(self: *NodeArena, data: StmtType, loc: Loc) *const Stmt {
+        const idx = self.stmt_count;
+        self.stmts[idx] = .{ .loc = loc, .data = data };
+        self.stmt_count += 1;
+        return &self.stmts[idx];
+    }
+
+    fn declPtr(self: *NodeArena, data: DeclType, loc: Loc) *const Decl {
+        const idx = self.decl_count;
+        self.decls[idx] = .{ .loc = loc, .data = data };
+        self.decl_count += 1;
+        return &self.decls[idx];
+    }
+
+    fn patPtr(self: *NodeArena, data: PatType, loc: Loc) *const Pat {
+        const idx = self.pat_count;
+        self.pats[idx] = .{ .loc = loc, .data = data };
+        self.pat_count += 1;
+        return &self.pats[idx];
+    }
+
+    fn litPtr(self: *NodeArena, data: LitType, loc: Loc) *const Lit {
+        const idx = self.lit_count;
+        self.lits[idx] = .{ .loc = loc, .data = data };
+        self.lit_count += 1;
+        return &self.lits[idx];
+    }
+};
+
+pub const Parser = struct {
+    tokens: []const Token,
+    pos: usize,
+    source: []const u8,
+    arena: *NodeArena,
+
+    pub fn init(tokens: []const Token, source: []const u8, arena: *NodeArena) @This() {
+        return .{ .tokens = tokens, .pos = 0, .source = source, .arena = arena };
+    }
+
+    fn tok(self: *@This()) Token {
+        return self.tokens[self.pos];
+    }
+
+    fn peek(self: *@This()) TokenType {
+        return self.tokens[self.pos].kind;
+    }
+
+    fn peekAt(self: *@This(), offset: usize) TokenType {
+        const idx = self.pos + offset;
+        if (idx >= self.tokens.len) return .eof;
+        return self.tokens[idx].kind;
+    }
+
+    fn advance(self: *@This()) void {
+        self.pos += 1;
+    }
+
+    fn advanceTok(self: *@This()) Token {
+        const t = self.tokens[self.pos];
+        self.pos += 1;
+        return t;
+    }
+
+    fn expect(self: *@This(), kind: TokenType) ParseError!void {
+        if (self.peek() != kind) return ParseError.ExpectedToken;
+        self.advance();
+    }
+
+    fn expectTok(self: *@This(), kind: TokenType) ParseError!Token {
+        if (self.peek() != kind) return ParseError.ExpectedToken;
+        return self.advanceTok();
+    }
+
+    fn match(self: *@This(), kind: TokenType) bool {
+        if (self.peek() == kind) {
+            _ = self.advanceTok();
+            return true;
+        }
+        return false;
+    }
+
+    fn matchKeyword(self: *@This(), kw: TokenType) bool {
+        if (self.peek() == kw) {
+            _ = self.advanceTok();
+            return true;
+        }
+        return false;
+    }
+
+    fn isLineTerminatorBeforeNext(self: *@This()) bool {
+        if (self.pos == 0) return false;
+        const prev_token = self.tokens[self.pos - 1];
+        const next_token = self.tokens[self.pos];
+        var i = prev_token.loc.end;
+        while (i < next_token.loc.start) : (i += 1) {
+            if (i >= self.source.len) break;
+            const c = self.source[i];
+            switch (c) {
+                '\n', '\r' => return true,
+                else => {},
+            }
+        }
+        return false;
+    }
+
+    fn as_identifier(self: *@This(), t: Token) []const u8 {
+        return self.source[t.loc.start..t.loc.end];
+    }
+
+    fn tokenSlice(self: *@This(), t: Token) []const u8 {
+        return self.source[t.loc.start..t.loc.end];
+    }
+
+    pub fn parseProgram(self: *@This()) ParseError!Program {
+        var stmts: [2048]Stmt = undefined;
+        var count: usize = 0;
+
+        while (self.peek() != .eof) {
+            const item = try self.parseStatementListItem();
+            stmts[count] = item;
+            count += 1;
+            if (count >= stmts.len) return ParseError.TooManyTokens;
+        }
+
+        const body = stmts[0..count];
+        const loc: Loc = if (body.len > 0) .{ .start = body[0].loc.start, .end = body[body.len - 1].loc.end } else .{ .start = 0, .end = 0 };
+
+        return .{ .body = body, .loc = loc };
+    }
+
+    fn parseStatementListItem(self: *@This()) ParseError!Stmt {
+        switch (self.peek()) {
+            .function => return (try self.parseFunctionDecl(.normal, .stmt)).?,
+            .async => {
+                if (self.peekAt(1) == .function) {
+                    return (try self.parseFunctionDecl(.async, .stmt)).?;
+                }
+                if (self.peekAt(1) == .@"*" and self.peekAt(2) == .function) {
+                    return (try self.parseFunctionDecl(.async_generator, .stmt)).?;
+                }
+                return self.parseStatement();
+            },
+            .class => return (try self.parseClassDecl(.stmt)).?,
+            .@"const", .let => return self.parseLexicalDecl(),
+            .@"var" => return self.parseVarStmt(),
+            .using => return self.parseUsingStmt(),
+            .import => return try self.parseImport(),
+            .@"export" => return try self.parseExport(),
+            else => return self.parseStatement(),
+        }
+    }
+
+    fn parseStatement(self: *@This()) ParseError!Stmt {
+        switch (self.peek()) {
+            .lbrace => return self.parseBlock(),
+            .semicolon => {
+                const t = self.advanceTok();
+                return Stmt{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .data = .{ .empty = {} } };
+            },
+            .@"if" => return self.parseIf(),
+            .@"while" => return self.parseWhile(),
+            .do => return self.parseDoWhile(),
+            .@"for" => return self.parseFor(),
+            .@"continue" => return self.parseContinue(),
+            .@"break" => return self.parseBreak(),
+            .@"return" => return self.parseReturn(),
+            .@"switch" => return self.parseSwitch(),
+            .throw => return self.parseThrow(),
+            .@"try" => return self.parseTry(),
+            .debugger => {
+                const t = self.advanceTok();
+                self.semicolon();
+                return Stmt{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .data = .{ .debugger = {} } };
+            },
+            .with => return self.parseWith(),
+            .function => return (try self.parseFunctionDecl(.normal, .stmt)).?,
+            .async => {
+                if (self.peekAt(1) == .function) {
+                    return (try self.parseFunctionDecl(.async, .stmt)).?;
+                }
+                if (self.peekAt(1) == .@"*") return self.parseExpressionStatement();
+                if (self.peekAt(1).isIdentifier()) {
+                    return self.parseExpressionStatement();
+                }
+                return self.parseExpressionStatement();
+            },
+            .class => return (try self.parseClassDecl(.stmt)).?,
+            .@"const", .let => return self.parseLexicalDecl(),
+            .@"var" => return self.parseVarStmt(),
+            .import => return try self.parseImport(),
+            .@"export" => return try self.parseExport(),
+            else => return self.parseExpressionStatement(),
+        }
+    }
+
+    fn parseBlock(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var stmts: [1024]Stmt = undefined;
+        var count: usize = 0;
+
+        while (self.peek() != .rbrace and self.peek() != .eof) {
+            const s = try self.parseStatementListItem();
+            stmts[count] = s;
+            count += 1;
+            if (count >= stmts.len) return ParseError.TooManyTokens;
+        }
+
+        const end_tok = try self.expectTok(.rbrace);
+        const end = end_tok.loc.end;
+
+        const block = Stmt{
+            .loc = .{ .start = start, .end = end },
+            .data = .{ .block = .{ .loc = .{ .start = start, .end = end }, .body = stmts[0..count] } },
+        };
+        return block;
+    }
+
+    fn parseIf(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        try self.expect(.lparen);
+        const condition = try self.parseExpr(0);
+        try self.expect(.rparen);
+        const consequent = try self.statementPointer();
+        var alternate: ?*const Stmt = null;
+        if (self.matchKeyword(.@"else")) {
+            alternate = try self.statementPointer();
+        }
+        const end = if (alternate) |a| a.loc.end else consequent.loc.end;
+        return Stmt{
+            .loc = .{ .start = start, .end = end },
+            .data = .{ .@"if" = .{ .loc = .{ .start = start, .end = end }, .condition = condition, .consequent = consequent, .alternate = alternate } },
+        };
+    }
+
+    fn parseWhile(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        try self.expect(.lparen);
+        const condition = try self.parseExpr(0);
+        try self.expect(.rparen);
+        const body = try self.statementPointer();
+        return Stmt{
+            .loc = .{ .start = start, .end = body.loc.end },
+            .data = .{ .@"while" = .{ .loc = .{ .start = start, .end = body.loc.end }, .condition = condition, .body = body } },
+        };
+    }
+
+    fn parseDoWhile(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        const body = try self.statementPointer();
+        try self.expect(.@"while");
+        try self.expect(.lparen);
+        const condition = try self.parseExpr(0);
+        try self.expect(.rparen);
+        self.semicolon();
+        return Stmt{
+            .loc = .{ .start = start, .end = condition.loc.end },
+            .data = .{ .do_while = .{ .loc = .{ .start = start, .end = condition.loc.end }, .body = body, .condition = condition } },
+        };
+    }
+
+    fn parseFor(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        try self.expect(.lparen);
+
+        var for_init: ?ForInit = null;
+        var condition: ?*const Expr = null;
+        var update: ?*const Expr = null;
+
+        if (self.peek() != .semicolon) {
+            if (self.peek() == .@"var" or self.peek() == .let or self.peek() == .@"const") {
+                const decl = try self.parseForDeclaration();
+                for_init = .{ .decl = decl };
+            } else {
+                const expr = try self.parseExpr(0);
+                for_init = .{ .expr = expr };
+            }
+        }
+
+        if (self.matchKeyword(.in)) {
+            const right = try self.parseExpr(0);
+            try self.expect(.rparen);
+            const body = try self.statementPointer();
+            return Stmt{
+                .loc = .{ .start = start, .end = body.loc.end },
+                .data = .{ .for_in = .{ .loc = .{ .start = start, .end = body.loc.end }, .left = for_init.?, .right = right, .body = body } },
+            };
+        }
+
+        if (self.matchKeyword(.of)) {
+            const right = try self.parseExpr(0);
+            try self.expect(.rparen);
+            const body = try self.statementPointer();
+            return Stmt{
+                .loc = .{ .start = start, .end = body.loc.end },
+                .data = .{ .for_of = .{ .loc = .{ .start = start, .end = body.loc.end }, .await_token = false, .left = for_init.?, .right = right, .body = body } },
+            };
+        }
+
+        try self.expect(.semicolon);
+        if (self.peek() != .semicolon and self.peek() != .rparen) {
+            condition = try self.parseExpr(0);
+        }
+        try self.expect(.semicolon);
+        if (self.peek() != .rparen) {
+            update = try self.parseExpr(0);
+        }
+        try self.expect(.rparen);
+        const body = try self.statementPointer();
+        return Stmt{
+            .loc = .{ .start = start, .end = body.loc.end },
+            .data = .{ .@"for" = .{ .loc = .{ .start = start, .end = body.loc.end }, .init = for_init, .condition = condition, .update = update, .body = body } },
+        };
+    }
+
+    fn parseForDeclaration(self: *@This()) ParseError!*const Decl {
+        const kind_tok = self.advanceTok();
+        var decls: [128]VarDeclarator = undefined;
+        var count: usize = 0;
+
+        while (true) {
+            const pat = try self.parseBindingPattern();
+            var decl_init: ?*const Expr = null;
+            if (self.match(.@"=")) {
+                decl_init = try self.parseExpr(0);
+            }
+            decls[count] = .{ .loc = pat.loc, .id = pat, .init = decl_init };
+            count += 1;
+            if (!self.match(.comma)) break;
+        }
+
+        const kind: VarKind = switch (kind_tok.kind) {
+            .@"var" => .@"var",
+            .let => .let,
+            .@"const" => .@"const",
+            else => return ParseError.UnexpectedToken,
+        };
+
+        return self.arena.declPtr(.{ .@"var" = .{ .loc = .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end }, .kind = kind, .decls = decls[0..count] } }, .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end });
+    }
+
+    fn parseContinue(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var label: ?[]const u8 = null;
+        if (self.peek() == .identifier and !self.isLineTerminatorBeforeNext()) {
+            const t = self.advanceTok();
+            label = self.tokenSlice(t);
+        }
+        self.semicolon();
+        return Stmt{ .loc = .{ .start = start, .end = start + 8 }, .data = .{ .@"continue" = .{ .loc = .{ .start = start, .end = start + 8 }, .label = label } } };
+    }
+
+    fn parseBreak(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var label: ?[]const u8 = null;
+        if (self.peek() == .identifier and !self.isLineTerminatorBeforeNext()) {
+            const t = self.advanceTok();
+            label = self.tokenSlice(t);
+        }
+        self.semicolon();
+        return Stmt{ .loc = .{ .start = start, .end = start + 5 }, .data = .{ .@"break" = .{ .loc = .{ .start = start, .end = start + 5 }, .label = label } } };
+    }
+
+    fn parseReturn(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var arg: ?*const Expr = null;
+        if (self.peek() != .semicolon and self.peek() != .rbrace and self.peek() != .eof and !self.isLineTerminatorBeforeNext()) {
+            arg = try self.parseExpr(0);
+        }
+        self.semicolon();
+        return Stmt{ .loc = .{ .start = start, .end = arg.?.loc.end }, .data = .{ .@"return" = .{ .loc = .{ .start = start, .end = if (arg) |a| a.loc.end else start + 6 }, .arg = arg } } };
+    }
+
+    fn parseSwitch(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        try self.expect(.lparen);
+        const discriminant = try self.parseExpr(0);
+        try self.expect(.rparen);
+        try self.expect(.lbrace);
+
+        var cases: [256]SwitchCase = undefined;
+        var case_count: usize = 0;
+
+        while (self.peek() == .case or self.peek() == .default) {
+            const case_start = self.tok().loc.start;
+            if (self.matchKeyword(.case)) {
+                const case_test = try self.parseExpr(0);
+                try self.expect(.@":");
+                var consequent: [128]Stmt = undefined;
+                var cons_count: usize = 0;
+                while (self.peek() != .case and self.peek() != .default and self.peek() != .rbrace and self.peek() != .eof) {
+                    const s = try self.parseStatementListItem();
+                    consequent[cons_count] = s;
+                    cons_count += 1;
+                }
+                cases[case_count] = .{ .loc = .{ .start = case_start, .end = self.tok().loc.start }, .condition = case_test, .consequent = consequent[0..cons_count] };
+                case_count += 1;
+            } else if (self.matchKeyword(.default)) {
+                try self.expect(.@":");
+                var consequent: [128]Stmt = undefined;
+                var cons_count: usize = 0;
+                while (self.peek() != .case and self.peek() != .default and self.peek() != .rbrace and self.peek() != .eof) {
+                    const s = try self.parseStatementListItem();
+                    consequent[cons_count] = s;
+                    cons_count += 1;
+                }
+                cases[case_count] = .{ .loc = .{ .start = case_start, .end = self.tok().loc.start }, .condition = null, .consequent = consequent[0..cons_count] };
+                case_count += 1;
+            }
+        }
+
+        const end_tok = try self.expectTok(.rbrace);
+        return Stmt{
+            .loc = .{ .start = start, .end = end_tok.loc.end },
+            .data = .{ .@"switch" = .{ .loc = .{ .start = start, .end = end_tok.loc.end }, .discriminant = discriminant, .cases = cases[0..case_count] } },
+        };
+    }
+
+    fn parseThrow(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        if (self.isLineTerminatorBeforeNext()) return ParseError.ExpectedExpression;
+        const arg = try self.parseExpr(0);
+        self.semicolon();
+        return Stmt{ .loc = .{ .start = start, .end = arg.loc.end }, .data = .{ .throw = .{ .loc = .{ .start = start, .end = arg.loc.end }, .arg = arg } } };
+    }
+
+    fn parseTry(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        const block = try self.parseBlockStmt();
+        var handler: ?CatchClause = null;
+        var finalizer: ?BlockStmt = null;
+
+        if (self.matchKeyword(.@"catch")) {
+            var param: ?Pat = null;
+            if (self.match(.lparen)) {
+                const pat = try self.parseBindingPattern();
+                param = pat;
+                try self.expect(.rparen);
+            }
+            const catch_body = try self.parseBlockStmt();
+            handler = .{ .loc = .{ .start = block.loc.start, .end = catch_body.loc.end }, .param = param, .body = catch_body };
+        }
+
+        if (self.matchKeyword(.finally)) {
+            const finally_body = try self.parseBlockStmt();
+            finalizer = finally_body;
+        }
+
+        const end = if (finalizer) |f| f.loc.end else if (handler) |h| h.loc.end else block.loc.end;
+        return Stmt{
+            .loc = .{ .start = start, .end = end },
+            .data = .{ .@"try" = .{ .loc = .{ .start = start, .end = end }, .block = block, .handler = handler, .finalizer = finalizer } },
+        };
+    }
+
+    fn parseWith(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        try self.expect(.lparen);
+        const obj = try self.parseExpr(0);
+        try self.expect(.rparen);
+        const body = try self.statementPointer();
+        return Stmt{
+            .loc = .{ .start = start, .end = body.loc.end },
+            .data = .{ .with = .{ .loc = .{ .start = start, .end = body.loc.end }, .obj = obj, .body = body } },
+        };
+    }
+
+    fn parseBlockStmt(self: *@This()) ParseError!BlockStmt {
+        const start = try self.expectTok(.lbrace);
+        var stmts: [1024]Stmt = undefined;
+        var count: usize = 0;
+
+        while (self.peek() != .rbrace and self.peek() != .eof) {
+            const s = try self.parseStatementListItem();
+            stmts[count] = s;
+            count += 1;
+            if (count >= stmts.len) return ParseError.TooManyTokens;
+        }
+
+        const end = try self.expectTok(.rbrace);
+        return .{ .loc = .{ .start = start.loc.start, .end = end.loc.end }, .body = stmts[0..count] };
+    }
+
+    fn parseVarStmt(self: *@This()) ParseError!Stmt {
+        const kind_tok = self.advanceTok();
+        var decls: [128]VarDeclarator = undefined;
+        var count: usize = 0;
+
+        while (true) {
+            const pat = try self.parseBindingPattern();
+            var decl_init: ?*const Expr = null;
+            if (self.match(.@"=")) {
+                decl_init = try self.parseExpr(0);
+            }
+            decls[count] = .{ .loc = pat.loc, .id = pat, .init = decl_init };
+            count += 1;
+            if (!self.match(.comma)) break;
+        }
+
+        self.semicolon();
+        const kind: VarKind = .@"var";
+        return Stmt{
+            .loc = .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end },
+            .data = .{ .variable = .{ .loc = .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end }, .kind = kind, .decls = decls[0..count] } },
+        };
+    }
+
+    fn parseLexicalDecl(self: *@This()) ParseError!Stmt {
+        const kind_tok = self.advanceTok();
+        var decls: [128]VarDeclarator = undefined;
+        var count: usize = 0;
+
+        while (true) {
+            const pat = try self.parseBindingPattern();
+            var decl_init: ?*const Expr = null;
+            if (kind_tok.kind == .@"const") {
+                if (!self.match(.@"=")) return ParseError.ExpectedToken;
+                decl_init = try self.parseExpr(0);
+            } else if (self.match(.@"=")) {
+                decl_init = try self.parseExpr(0);
+            }
+            decls[count] = .{ .loc = pat.loc, .id = pat, .init = decl_init };
+            count += 1;
+            if (!self.match(.comma)) break;
+        }
+
+        self.semicolon();
+        const kind: VarKind = switch (kind_tok.kind) {
+            .let => .let,
+            .@"const" => .@"const",
+            else => return ParseError.UnexpectedToken,
+        };
+        return Stmt{
+            .loc = .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end },
+            .data = .{ .lexical = .{ .loc = .{ .start = kind_tok.loc.start, .end = decls[count - 1].loc.end }, .kind = kind, .decls = decls[0..count] } },
+        };
+    }
+
+    fn parseUsingStmt(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var decls: [128]VarDeclarator = undefined;
+        var count: usize = 0;
+
+        while (true) {
+            const id_tok = try self.expectTok(.identifier);
+            const id = self.tokenSlice(id_tok);
+            var decl_init: ?*const Expr = null;
+            if (self.match(.@"=")) {
+                decl_init = try self.parseExpr(0);
+            }
+            decls[count] = .{ .loc = .{ .start = id_tok.loc.start, .end = if (decl_init) |e| e.loc.end else id_tok.loc.end }, .id = Pat{ .loc = .{ .start = id_tok.loc.start, .end = id_tok.loc.end }, .data = .{ .ident = id } }, .init = decl_init };
+            count += 1;
+            if (!self.match(.comma)) break;
+        }
+
+        self.semicolon();
+        return Stmt{
+            .loc = .{ .start = start, .end = decls[count - 1].loc.end },
+            .data = .{ .using = .{ .loc = .{ .start = start, .end = decls[count - 1].loc.end }, .decls = decls[0..count] } },
+        };
+    }
+
+    fn parseExpressionStatement(self: *@This()) ParseError!Stmt {
+        const expr = try self.parseExpr(0);
+        self.semicolon();
+        return Stmt{ .loc = expr.loc, .data = .{ .expr = .{ .loc = expr.loc, .expr = expr } } };
+    }
+
+    fn parseFunctionDecl(self: *@This(), fn_type_arg: FnType, mode: enum { stmt, expr }) ParseError!?Stmt {
+        const start = self.tok().loc.start;
+        var fn_type = fn_type_arg;
+
+        if (fn_type == .async) {
+            _ = self.advanceTok(); // async
+        } else if (fn_type == .async_generator) {
+            _ = self.advanceTok(); // async
+            _ = self.advanceTok(); // *
+        }
+
+        _ = self.advanceTok(); // function
+
+        if (fn_type == .normal and self.peek() == .@"*") {
+            self.advance();
+            fn_type = .generator;
+        }
+
+        var id: ?[]const u8 = null;
+        if (self.peek().isIdentifier()) {
+            const id_tok = self.advanceTok();
+            id = self.tokenSlice(id_tok);
+        }
+
+        const params = try self.parseParams();
+        const body = try self.parseFunctionBody();
+
+        const end = body.loc.end;
+
+        if (mode == .stmt) {
+            return Stmt{
+                .loc = .{ .start = start, .end = end },
+                .data = .{ .function = .{ .loc = .{ .start = start, .end = end }, .fn_type = fn_type, .id = id, .params = params, .body = body } },
+            };
+        }
+        return null;
+    }
+
+    fn parseFnExpr(self: *@This()) ParseError!*const Expr {
+        const start = self.advanceTok().loc.start;
+
+        var fn_type: FnType = .normal;
+        if (self.peek() == .@"*") {
+            fn_type = .generator;
+            self.advance();
+        }
+
+        var id: ?[]const u8 = null;
+        if (self.peek() == .identifier or self.peek().isKeywordButNotLet()) {
+            const id_tok = self.advanceTok();
+            id = self.tokenSlice(id_tok);
+        }
+
+        const params = try self.parseParams();
+        const body = try self.parseFunctionBody();
+
+        return self.arena.exprPtr(
+            .{ .func = .{ .loc = .{ .start = start, .end = body.loc.end }, .fn_type = fn_type, .id = id, .params = params, .body = body } },
+            .{ .start = start, .end = body.loc.end },
+        );
+    }
+
+    fn parseParams(self: *@This()) ParseError![]const Pat {
+        try self.expect(.lparen);
+        var params: [128]Pat = undefined;
+        var count: usize = 0;
+
+        if (self.peek() != .rparen) {
+            while (true) {
+                if (self.peek() == .@"...") {
+                    self.advance();
+                    const pat = try self.parseBindingPattern();
+                    params[count] = Pat{ .loc = pat.loc, .data = .{ .rest = .{ .loc = pat.loc, .arg = self.arena.patPtr(pat.data, pat.loc) } } };
+                    count += 1;
+                    break;
+                }
+                const pat = try self.parseBindingPattern();
+                if (self.match(.@"=")) {
+                    const expr = try self.parseExpr(0);
+                    params[count] = Pat{ .loc = .{ .start = pat.loc.start, .end = expr.loc.end }, .data = .{ .assign = .{ .loc = .{ .start = pat.loc.start, .end = expr.loc.end }, .left = self.arena.patPtr(pat.data, pat.loc), .right = expr } } };
+                } else {
+                    params[count] = pat;
+                }
+                count += 1;
+                if (!self.match(.comma)) break;
+                if (self.peek() == .@"...") {
+                    self.advance();
+                    const rest_pat = try self.parseBindingPattern();
+                    params[count] = Pat{ .loc = rest_pat.loc, .data = .{ .rest = .{ .loc = rest_pat.loc, .arg = self.arena.patPtr(rest_pat.data, rest_pat.loc) } } };
+                    count += 1;
+                    break;
+                }
+            }
+        }
+
+        try self.expect(.rparen);
+        return params[0..count];
+    }
+
+    fn parseFunctionBody(self: *@This()) ParseError!BlockStmt {
+        return self.parseBlockStmt();
+    }
+
+    fn parseClassDecl(self: *@This(), mode: enum { stmt, expr }) ParseError!?Stmt {
+        const start = self.advanceTok().loc.start;
+
+        var id: ?[]const u8 = null;
+        if (self.peek() == .identifier) {
+            const id_tok = self.advanceTok();
+            id = self.tokenSlice(id_tok);
+        }
+
+        var super_class: ?*const Expr = null;
+        if (self.matchKeyword(.extends)) {
+            super_class = try self.parseExpr(0);
+        }
+
+        try self.expect(.lbrace);
+        var elems: [128]ClassElem = undefined;
+        var elem_count: usize = 0;
+
+        while (self.peek() != .rbrace and self.peek() != .eof) {
+            const elem = try self.parseClassElement();
+            elems[elem_count] = elem;
+            elem_count += 1;
+            if (elem_count >= elems.len) return ParseError.TooManyTokens;
+        }
+
+        const end_tok = try self.expectTok(.rbrace);
+
+        if (mode == .stmt) {
+            return Stmt{
+                .loc = .{ .start = start, .end = end_tok.loc.end },
+                .data = .{ .class = .{ .loc = .{ .start = start, .end = end_tok.loc.end }, .id = id, .super_class = super_class, .body = elems[0..elem_count] } },
+            };
+        }
+        return null;
+    }
+
+    fn parseClassExpr(self: *@This()) ParseError!*const Expr {
+        const start = self.advanceTok().loc.start;
+
+        var id: ?[]const u8 = null;
+        if (self.peek() == .identifier) {
+            const id_tok = self.advanceTok();
+            id = self.tokenSlice(id_tok);
+        }
+
+        var super_class: ?*const Expr = null;
+        if (self.matchKeyword(.extends)) {
+            super_class = try self.parseExpr(0);
+        }
+
+        try self.expect(.lbrace);
+        var elems: [128]ClassElem = undefined;
+        var elem_count: usize = 0;
+
+        while (self.peek() != .rbrace and self.peek() != .eof) {
+            const elem = try self.parseClassElement();
+            elems[elem_count] = elem;
+            elem_count += 1;
+        }
+
+        const end_tok = try self.expectTok(.rbrace);
+        return self.arena.exprPtr(
+            .{ .class = .{ .loc = .{ .start = start, .end = end_tok.loc.end }, .id = id, .super_class = super_class, .body = elems[0..elem_count] } },
+            .{ .start = start, .end = end_tok.loc.end },
+        );
+    }
+
+    fn parseClassElement(self: *@This()) ParseError!ClassElem {
+        const start = self.tok().loc.start;
+        const is_static = self.matchKeyword(.static);
+
+        if (is_static and self.peek() == .lbrace) {
+            const body = try self.parseBlockStmt();
+            return ClassElem{ .static_block = body };
+        }
+
+        if (self.matchKeyword(.get)) {
+            const key = try self.parsePropKey();
+            try self.expect(.lparen);
+            try self.expect(.rparen);
+            const body = try self.parseFunctionBody();
+            if (is_static) return ClassElem{ .static_get = .{ .key = key, .body = body } };
+            return ClassElem{ .get = .{ .key = key, .body = body } };
+        }
+
+        if (self.matchKeyword(.set)) {
+            const key = try self.parsePropKey();
+            try self.expect(.lparen);
+            const param = try self.parseBindingPattern();
+            try self.expect(.rparen);
+            const body = try self.parseFunctionBody();
+            if (is_static) return ClassElem{ .static_set = .{ .key = key, .param = param, .body = body } };
+            return ClassElem{ .set = .{ .key = key, .param = param, .body = body } };
+        }
+
+        if (self.match(.@"*")) {
+            _ = try self.parsePropKey();
+            try self.expect(.lparen);
+            const params = try self.parseParams();
+            const body = try self.parseFunctionBody();
+            const fn_expr = FnExpr{ .loc = .{ .start = start, .end = body.loc.end }, .fn_type = .generator, .id = null, .params = params, .body = body };
+            if (is_static) return ClassElem{ .static_method = fn_expr };
+            return ClassElem{ .method = fn_expr };
+        }
+
+        const key = try self.parsePropKey();
+
+        if (self.peek() == .lparen) {
+            const params = try self.parseParams();
+            const body = try self.parseFunctionBody();
+            const fn_expr = FnExpr{ .loc = .{ .start = start, .end = body.loc.end }, .fn_type = .normal, .id = null, .params = params, .body = body };
+            if (is_static) return ClassElem{ .static_method = fn_expr };
+            return ClassElem{ .method = fn_expr };
+        }
+
+        var value: ?*const Expr = null;
+        if (self.match(.@"=")) {
+            value = try self.parseExpr(0);
+        }
+        if (self.peek() == .semicolon) self.advance();
+
+        const field = FieldDef{ .loc = .{ .start = start, .end = if (value) |v| v.loc.end else self.tok().loc.start }, .key = key, .value = value };
+        if (is_static) return ClassElem{ .static_field = field };
+        return ClassElem{ .field = field };
+    }
+
+    fn parseImport(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+        var specifiers: [32]ImportSpecifier = undefined;
+        var spec_count: usize = 0;
+
+        if (self.peek() != .string and self.peek() != .lparen) {
+            if (self.peek() == .identifier or self.peek().isKeyword()) {
+                const local_tok = self.advanceTok();
+                const local = self.tokenSlice(local_tok);
+                specifiers[spec_count] = .{ .default = local };
+                spec_count += 1;
+                if (self.match(.comma)) {}
+            }
+
+            if (self.match(.@"*")) {
+                try self.expect(.identifier); // as
+                const ns_tok = try self.expectTok(.identifier);
+                const ns = self.tokenSlice(ns_tok);
+                specifiers[spec_count] = .{ .namespace = ns };
+                spec_count += 1;
+            } else if (self.peek() == .lbrace) {
+                self.advance();
+                if (self.peek() != .rbrace) {
+                    while (true) {
+                        const imported_tok = try self.expectTok(.identifier);
+                        const imported = self.tokenSlice(imported_tok);
+                        var local = imported;
+                        if (self.match(.identifier)) {
+                            local = self.tokenSlice(self.tokens[self.pos - 1]);
+                        }
+                        specifiers[spec_count] = .{ .named = .{ .imported = imported, .local = local } };
+                        spec_count += 1;
+                        if (!self.match(.comma)) break;
+                    }
+                }
+                try self.expect(.rbrace);
+            }
+        }
+
+        var source: []const u8 = "";
+        var attrs: [8]ImportAttribute = undefined;
+        var attr_count: usize = 0;
+
+        if (self.matchKeyword(.from)) {
+            const str_tok = try self.expectTok(.string);
+            source = self.tokenSlice(str_tok);
+        } else if (self.peek() == .string) {
+            const str_tok = self.advanceTok();
+            source = self.tokenSlice(str_tok);
+        }
+
+        if (self.matchKeyword(.with)) {
+            try self.expect(.lbrace);
+            while (self.peek() != .rbrace and self.peek() != .eof) {
+                const key_tok = self.advanceTok();
+                const key = self.tokenSlice(key_tok);
+                try self.expect(.@":");
+                const val_tok = try self.expectTok(.string);
+                const val = self.tokenSlice(val_tok);
+                attrs[attr_count] = .{ .key = key, .value = val };
+                attr_count += 1;
+                _ = self.match(.comma);
+            }
+            try self.expect(.rbrace);
+        }
+
+        try self.expect(.semicolon);
+        return Stmt{
+            .loc = .{ .start = start, .end = self.tok().loc.start },
+            .data = .{ .import = .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .specifiers = specifiers[0..spec_count], .source = source, .attributes = attrs[0..attr_count] } },
+        };
+    }
+
+    fn parseExport(self: *@This()) ParseError!Stmt {
+        const start = self.advanceTok().loc.start;
+
+        if (self.matchKeyword(.default)) {
+            if (self.peek() == .function or self.peek() == .async or self.peek() == .class) {
+                const decl = try self.parseStatementListItem();
+                self.semicolon();
+                return Stmt{ .loc = .{ .start = start, .end = decl.loc.end }, .data = decl.data };
+            }
+            const expr = try self.parseExpr(0);
+            self.semicolon();
+            return Stmt{ .loc = .{ .start = start, .end = expr.loc.end }, .data = .{ .expr = .{ .loc = expr.loc, .expr = expr } } };
+        }
+
+        if (self.peek() == .@"*") {
+            self.advance();
+            try self.expect(.identifier); // from
+            const source_tok = try self.expectTok(.string);
+            _ = self.tokenSlice(source_tok);
+            try self.expect(.semicolon);
+            return Stmt{ .loc = .{ .start = start, .end = self.tok().loc.start }, .data = .{ .empty = {} } };
+        }
+
+        if (self.peek() == .lbrace) {
+            self.advance();
+            while (self.peek() != .rbrace and self.peek() != .eof) {
+                _ = self.advanceTok();
+                _ = self.match(.identifier); // as
+                if (!self.match(.comma)) break;
+            }
+            try self.expect(.rbrace);
+            if (self.matchKeyword(.from)) {
+                _ = self.advanceTok();
+            }
+            try self.expect(.semicolon);
+            return Stmt{ .loc = .{ .start = start, .end = self.tok().loc.start }, .data = .{ .empty = {} } };
+        }
+
+        const decl = try self.parseStatementListItem();
+        self.semicolon();
+        return decl;
+    }
+
+    fn parseExpr(self: *@This(), min_bp: u32) ParseError!*const Expr {
+        var left = try self.parsePrimaryExpr();
+
+        while (true) {
+            const cur_bp = self.bp(self.peek());
+            if (cur_bp <= min_bp) break;
+
+            switch (self.peek()) {
+                .@"=",
+                .@"+=",
+                .@"-=",
+                .@"*=",
+                .@"/=",
+                .@"%=",
+                .@"**=",
+                .@"<<=",
+                .@">>=",
+                .@">>>=",
+                .@"&=",
+                .@"|=",
+                .@"^=",
+                .@"&&=",
+                .@"||=",
+                .@"??=",
+                => {
+                    self.advance();
+                    const op = self.assignOpFromToken();
+                    const right = try self.parseExpr(BP.assign);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .assign = .{ .loc = loc, .op = op, .left = left, .right = right } }, loc);
+                },
+
+                .@"?" => {
+                    self.advance();
+                    const consequent = try self.parseExpr(0);
+                    try self.expect(.@":");
+                    const alternate = try self.parseExpr(BP.conditional);
+                    const loc: Loc = .{ .start = left.loc.start, .end = alternate.loc.end };
+                    left = self.arena.exprPtr(.{ .conditional = .{ .loc = loc, .condition = left, .consequent = consequent, .alternate = alternate } }, loc);
+                },
+
+                .@"??" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.coalesce);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"??", .left = left, .right = right } }, loc);
+                },
+
+                .@"||" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.log_or);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"||", .left = left, .right = right } }, loc);
+                },
+
+                .@"&&" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.log_and);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"&&", .left = left, .right = right } }, loc);
+                },
+
+                .@"|" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.bit_or);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"|", .left = left, .right = right } }, loc);
+                },
+
+                .@"^" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.bit_xor);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"^", .left = left, .right = right } }, loc);
+                },
+
+                .@"&" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.bit_and);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"&", .left = left, .right = right } }, loc);
+                },
+
+                .@"==" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.equality);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"==", .left = left, .right = right } }, loc);
+                },
+
+                .@"!=" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.equality);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"!=", .left = left, .right = right } }, loc);
+                },
+
+                .@"===" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.equality);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"===", .left = left, .right = right } }, loc);
+                },
+
+                .@"!==" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.equality);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"!==", .left = left, .right = right } }, loc);
+                },
+
+                .@"<" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"<", .left = left, .right = right } }, loc);
+                },
+
+                .@">" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@">", .left = left, .right = right } }, loc);
+                },
+
+                .@"<=" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"<=", .left = left, .right = right } }, loc);
+                },
+
+                .@">=" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@">=", .left = left, .right = right } }, loc);
+                },
+
+                .in => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .in, .left = left, .right = right } }, loc);
+                },
+
+                .instanceof => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.relational);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .instanceof, .left = left, .right = right } }, loc);
+                },
+
+                .@"<<" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.shift);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"<<", .left = left, .right = right } }, loc);
+                },
+
+                .@">>" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.shift);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@">>", .left = left, .right = right } }, loc);
+                },
+
+                .@">>>" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.shift);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@">>>", .left = left, .right = right } }, loc);
+                },
+
+                .@"+" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.additive);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"+", .left = left, .right = right } }, loc);
+                },
+
+                .@"-" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.additive);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"-", .left = left, .right = right } }, loc);
+                },
+
+                .@"*" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.multiplicative);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"*", .left = left, .right = right } }, loc);
+                },
+
+                .@"/" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.multiplicative);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"/", .left = left, .right = right } }, loc);
+                },
+
+                .@"%" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.multiplicative);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"%", .left = left, .right = right } }, loc);
+                },
+
+                .@"**" => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.exponentiation - 1);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    left = self.arena.exprPtr(.{ .binary = .{ .loc = loc, .op = .@"**", .left = left, .right = right } }, loc);
+                },
+
+                .lparen => {
+                    self.advance();
+                    var args: [256]Expr = undefined;
+                    var arg_count: usize = 0;
+
+                    if (self.peek() != .rparen) {
+                        while (true) {
+                            if (self.peek() == .@"...") {
+                                self.advance();
+                                const arg = try self.parseExpr(0);
+                                args[arg_count] = Expr{ .loc = arg.loc, .data = .{ .spread = .{ .loc = arg.loc, .arg = self.arena.exprPtr(arg.data, arg.loc) } } };
+                                arg_count += 1;
+                            } else {
+                                const arg = try self.parseExpr(0);
+                                args[arg_count] = arg.*;
+                                arg_count += 1;
+                            }
+                            if (!self.match(.comma)) break;
+                        }
+                    }
+
+                    try self.expect(.rparen);
+                    const loc: Loc = .{ .start = left.loc.start, .end = self.tok().loc.start };
+                    left = self.arena.exprPtr(.{ .call = .{ .loc = loc, .callee = left, .args = args[0..arg_count], .optional = false } }, loc);
+                },
+
+                .@"?." => {
+                    self.advance();
+                    if (self.peek() == .lparen) {
+                        self.advance();
+                        var args: [256]Expr = undefined;
+                        var arg_count: usize = 0;
+                        if (self.peek() != .rparen) {
+                            while (true) {
+                                const arg = try self.parseExpr(0);
+                                args[arg_count] = arg.*;
+                                arg_count += 1;
+                                if (!self.match(.comma)) break;
+                            }
+                        }
+                        try self.expect(.rparen);
+                        const loc: Loc = .{ .start = left.loc.start, .end = self.tok().loc.start };
+                        left = self.arena.exprPtr(.{ .call = .{ .loc = loc, .callee = left, .args = args[0..arg_count], .optional = true } }, loc);
+                    } else if (self.peek() == .lbracket) {
+                        self.advance();
+                        const expr = try self.parseExpr(0);
+                        try self.expect(.rbracket);
+                        const loc: Loc = .{ .start = left.loc.start, .end = self.tok().loc.start };
+                        left = self.arena.exprPtr(.{ .computed_member = .{ .loc = loc, .obj = left, .expr = expr } }, loc);
+                    } else if (self.peek() == .identifier or self.peek().isKeyword()) {
+                        const prop_tok = self.advanceTok();
+                        const prop = self.tokenSlice(prop_tok);
+                        const loc: Loc = .{ .start = left.loc.start, .end = prop_tok.loc.end };
+                        left = self.arena.exprPtr(.{ .member = .{ .loc = loc, .obj = left, .prop = .{ .ident = prop } } }, loc);
+                    } else if (self.peek() == .private_identifier) {
+                        const prop_tok = self.advanceTok();
+                        const prop = self.tokenSlice(prop_tok);
+                        const loc: Loc = .{ .start = left.loc.start, .end = prop_tok.loc.end };
+                        left = self.arena.exprPtr(.{ .member = .{ .loc = loc, .obj = left, .prop = .{ .private = prop } } }, loc);
+                    }
+                },
+
+                .lbracket => {
+                    self.advance();
+                    const expr = try self.parseExpr(0);
+                    try self.expect(.rbracket);
+                    const loc: Loc = .{ .start = left.loc.start, .end = self.tok().loc.start };
+                    left = self.arena.exprPtr(.{ .computed_member = .{ .loc = loc, .obj = left, .expr = expr } }, loc);
+                },
+
+                .@"." => {
+                    self.advance();
+                    if (self.peek() == .private_identifier) {
+                        const prop_tok = self.advanceTok();
+                        const prop = self.tokenSlice(prop_tok);
+                        const loc: Loc = .{ .start = left.loc.start, .end = prop_tok.loc.end };
+                        left = self.arena.exprPtr(.{ .member = .{ .loc = loc, .obj = left, .prop = .{ .private = prop } } }, loc);
+                    } else {
+                        const prop_tok = try self.expectTok(.identifier);
+                        const prop = self.tokenSlice(prop_tok);
+                        const loc: Loc = .{ .start = left.loc.start, .end = prop_tok.loc.end };
+                        left = self.arena.exprPtr(.{ .member = .{ .loc = loc, .obj = left, .prop = .{ .ident = prop } } }, loc);
+                    }
+                },
+
+                .template_head, .no_sub_template => {
+                    const template = try self.parseTemplateLit();
+                    const loc: Loc = .{ .start = left.loc.start, .end = template.loc.end };
+                    left = self.arena.exprPtr(.{ .tagged_template = .{ .loc = loc, .tag = left, .quasi = template } }, loc);
+                },
+
+                .@"++" => {
+                    if (!self.isLineTerminatorBeforeNext()) {
+                        self.advance();
+                        const loc: Loc = .{ .start = left.loc.start, .end = left.loc.end + 2 };
+                        left = self.arena.exprPtr(.{ .update = .{ .loc = loc, .op = .@"++", .arg = left, .prefix = false } }, loc);
+                    } else break;
+                },
+
+                .@"--" => {
+                    if (!self.isLineTerminatorBeforeNext()) {
+                        self.advance();
+                        const loc: Loc = .{ .start = left.loc.start, .end = left.loc.end + 2 };
+                        left = self.arena.exprPtr(.{ .update = .{ .loc = loc, .op = .@"--", .arg = left, .prefix = false } }, loc);
+                    } else break;
+                },
+
+                .comma => {
+                    self.advance();
+                    const right = try self.parseExpr(BP.comma);
+                    const loc: Loc = .{ .start = left.loc.start, .end = right.loc.end };
+                    var exprs: [2]Expr = .{ left.*, right.* };
+                    left = self.arena.exprPtr(.{ .sequence = .{ .loc = loc, .exprs = &exprs } }, loc);
+                },
+
+                else => break,
+            }
+        }
+
+        return left;
+    }
+
+    fn parsePrimaryExpr(self: *@This()) ParseError!*const Expr {
+        const start = self.tok().loc.start;
+
+        switch (self.peek()) {
+            .this => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .this = {} }, .{ .start = start, .end = t.loc.end });
+            },
+            .super => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .super = {} }, .{ .start = start, .end = t.loc.end });
+            },
+            .null => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .null = {} }, .{ .start = start, .end = t.loc.end });
+            },
+            .true => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .bool = true }, .{ .start = start, .end = t.loc.end });
+            },
+            .false => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .bool = false }, .{ .start = start, .end = t.loc.end });
+            },
+            .number => {
+                const t = self.advanceTok();
+                const val = std.fmt.parseFloat(f64, self.tokenSlice(t)) catch 0.0;
+                return self.arena.exprPtr(.{ .number = val }, .{ .start = start, .end = t.loc.end });
+            },
+            .string => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .string = self.tokenSlice(t) }, .{ .start = start, .end = t.loc.end });
+            },
+            .bigint => {
+                const t = self.advanceTok();
+                return self.arena.exprPtr(.{ .number = 0 }, .{ .start = start, .end = t.loc.end });
+            },
+            .regex => {
+                const t = self.advanceTok();
+                const slice = self.tokenSlice(t);
+                const slash_pos = std.mem.indexOfScalar(u8, slice[1..], '/') orelse 0;
+                const pattern = slice[1 .. slash_pos + 1];
+                const flags = slice[slash_pos + 2 ..];
+                return self.arena.exprPtr(
+                    .{ .regex = .{ .pattern = pattern, .flags = flags } },
+                    .{ .start = start, .end = t.loc.end },
+                );
+            },
+            .identifier => {
+                const t = self.advanceTok();
+                const name = self.tokenSlice(t);
+                return self.arena.exprPtr(.{ .identifier = name }, .{ .start = start, .end = t.loc.end });
+            },
+            .private_identifier => {
+                const t = self.advanceTok();
+                const name = self.tokenSlice(t);
+                return self.arena.exprPtr(.{ .private_ident = name }, .{ .start = start, .end = t.loc.end });
+            },
+            .lbrace => return self.parseObjLiteral(),
+            .lbracket => return self.parseArrayLiteral(),
+            .lparen => {
+                self.advance();
+                if (self.peek() == .rparen) {
+                    self.advance();
+                    if (self.peek() == .@"=>") {
+                        return self.parseArrowExpr(.{ .loc = .{ .start = start, .end = self.tok().loc.start }, .params = &.{} });
+                    }
+                    return self.arena.exprPtr(.{ .identifier = "" }, .{ .start = start, .end = self.tok().loc.start });
+                }
+                if (self.peek() == .@"...") {
+                    self.advance();
+                    const arg = try self.parseExpr(0);
+                    try self.expect(.rparen);
+                    if (self.peek() == .@"=>") {
+                        return self.parseArrowExpr(.{ .loc = .{ .start = start, .end = arg.loc.end }, .params = &.{} });
+                    }
+                    const loc: Loc = .{ .start = start, .end = self.tok().loc.start };
+                    return self.arena.exprPtr(.{ .spread = .{ .loc = loc, .arg = arg } }, loc);
+                }
+                const expr = try self.parseExpr(0);
+                if (self.peek() == .comma) {
+                    var params: [128]Pat = undefined;
+                    var count: usize = 0;
+                    params[count] = Pat{ .loc = expr.loc, .data = .{ .ident = expr.data.identifier } };
+                    count += 1;
+                    while (self.match(.comma)) {
+                        const p = try self.parseBindingPattern();
+                        params[count] = p;
+                        count += 1;
+                    }
+                    try self.expect(.rparen);
+                    if (self.peek() == .@"=>") {
+                        return self.parseArrowExpr(.{ .loc = .{ .start = start, .end = self.tok().loc.start }, .params = params[0..count] });
+                    }
+                    return self.arena.exprPtr(.{ .identifier = "" }, .{ .start = start, .end = self.tok().loc.start });
+                }
+                try self.expect(.rparen);
+                if (self.peek() == .@"=>") {
+                    const pat = Pat{ .loc = expr.loc, .data = .{ .ident = expr.data.identifier } };
+                    return self.parseArrowExpr(.{ .loc = .{ .start = start, .end = self.tok().loc.start }, .params = &.{pat} });
+                }
+                return self.arena.exprPtr(.{ .parenthesized = expr }, .{ .start = start, .end = self.tok().loc.start });
+            },
+            .function => return self.parseFnExpr(),
+            .class => return self.parseClassExpr(),
+            .async => {
+                self.advance();
+                if (self.peek() == .function) {
+                    return self.parseFnExpr();
+                }
+                const id_tok = try self.expectTok(.identifier);
+                const name = self.tokenSlice(id_tok);
+                if (self.peek() == .@"=>") {
+                    const pat = Pat{ .loc = .{ .start = start, .end = id_tok.loc.end }, .data = .{ .ident = name } };
+                    return self.parseArrowExpr(.{ .loc = .{ .start = start, .end = id_tok.loc.end }, .params = &.{pat} });
+                }
+                return self.arena.exprPtr(.{ .identifier = name }, .{ .start = start, .end = id_tok.loc.end });
+            },
+            .new => {
+                self.advance();
+                const callee = try self.parseExpr(BP.member);
+                var args: [256]Expr = undefined;
+                var arg_count: usize = 0;
+                if (self.peek() == .lparen) {
+                    self.advance();
+                    if (self.peek() != .rparen) {
+                        while (true) {
+                            const arg = try self.parseExpr(0);
+                            args[arg_count] = arg.*;
+                            arg_count += 1;
+                            if (!self.match(.comma)) break;
+                        }
+                    }
+                    try self.expect(.rparen);
+                }
+                const loc: Loc = .{ .start = start, .end = if (arg_count > 0) args[arg_count - 1].loc.end else callee.loc.end };
+                return self.arena.exprPtr(.{ .new = .{ .loc = loc, .callee = callee, .args = args[0..arg_count] } }, loc);
+            },
+            .delete, .typeof, .void, .@"!", .@"~", .@"+", .@"-" => {
+                const op = self.unaryOpFromToken();
+                self.advance();
+                const arg = try self.parseExpr(BP.unary);
+                const loc: Loc = .{ .start = start, .end = arg.loc.end };
+                return self.arena.exprPtr(.{ .unary = .{ .loc = loc, .op = op, .arg = arg, .prefix = true } }, loc);
+            },
+            .@"++" => {
+                self.advance();
+                const arg = try self.parseExpr(BP.update);
+                const loc: Loc = .{ .start = start, .end = arg.loc.end };
+                return self.arena.exprPtr(.{ .update = .{ .loc = loc, .op = .@"++", .arg = arg, .prefix = true } }, loc);
+            },
+            .@"--" => {
+                self.advance();
+                const arg = try self.parseExpr(BP.update);
+                const loc: Loc = .{ .start = start, .end = arg.loc.end };
+                return self.arena.exprPtr(.{ .update = .{ .loc = loc, .op = .@"--", .arg = arg, .prefix = true } }, loc);
+            },
+            .await => {
+                self.advance();
+                const arg = try self.parseExpr(BP.unary);
+                const loc: Loc = .{ .start = start, .end = arg.loc.end };
+                return self.arena.exprPtr(.{ .await = .{ .loc = loc, .arg = arg } }, loc);
+            },
+            .yield => {
+                self.advance();
+                var delegate = false;
+                var arg: ?*const Expr = null;
+                if (!self.isLineTerminatorBeforeNext()) {
+                    if (self.match(.@"*")) {
+                        delegate = true;
+                    }
+                    if (self.peek() != .rbrace and self.peek() != .rparen and self.peek() != .rbracket and self.peek() != .semicolon and self.peek() != .comma and self.peek() != .@":" and self.peek() != .eof) {
+                        arg = try self.parseExpr(0);
+                    }
+                }
+                const loc: Loc = .{ .start = start, .end = if (arg) |a| a.loc.end else start + 5 };
+                return self.arena.exprPtr(.{ .yield = .{ .loc = loc, .arg = arg, .delegate = delegate } }, loc);
+            },
+            .template_head, .no_sub_template => return self.arena.exprPtr(.{ .template = try self.parseTemplateLit() }, .{ .start = start, .end = self.tok().loc.start }),
+            .import => {
+                self.advance();
+                try self.expect(.lparen);
+                _ = try self.parseExpr(0);
+                try self.expect(.rparen);
+                return self.arena.exprPtr(.{ .identifier = "import" }, .{ .start = start, .end = self.tok().loc.start });
+            },
+            .@"#" => {
+                self.advance();
+                const id_tok = try self.expectTok(.identifier);
+                return self.arena.exprPtr(.{ .private_ident = self.tokenSlice(id_tok) }, .{ .start = start, .end = id_tok.loc.end });
+            },
+            else => {
+                if (self.peek().isIdentifier()) {
+                    const t = self.advanceTok();
+                    const name = self.tokenSlice(t);
+                    if (self.peek() == .@"=>") {
+                        const pat = Pat{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .data = .{ .ident = name } };
+                        return self.parseArrowExpr(.{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .params = &.{pat} });
+                    }
+                    return self.arena.exprPtr(.{ .identifier = name }, .{ .start = t.loc.start, .end = t.loc.end });
+                }
+                return ParseError.ExpectedExpression;
+            },
+        }
+    }
+
+    fn parseArrowExpr(self: *@This(), params_info: struct { loc: Loc, params: []const Pat }) ParseError!*const Expr {
+        try self.expect(.@"=>");
+        const async_token = false;
+
+        if (self.peek() == .lbrace) {
+            const body = try self.parseFunctionBody();
+            return self.arena.exprPtr(
+                .{ .arrow = .{ .loc = .{ .start = params_info.loc.start, .end = body.loc.end }, .async_token = async_token, .params = params_info.params, .body = .{ .block = body } } },
+                .{ .start = params_info.loc.start, .end = body.loc.end },
+            );
+        }
+
+        const expr = try self.parseExpr(0);
+        return self.arena.exprPtr(
+            .{ .arrow = .{ .loc = .{ .start = params_info.loc.start, .end = expr.loc.end }, .async_token = async_token, .params = params_info.params, .body = .{ .expr = expr } } },
+            .{ .start = params_info.loc.start, .end = expr.loc.end },
+        );
+    }
+
+    fn parseObjLiteral(self: *@This()) ParseError!*const Expr {
+        const start = self.advanceTok().loc.start;
+        var props: [128]Prop = undefined;
+        var count: usize = 0;
+
+        while (self.peek() != .rbrace and self.peek() != .eof) {
+            if (self.peek() == .@"...") {
+                self.advance();
+                const arg = try self.parseExpr(0);
+                props[count] = .{ .loc = arg.loc, .key = .{ .ident = "" }, .data = .{ .spread = .{ .loc = arg.loc, .arg = arg } } };
+                count += 1;
+            } else if (self.peek() == .identifier) {
+                const name_tok = self.tok();
+                const name = self.tokenSlice(name_tok);
+                self.advance();
+                if (self.peek() == .@":") {
+                    self.advance();
+                    const value = try self.parseExpr(0);
+                    props[count] = .{ .loc = .{ .start = name_tok.loc.start, .end = value.loc.end }, .key = .{ .ident = name }, .data = .{ .init = .{ .key = .{ .ident = name }, .value = value } } };
+                    count += 1;
+                } else if (self.peek() == .lparen) {
+                    const params = try self.parseParams();
+                    const body = try self.parseFunctionBody();
+                    props[count] = .{ .loc = .{ .start = name_tok.loc.start, .end = body.loc.end }, .key = .{ .ident = name }, .data = .{ .method = .{ .loc = .{ .start = name_tok.loc.start, .end = body.loc.end }, .fn_type = .normal, .id = null, .params = params, .body = body } } };
+                    count += 1;
+                } else if (self.peek() == .@"=") {
+                    self.advance();
+                    const value = try self.parseExpr(0);
+                    props[count] = .{ .loc = .{ .start = name_tok.loc.start, .end = value.loc.end }, .key = .{ .ident = name }, .data = .{ .init = .{ .key = .{ .ident = name }, .value = value } } };
+                    count += 1;
+                } else if (self.peek() == .comma or self.peek() == .rbrace) {
+                    props[count] = .{ .loc = .{ .start = name_tok.loc.start, .end = name_tok.loc.end }, .key = .{ .ident = name }, .data = .{ .shorthand = name } };
+                    count += 1;
+                }
+            } else if (self.peek() == .number or self.peek() == .string) {
+                const key = try self.parsePropKey();
+                try self.expect(.@":");
+                const value = try self.parseExpr(0);
+                props[count] = .{ .loc = .{ .start = start, .end = value.loc.end }, .key = key, .data = .{ .init = .{ .key = key, .value = value } } };
+                count += 1;
+            } else if (self.peek() == .lbracket) {
+                const key = try self.parsePropKey();
+                try self.expect(.@":");
+                const value = try self.parseExpr(0);
+                props[count] = .{ .loc = .{ .start = start, .end = value.loc.end }, .key = key, .data = .{ .init = .{ .key = key, .value = value } } };
+                count += 1;
+            } else if (self.matchKeyword(.get)) {
+                const key = try self.parsePropKey();
+                try self.expect(.lparen);
+                try self.expect(.rparen);
+                const body = try self.parseFunctionBody();
+                props[count] = .{ .loc = .{ .start = start, .end = body.loc.end }, .key = key, .data = .{ .get = .{ .key = key, .body = body } } };
+                count += 1;
+            } else if (self.matchKeyword(.set)) {
+                const key = try self.parsePropKey();
+                try self.expect(.lparen);
+                const param = try self.parseBindingPattern();
+                try self.expect(.rparen);
+                const body = try self.parseFunctionBody();
+                props[count] = .{ .loc = .{ .start = start, .end = body.loc.end }, .key = key, .data = .{ .set = .{ .key = key, .param = param, .body = body } } };
+                count += 1;
+            } else if (self.match(.@"*")) {
+                const key = try self.parsePropKey();
+                const params = try self.parseParams();
+                const body = try self.parseFunctionBody();
+                props[count] = .{ .loc = .{ .start = start, .end = body.loc.end }, .key = key, .data = .{ .method = .{ .loc = .{ .start = start, .end = body.loc.end }, .fn_type = .generator, .id = null, .params = params, .body = body } } };
+                count += 1;
+            } else {
+                break;
+            }
+
+            if (!self.match(.comma)) break;
+        }
+
+        try self.expect(.rbrace);
+        return self.arena.exprPtr(.{ .object = .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .props = props[0..count] } }, .{ .start = start, .end = self.tok().loc.start });
+    }
+
+    fn parseArrayLiteral(self: *@This()) ParseError!*const Expr {
+        const start = self.advanceTok().loc.start;
+        var elems: [256]?Expr = undefined;
+        var count: usize = 0;
+
+        while (self.peek() != .rbracket and self.peek() != .eof) {
+            if (self.match(.comma)) {
+                elems[count] = null;
+                count += 1;
+            } else if (self.peek() == .@"...") {
+                self.advance();
+                const arg = try self.parseExpr(0);
+                elems[count] = Expr{ .loc = arg.loc, .data = .{ .spread = .{ .loc = arg.loc, .arg = arg } } };
+                count += 1;
+                if (!self.match(.comma)) break;
+            } else {
+                const expr = try self.parseExpr(0);
+                elems[count] = expr.*;
+                count += 1;
+                if (!self.match(.comma)) break;
+            }
+        }
+
+        try self.expect(.rbracket);
+        return self.arena.exprPtr(.{ .array = .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .elems = elems[0..count] } }, .{ .start = start, .end = self.tok().loc.start });
+    }
+
+    fn parseTemplateLit(self: *@This()) ParseError!TemplateLit {
+        const start = self.tok().loc.start;
+        var quasis: [64]TemplateElem = undefined;
+        var exprs: [64]Expr = undefined;
+        var q_count: usize = 0;
+        var e_count: usize = 0;
+
+        while (true) {
+            switch (self.peek()) {
+                .no_sub_template => {
+                    const t = self.advanceTok();
+                    const slice = self.tokenSlice(t);
+                    quasis[q_count] = .{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .value = slice, .tail = true };
+                    q_count += 1;
+                    break;
+                },
+                .template_head => {
+                    const t = self.advanceTok();
+                    const slice = self.tokenSlice(t);
+                    quasis[q_count] = .{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .value = slice, .tail = false };
+                    q_count += 1;
+                    const expr = try self.parseExpr(0);
+                    exprs[e_count] = expr.*;
+                    e_count += 1;
+                    try self.expect(.rbrace);
+                },
+                .template_middle => {
+                    const t = self.advanceTok();
+                    const slice = self.tokenSlice(t);
+                    quasis[q_count] = .{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .value = slice, .tail = false };
+                    q_count += 1;
+                    const expr = try self.parseExpr(0);
+                    exprs[e_count] = expr.*;
+                    e_count += 1;
+                    try self.expect(.rbrace);
+                },
+                .template_tail => {
+                    const t = self.advanceTok();
+                    const slice = self.tokenSlice(t);
+                    quasis[q_count] = .{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .value = slice, .tail = true };
+                    q_count += 1;
+                    break;
+                },
+                else => break,
+            }
+        }
+
+        return .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .quasis = quasis[0..q_count], .exprs = exprs[0..e_count] };
+    }
+
+    fn parsePropKey(self: *@This()) ParseError!PropKey {
+        switch (self.peek()) {
+            .identifier, .let, .static, .get, .set, .async => {
+                const t = self.advanceTok();
+                return PropKey{ .ident = self.tokenSlice(t) };
+            },
+            .string => {
+                const t = self.advanceTok();
+                return PropKey{ .string = self.tokenSlice(t) };
+            },
+            .number => {
+                const t = self.advanceTok();
+                const val = std.fmt.parseFloat(f64, self.tokenSlice(t)) catch 0.0;
+                return PropKey{ .number = val };
+            },
+            .lbracket => {
+                self.advance();
+                const expr = try self.parseExpr(0);
+                try self.expect(.rbracket);
+                return PropKey{ .computed = expr };
+            },
+            .private_identifier => {
+                const t = self.advanceTok();
+                return PropKey{ .private = self.tokenSlice(t) };
+            },
+            else => return ParseError.ExpectedPropertyName,
+        }
+    }
+
+    fn parseBindingPattern(self: *@This()) ParseError!Pat {
+        const start = self.tok().loc.start;
+
+        switch (self.peek()) {
+            .identifier, .await, .yield => {
+                const t = self.advanceTok();
+                const name = self.tokenSlice(t);
+                return Pat{ .loc = .{ .start = start, .end = t.loc.end }, .data = .{ .ident = name } };
+            },
+            .lbrace => {
+                self.advance();
+                var props: [128]PatProp = undefined;
+                var count: usize = 0;
+                var rest: ?*const Pat = null;
+
+                while (self.peek() != .rbrace and self.peek() != .eof) {
+                    if (self.peek() == .@"...") {
+                        self.advance();
+                        const pat = try self.parseBindingPattern();
+                        rest = self.arena.patPtr(pat.data, pat.loc);
+                        break;
+                    }
+                    if (self.peek() == .identifier) {
+                        const name_tok = self.tok();
+                        const name = self.tokenSlice(name_tok);
+                        self.advance();
+                        if (self.peek() == .@":") {
+                            self.advance();
+                            const val_pat = try self.parseBindingPattern();
+                            props[count] = .{ .key_value = .{ .key = .{ .ident = name }, .value = self.arena.patPtr(val_pat.data, val_pat.loc) } };
+                            count += 1;
+                        } else {
+                            props[count] = .{ .shorthand = name };
+                            count += 1;
+                        }
+                    } else if (self.peek() == .lbracket) {
+                        const key = try self.parsePropKey();
+                        try self.expect(.@":");
+                        const val_pat = try self.parseBindingPattern();
+                        props[count] = .{ .key_value = .{ .key = key, .value = self.arena.patPtr(val_pat.data, val_pat.loc) } };
+                        count += 1;
+                    } else {
+                        break;
+                    }
+                    if (!self.match(.comma)) break;
+                }
+
+                try self.expect(.rbrace);
+                return Pat{ .loc = .{ .start = start, .end = self.tok().loc.start }, .data = .{ .object = .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .props = props[0..count], .rest = rest } } };
+            },
+            .lbracket => {
+                self.advance();
+                var elems: [128]?Pat = undefined;
+                var count: usize = 0;
+                var rest: ?*const Pat = null;
+
+                while (self.peek() != .rbracket and self.peek() != .eof) {
+                    if (self.match(.comma)) {
+                        elems[count] = null;
+                        count += 1;
+                    } else if (self.peek() == .@"...") {
+                        self.advance();
+                        const pat = try self.parseBindingPattern();
+                        rest = self.arena.patPtr(pat.data, pat.loc);
+                        break;
+                    } else {
+                        const pat = try self.parseBindingPattern();
+                        elems[count] = pat;
+                        count += 1;
+                        if (!self.match(.comma)) break;
+                    }
+                }
+
+                try self.expect(.rbracket);
+                return Pat{ .loc = .{ .start = start, .end = self.tok().loc.start }, .data = .{ .array = .{ .loc = .{ .start = start, .end = self.tok().loc.start }, .elems = elems[0..count], .rest = rest } } };
+            },
+            else => return ParseError.ExpectedParameterName,
+        }
+    }
+
+    fn bp(_: *@This(), kind: TokenType) u32 {
+        return switch (kind) {
+            .comma => BP.comma,
+            .@"=", .@"+=", .@"-=", .@"*=", .@"/=", .@"%=", .@"**=", .@"<<=", .@">>=", .@">>>=", .@"&=", .@"|=", .@"^=", .@"&&=", .@"||=", .@"??=" => BP.assign,
+            .@"?" => BP.conditional,
+            .@"??" => BP.coalesce,
+            .@"||" => BP.log_or,
+            .@"&&" => BP.log_and,
+            .@"|" => BP.bit_or,
+            .@"^" => BP.bit_xor,
+            .@"&" => BP.bit_and,
+            .@"==", .@"!=", .@"===", .@"!==" => BP.equality,
+            .@"<", .@">", .@"<=", .@">=", .in, .instanceof => BP.relational,
+            .@"<<", .@">>", .@">>>" => BP.shift,
+            .@"+", .@"-" => BP.additive,
+            .@"*", .@"/", .@"%" => BP.multiplicative,
+            .@"**" => BP.exponentiation,
+            .lparen => BP.call,
+            .lbracket, .@".", .@"?." => BP.member,
+            .@"++", .@"--" => BP.update,
+            .template_head, .no_sub_template => BP.member,
+            else => 0,
+        };
+    }
+
+    fn unaryOpFromToken(self: *@This()) UnaryOp {
+        return switch (self.tok().kind) {
+            .@"+" => .@"+",
+            .@"-" => .@"-",
+            .@"!" => .@"!",
+            .@"~" => .@"~",
+            .typeof => .typeof,
+            .void => .void,
+            .delete => .delete,
+            else => .@"+",
+        };
+    }
+
+    fn assignOpFromToken(self: *@This()) AssignOp {
+        return switch (self.tokens[self.pos - 1].kind) {
+            .@"=" => .@"=",
+            .@"+=" => .@"+=",
+            .@"-=" => .@"-=",
+            .@"*=" => .@"*=",
+            .@"/=" => .@"/=",
+            .@"%=" => .@"%=",
+            .@"**=" => .@"**=",
+            .@"<<=" => .@"<<=",
+            .@">>=" => .@">>=",
+            .@">>>=" => .@">>>=",
+            .@"&=" => .@"&=",
+            .@"|=" => .@"|=",
+            .@"^=" => .@"^=",
+            .@"&&=" => .@"&&=",
+            .@"||=" => .@"||=",
+            .@"??=" => .@"??=",
+            else => .@"=",
+        };
+    }
+
+    fn semicolon(self: *@This()) void {
+        if (self.peek() == .semicolon) {
+            self.advance();
+        }
+    }
+
+    fn statementPointer(self: *@This()) ParseError!*const Stmt {
+        const s = try self.parseStatement();
+        return self.arena.stmtPtr(s.data, s.loc);
+    }
+};
+
+pub const Node = union(enum) {
+    program: Program,
+
+    stmt: Stmt,
+    expr: Expr,
+    pat: Pat,
+
+    decl: Decl,
+    literal: Lit,
+    property: Prop,
+    template: TemplateLit,
+    spread: SpreadElem,
+    decorator: Decorator,
+
+    import_specifier: ImportSpecifier,
+    export_specifier: ExportSpecifier,
+    import_attr: ImportAttribute,
+    catch_clause: CatchClause,
+    switch_case: SwitchCase,
+};
+
+pub const Program = struct {
+    body: []const Stmt,
+    loc: Loc,
+
+    pub fn parse(comptime source: []const u8) ParseError!Program {
+        return comptime blk: {
+            var token_buf: [4096]Token = undefined;
+            const tokens = lex.Lexer.tokenizeBuf(source, &token_buf);
+            var arena: NodeArena = .{};
+            var parser = Parser.init(tokens, source, &arena);
+            break :blk try parser.parseProgram();
+        };
+    }
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        @setEvalBranchQuota(100000);
+        for (self.body, 0..) |stmt, i| {
+            if (i > 0) f.newline();
+            stmt.fmt(f);
+        }
+    }
+};
+
+pub const StmtType = union(enum) {
+    block: BlockStmt,
+    empty: void,
+    debugger: void,
+    expr: ExprStmt,
+    @"if": IfStmt,
+    @"while": WhileStmt,
+    do_while: DoWhileStmt,
+    @"for": ForStmt,
+    for_in: ForInStmt,
+    for_of: ForOfStmt,
+    @"continue": ContinueStmt,
+    @"break": BreakStmt,
+    @"return": ReturnStmt,
+    @"switch": SwitchStmt,
+    throw: ThrowStmt,
+    @"try": TryStmt,
+    labelled: LabelledStmt,
+    with: WithStmt,
+    variable: VarStmt,
+    lexical: LexicalDecl,
+    function: FnDecl,
+    class: ClassDecl,
+    using: UsingStmt,
+    import: ImportDecl,
+    @"export": ExportDecl,
+};
+
+pub const Stmt = struct {
+    loc: Loc,
+    data: StmtType,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        switch (self.data) {
+            .block => |b| b.fmt(f),
+            .empty => f.writeChar(';'),
+            .debugger => f.write("debugger;"),
+            .expr => |e| {
+                e.expr.*.fmt(f);
+                f.writeChar(';');
+            },
+            .@"if" => |s| s.fmt(f),
+            .@"while" => |w| w.fmt(f),
+            .do_while => |d| d.fmt(f),
+            .@"for" => |fo| fo.fmt(f),
+            .for_in => |fi| fi.fmt(f),
+            .for_of => |fo| fo.fmt(f),
+            .@"continue" => |c| {
+                f.write("continue");
+                if (c.label) |l| {
+                    f.writeChar(' ');
+                    f.write(l);
+                }
+                f.writeChar(';');
+            },
+            .@"break" => |b| {
+                f.write("break");
+                if (b.label) |l| {
+                    f.writeChar(' ');
+                    f.write(l);
+                }
+                f.writeChar(';');
+            },
+            .@"return" => |r| {
+                f.write("return");
+                if (r.arg) |a| {
+                    f.writeChar(' ');
+                    a.*.fmt(f);
+                }
+                f.writeChar(';');
+            },
+            .@"switch" => |s| s.fmt(f),
+            .throw => |t| {
+                f.write("throw ");
+                t.arg.*.fmt(f);
+                f.writeChar(';');
+            },
+            .@"try" => |t| t.fmt(f),
+            .labelled => |l| {
+                f.write(l.label);
+                f.write(": ");
+                l.body.*.fmt(f);
+            },
+            .with => |w| {
+                f.write("with (");
+                w.obj.*.fmt(f);
+                f.write(") ");
+                w.body.*.fmt(f);
+            },
+            .variable => |v| v.fmt(f),
+            .lexical => |l| l.fmt(f),
+            .using => |u| {
+                f.write("using ");
+                for (u.decls, 0..) |d, i| {
+                    if (i > 0) f.write(", ");
+                    d.fmt(f);
+                }
+                f.writeChar(';');
+            },
+            .import => |i| i.fmt(f),
+            .@"export" => |e| e.fmt(f),
+            .class => |c| c.fmt(f),
+            .function => |d| d.fmt(f),
+        }
+    }
+};
+
+pub const ExprType = union(enum) {
+    identifier: []const u8,
+    this: void,
+    super: void,
+    null: void,
+    bool: bool,
+    number: f64,
+    string: []const u8,
+    regex: Regex,
+    array: ArrayExpr,
+    object: ObjectExpr,
+    func: FnExpr,
+    arrow: ArrowFn,
+    class: ClassExpr,
+    template: TemplateLit,
+    tagged_template: TaggedTemplate,
+    member: MemberExpr,
+    computed_member: ComputedMember,
+    call: CallExpr,
+    new: NewExpr,
+    chain: ChainExpr,
+    unary: UnaryExpr,
+    binary: BinaryExpr,
+    update: UpdateExpr,
+    conditional: IfExpr,
+    assign: AssignExpr,
+    sequence: SeqExpr,
+    spread: SpreadElem,
+    yield: YieldExpr,
+    await: AwaitExpr,
+    meta_prop: MetaProp,
+    parenthesized: *const Expr,
+    private_ident: []const u8,
+};
+
+pub const Expr = struct {
+    loc: Loc,
+    data: ExprType,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        switch (self.data) {
+            .identifier => |name| f.write(name),
+            .this => f.write("this"),
+            .super => f.write("super"),
+            .null => f.write("null"),
+            .bool => |b| f.write(if (b) "true" else "false"),
+            .number => |n| {
+                var buf: [64]u8 = undefined;
+                f.write(std.fmt.bufPrint(&buf, "{d}", .{n}) catch "0");
+            },
+            .string => |s| {
+                f.writeChar('"');
+                f.write(s);
+                f.writeChar('"');
+            },
+            .regex => |r| {
+                f.writeChar('/');
+                f.write(r.pattern);
+                f.writeChar('/');
+                f.write(r.flags);
+            },
+            .array => |a| a.fmt(f),
+            .object => |o| o.fmt(f),
+            .func => |fn_expr| fn_expr.fmt(f),
+            .arrow => |arrow| arrow.fmt(f),
+            .class => |c| c.fmt(f),
+            .template => |t| t.fmt(f),
+            .tagged_template => |tt| tt.fmt(f),
+            .member => |m| m.fmt(f),
+            .computed_member => |cm| cm.fmt(f),
+            .call => |call| call.fmt(f),
+            .new => |n| {
+                f.write("new ");
+                n.callee.*.fmt(f);
+                f.writeChar('(');
+                for (n.args, 0..) |a, i| {
+                    if (i > 0) f.write(", ");
+                    a.fmt(f);
+                }
+                f.writeChar(')');
+            },
+            .chain => |c| c.expr.*.fmt(f),
+            .unary => |u| {
+                if (u.prefix) {
+                    f.write(@tagName(u.op));
+                    u.arg.*.fmt(f);
+                } else {
+                    u.arg.*.fmt(f);
+                    f.write(@tagName(u.op));
+                }
+            },
+            .binary => |b| {
+                f.writeChar('(');
+                b.left.*.fmt(f);
+                f.writeChar(' ');
+                f.write(@tagName(b.op));
+                f.writeChar(' ');
+                b.right.*.fmt(f);
+                f.writeChar(')');
+            },
+            .update => |u| {
+                const s = if (u.op == .@"++") "++" else "--";
+                if (u.prefix) {
+                    f.write(s);
+                    u.arg.*.fmt(f);
+                } else {
+                    u.arg.*.fmt(f);
+                    f.write(s);
+                }
+            },
+            .conditional => |c| {
+                c.condition.*.fmt(f);
+                f.write(" ? ");
+                c.consequent.*.fmt(f);
+                f.write(" : ");
+                c.alternate.*.fmt(f);
+            },
+            .assign => |a| {
+                a.left.*.fmt(f);
+                f.writeChar(' ');
+                f.write(@tagName(a.op));
+                f.writeChar(' ');
+                a.right.*.fmt(f);
+            },
+            .sequence => |s| {
+                for (s.exprs, 0..) |e, i| {
+                    if (i > 0) f.write(", ");
+                    e.fmt(f);
+                }
+            },
+            .spread => |s| {
+                f.write("...");
+                s.arg.*.fmt(f);
+            },
+            .yield => |y| {
+                f.write("yield");
+                if (y.delegate) f.write("*");
+                if (y.arg) |a| {
+                    f.writeChar(' ');
+                    a.*.fmt(f);
+                }
+            },
+            .await => |a| {
+                f.write("await ");
+                a.arg.*.fmt(f);
+            },
+            .meta_prop => |m| {
+                f.write(m.meta);
+                f.writeChar('.');
+                f.write(m.prop);
+            },
+            .parenthesized => |p| {
+                f.writeChar('(');
+                p.*.fmt(f);
+                f.writeChar(')');
+            },
+            .private_ident => |name| f.write(name),
+        }
+    }
+};
+
+pub const PatType = union(enum) {
+    ident: []const u8,
+    object: ObjectPat,
+    array: ArrayPat,
+    assign: AssignPat,
+    rest: RestPat,
+};
+
+pub const Pat = struct {
+    loc: Loc,
+    data: PatType,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        switch (self.data) {
+            .ident => |name| f.write(name),
+            .object => |o| o.fmt(f),
+            .array => |a| a.fmt(f),
+            .assign => |a| {
+                a.left.*.fmt(f);
+                f.write(" = ");
+                a.right.*.fmt(f);
+            },
+            .rest => |r| {
+                f.write("...");
+                r.arg.*.fmt(f);
+            },
+        }
+    }
+};
+
+pub const DeclType = union(enum) {
+    @"fn": FnDecl,
+    class: ClassDecl,
+    @"var": VarDecl,
+    using: UsingDecl,
+    import: ImportDecl,
+    @"export": ExportDecl,
+    export_default: ExportDefault,
+};
+
+pub const Decl = struct {
+    loc: Loc,
+    data: DeclType,
+};
+
+pub const LitType = union(enum) {
+    null: void,
+    bool: bool,
+    number: f64,
+    string: []const u8,
+    regex: Regex,
+    bigint: []const u8,
+};
+
+pub const Lit = struct {
+    loc: Loc,
+    data: LitType,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        switch (self.data) {
+            .null => f.write("null"),
+            .bool => |b| f.write(if (b) "true" else "false"),
+            .number => |n| {
+                var buf: [64]u8 = undefined;
+                f.write(std.fmt.bufPrint(&buf, "{d}", .{n}) catch "0");
+            },
+            .string => |s| {
+                f.writeChar('"');
+                f.write(s);
+                f.writeChar('"');
+            },
+            .regex => |r| {
+                f.writeChar('/');
+                f.write(r.pattern);
+                f.writeChar('/');
+                f.write(r.flags);
+            },
+            .bigint => |s| {
+                f.write(s);
+                f.writeChar('n');
+            },
+        }
+    }
+};
+
+pub const Regex = struct {
+    pattern: []const u8,
+    flags: []const u8,
+};
+
+pub const PropType = union(enum) {
+    init: PropInit,
+    get: PropGet,
+    set: PropSet,
+    shorthand: []const u8,
+    spread: SpreadElem,
+    method: FnExpr,
+};
+
+pub const Prop = struct {
+    loc: Loc,
+    key: PropKey,
+    data: PropType,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        switch (self.data) {
+            .init => |p_init| {
+                self.key.fmt(f);
+                f.write(": ");
+                p_init.value.*.fmt(f);
+            },
+            .get => |g| g.fmt(f),
+            .set => |s| s.fmt(f),
+            .shorthand => |name| f.write(name),
+            .spread => |sp| {
+                f.write("...");
+                sp.arg.*.fmt(f);
+            },
+            .method => |m| m.fmt(f),
+        }
+    }
+};
+
+pub const PropKey = union(enum) {
+    ident: []const u8,
+    string: []const u8,
+    number: f64,
+    computed: *const Expr,
+    private: []const u8,
+};
+
+pub const PropInit = struct {
+    key: PropKey,
+    value: *const Expr,
+};
+
+pub const PropGet = struct {
+    key: PropKey,
+    body: BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("get ");
+        self.key.fmt(f);
+        f.write("() ");
+        self.body.fmt(f);
+    }
+};
+
+pub const PropSet = struct {
+    key: PropKey,
+    param: Pat,
+    body: BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("set ");
+        self.key.fmt(f);
+        f.writeChar('(');
+        self.param.fmt(f);
+        f.write(") ");
+        self.body.fmt(f);
+    }
+};
+
+pub const SpreadElem = struct {
+    loc: Loc,
+    arg: *const Expr,
+};
+
+pub const BlockStmt = struct {
+    loc: Loc,
+    body: []const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('{');
+        if (self.body.len > 0) {
+            f.newline();
+            f.indent_level += 1;
+            for (self.body) |s| {
+                f.writeIndent();
+                s.fmt(f);
+                f.newline();
+            }
+            f.indent_level -= 1;
+            f.writeIndent();
+        }
+        f.writeChar('}');
+    }
+};
+
+pub const ExprStmt = struct {
+    loc: Loc,
+    expr: *const Expr,
+};
+
+pub const IfStmt = struct {
+    loc: Loc,
+    condition: *const Expr,
+    consequent: *const Stmt,
+    alternate: ?*const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("if (");
+        self.condition.*.fmt(f);
+        f.write(") ");
+        self.consequent.*.fmt(f);
+        if (self.alternate) |alt| {
+            f.write(" else ");
+            alt.*.fmt(f);
+        }
+    }
+};
+
+pub const WhileStmt = struct {
+    loc: Loc,
+    condition: *const Expr,
+    body: *const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("while (");
+        self.condition.*.fmt(f);
+        f.write(") ");
+        self.body.*.fmt(f);
+    }
+};
+
+pub const DoWhileStmt = struct {
+    loc: Loc,
+    body: *const Stmt,
+    condition: *const Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("do ");
+        self.body.*.fmt(f);
+        f.write(" while (");
+        self.condition.*.fmt(f);
+        f.write(");");
+    }
+};
+
+pub const ForInit = union(enum) {
+    expr: *const Expr,
+    decl: *const Decl,
+};
+
+pub const ForStmt = struct {
+    loc: Loc,
+    init: ?ForInit,
+    condition: ?*const Expr,
+    update: ?*const Expr,
+    body: *const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("for (");
+        if (self.init) |init| {
+            switch (init) {
+                .expr => |e| e.*.fmt(f),
+                .decl => |d| d.*.fmt(f),
+            }
+        }
+        f.writeChar(';');
+        if (self.condition) |c| {
+            f.writeChar(' ');
+            c.*.fmt(f);
+        }
+        f.writeChar(';');
+        if (self.update) |u| {
+            f.writeChar(' ');
+            u.*.fmt(f);
+        }
+        f.write(") ");
+        self.body.*.fmt(f);
+    }
+};
+
+pub const ForInStmt = struct {
+    loc: Loc,
+    left: ForInit,
+    right: *const Expr,
+    body: *const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("for (");
+        switch (self.left) {
+            .expr => |e| e.*.fmt(f),
+            .decl => |d| d.*.fmt(f),
+        }
+        f.write(" in ");
+        self.right.*.fmt(f);
+        f.write(") ");
+        self.body.*.fmt(f);
+    }
+};
+
+pub const ForOfStmt = struct {
+    loc: Loc,
+    await_token: bool,
+    left: ForInit,
+    right: *const Expr,
+    body: *const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("for");
+        if (self.await_token) f.write(" await");
+        f.write(" (");
+        switch (self.left) {
+            .expr => |e| e.*.fmt(f),
+            .decl => |d| d.*.fmt(f),
+        }
+        f.write(" of ");
+        self.right.*.fmt(f);
+        f.write(") ");
+        self.body.*.fmt(f);
+    }
+};
+
+pub const ContinueStmt = struct {
+    loc: Loc,
+    label: ?[]const u8,
+};
+
+pub const BreakStmt = struct {
+    loc: Loc,
+    label: ?[]const u8,
+};
+
+pub const ReturnStmt = struct {
+    loc: Loc,
+    arg: ?*const Expr,
+};
+
+pub const SwitchStmt = struct {
+    loc: Loc,
+    discriminant: *const Expr,
+    cases: []const SwitchCase,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("switch (");
+        self.discriminant.*.fmt(f);
+        f.write(") {");
+        f.newline();
+        f.indent_level += 1;
+        for (self.cases) |c| {
+            f.writeIndent();
+            c.fmt(f);
+            f.newline();
+        }
+        f.indent_level -= 1;
+        f.writeIndent();
+        f.writeChar('}');
+    }
+};
+
+pub const SwitchCase = struct {
+    loc: Loc,
+    condition: ?*const Expr,
+    consequent: []const Stmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        if (self.condition) |c| {
+            f.write("case ");
+            c.*.fmt(f);
+        } else {
+            f.write("default");
+        }
+        f.writeChar(':');
+        for (self.consequent) |s| {
+            f.writeChar(' ');
+            s.fmt(f);
+        }
+    }
+};
+
+pub const ThrowStmt = struct {
+    loc: Loc,
+    arg: *const Expr,
+};
+
+pub const TryStmt = struct {
+    loc: Loc,
+    block: BlockStmt,
+    handler: ?CatchClause,
+    finalizer: ?BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("try ");
+        self.block.fmt(f);
+        if (self.handler) |h| {
+            f.writeChar(' ');
+            h.fmt(f);
+        }
+        if (self.finalizer) |fin| {
+            f.write(" finally ");
+            fin.fmt(f);
+        }
+    }
+};
+
+pub const CatchClause = struct {
+    loc: Loc,
+    param: ?Pat,
+    body: BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("catch");
+        if (self.param) |p| {
+            f.write(" (");
+            p.fmt(f);
+            f.write(") ");
+        } else {
+            f.writeChar(' ');
+        }
+        self.body.fmt(f);
+    }
+};
+
+pub const LabelledStmt = struct {
+    loc: Loc,
+    label: []const u8,
+    body: *const Stmt,
+};
+
+pub const WithStmt = struct {
+    loc: Loc,
+    obj: *const Expr,
+    body: *const Stmt,
+};
+
+pub const VarStmt = struct {
+    loc: Loc,
+    kind: VarKind,
+    decls: []const VarDeclarator,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write(@tagName(self.kind));
+        f.writeChar(' ');
+        for (self.decls, 0..) |d, i| {
+            if (i > 0) f.write(", ");
+            d.fmt(f);
+        }
+        f.writeChar(';');
+    }
+};
+
+pub const UsingStmt = struct {
+    loc: Loc,
+    decls: []const VarDeclarator,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("using ");
+        for (self.decls, 0..) |d, i| {
+            if (i > 0) f.write(", ");
+            d.fmt(f);
+        }
+    }
+};
+
+pub const VarKind = enum {
+    @"var",
+    let,
+    @"const",
+};
+
+pub const VarDecl = struct {
+    loc: Loc,
+    kind: VarKind,
+    decls: []const VarDeclarator,
+};
+
+pub const LexicalDecl = struct {
+    loc: Loc,
+    kind: VarKind,
+    decls: []const VarDeclarator,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write(@tagName(self.kind));
+        f.writeChar(' ');
+        for (self.decls, 0..) |d, i| {
+            if (i > 0) f.write(", ");
+            d.fmt(f);
+        }
+        f.writeChar(';');
+    }
+};
+
+pub const UsingDecl = struct {
+    loc: Loc,
+    is_await: bool,
+    decls: []const VarDeclarator,
+};
+
+pub const VarDeclarator = struct {
+    loc: Loc,
+    id: Pat,
+    init: ?*const Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        self.id.fmt(f);
+        if (self.init) |init| {
+            f.write(" = ");
+            init.*.fmt(f);
+        }
+    }
+};
+
+pub const ObjectPat = struct {
+    loc: Loc,
+    props: []const PatProp,
+    rest: ?*const Pat,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('{');
+        var first = true;
+        for (self.props) |prop| {
+            if (!first) f.write(", ");
+            first = false;
+            switch (prop) {
+                .key_value => |kv| {
+                    kv.key.fmt(f);
+                    f.write(": ");
+                    kv.value.*.fmt(f);
+                },
+                .shorthand => |name| f.write(name),
+                .rest => |r| {
+                    f.write("...");
+                    r.*.fmt(f);
+                },
+            }
+        }
+        if (self.rest) |rest| {
+            if (!first) f.write(", ");
+            f.write("...");
+            rest.*.fmt(f);
+        }
+        f.writeChar('}');
+    }
+};
+
+pub const PatProp = union(enum) {
+    key_value: struct {
+        key: PropKey,
+        value: *const Pat,
+    },
+    shorthand: []const u8,
+    rest: *const Pat,
+};
+
+pub const ArrayPat = struct {
+    loc: Loc,
+    elems: []const ?Pat,
+    rest: ?*const Pat,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('[');
+        for (self.elems, 0..) |elem, i| {
+            if (i > 0) f.write(", ");
+            if (elem) |pat| pat.fmt(f);
+        }
+        if (self.rest) |rest| {
+            if (self.elems.len > 0) f.write(", ");
+            f.write("...");
+            rest.*.fmt(f);
+        }
+        f.writeChar(']');
+    }
+};
+
+pub const AssignPat = struct {
+    loc: Loc,
+    left: *const Pat,
+    right: *const Expr,
+};
+
+pub const RestPat = struct {
+    loc: Loc,
+    arg: *const Pat,
+};
+
+pub const FnType = union(enum) {
+    normal: void,
+    generator: void,
+    async: void,
+    async_generator: void,
+};
+
+pub const FnDecl = struct {
+    loc: Loc,
+    fn_type: FnType,
+    id: ?[]const u8,
+    params: []const Pat,
+    body: BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("function");
+        if (self.fn_type == .generator or self.fn_type == .async_generator) {
+            f.write("*");
+        }
+        if (self.fn_type == .async or self.fn_type == .async_generator) {
+            f.write(" async");
+        }
+        if (self.id) |id| {
+            f.writeChar(' ');
+            f.write(id);
+        }
+        f.writeChar('(');
+        for (self.params, 0..) |p, i| {
+            if (i > 0) f.write(", ");
+            p.fmt(f);
+        }
+        f.write(") ");
+        self.body.fmt(f);
+    }
+};
+
+pub const FnExpr = struct {
+    loc: Loc,
+    fn_type: FnType,
+    id: ?[]const u8,
+    params: []const Pat,
+    body: BlockStmt,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("function");
+        if (self.fn_type == .generator or self.fn_type == .async_generator) {
+            f.write("*");
+        }
+        if (self.fn_type == .async or self.fn_type == .async_generator) {
+            f.write(" async");
+        }
+        if (self.id) |id| {
+            f.writeChar(' ');
+            f.write(id);
+        }
+        f.writeChar('(');
+        for (self.params, 0..) |p, i| {
+            if (i > 0) f.write(", ");
+            p.fmt(f);
+        }
+        f.write(") ");
+        self.body.fmt(f);
+    }
+};
+
+pub const ArrowFn = struct {
+    loc: Loc,
+    async_token: bool,
+    params: []const Pat,
+    body: union(enum) {
+        block: BlockStmt,
+        expr: *const Expr,
+    },
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        if (self.async_token) f.write("async ");
+        f.writeChar('(');
+        for (self.params, 0..) |p, i| {
+            if (i > 0) f.write(", ");
+            p.fmt(f);
+        }
+        f.write(") => ");
+        switch (self.body) {
+            .block => |b| b.fmt(f),
+            .expr => |e| e.*.fmt(f),
+        }
+    }
+};
+
+pub const ClassDecl = struct {
+    loc: Loc,
+    id: ?[]const u8,
+    super_class: ?*const Expr,
+    body: []const ClassElem,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("class");
+        if (self.id) |id| {
+            f.writeChar(' ');
+            f.write(id);
+        }
+        if (self.super_class) |sc| {
+            f.write(" extends ");
+            sc.*.fmt(f);
+        }
+        f.write(" {");
+        f.newline();
+        f.indent_level += 1;
+        for (self.body) |elem| {
+            f.writeIndent();
+            elem.fmt(f);
+            f.newline();
+        }
+        f.indent_level -= 1;
+        f.writeIndent();
+        f.writeChar('}');
+    }
+};
+
+pub const ClassExpr = struct {
+    loc: Loc,
+    id: ?[]const u8,
+    super_class: ?*const Expr,
+    body: []const ClassElem,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("class");
+        if (self.id) |id| {
+            f.writeChar(' ');
+            f.write(id);
+        }
+        if (self.super_class) |sc| {
+            f.write(" extends ");
+            sc.*.fmt(f);
+        }
+        f.write(" {");
+        f.newline();
+        f.indent_level += 1;
+        for (self.body) |elem| {
+            f.writeIndent();
+            elem.fmt(f);
+            f.newline();
+        }
+        f.indent_level -= 1;
+        f.writeIndent();
+        f.writeChar('}');
+    }
+};
+
+pub const ClassElem = union(enum) {
+    method: FnExpr,
+    get: PropGet,
+    set: PropSet,
+    field: FieldDef,
+    static_block: BlockStmt,
+    static_method: FnExpr,
+    static_get: PropGet,
+    static_set: PropSet,
+    static_field: FieldDef,
+};
+
+pub const FieldDef = struct {
+    loc: Loc,
+    key: PropKey,
+    value: ?*const Expr,
+};
+
+pub const ImportDecl = struct {
+    loc: Loc,
+    specifiers: []const ImportSpecifier,
+    source: []const u8,
+    attributes: []const ImportAttribute,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("import ");
+        if (self.specifiers.len > 0) {
+            for (self.specifiers, 0..) |spec, j| {
+                if (j > 0) f.write(", ");
+                spec.fmt(f);
+            }
+            f.write(" from ");
+        }
+        f.writeChar('"');
+        f.write(self.source);
+        f.writeChar('"');
+        for (self.attributes) |a| {
+            f.write(" /* ");
+            a.fmt(f);
+            f.write(" */");
+        }
+        f.writeChar(';');
+    }
+};
+
+pub const ImportSpecifier = union(enum) {
+    default: []const u8,
+    namespace: []const u8,
+    named: struct { imported: []const u8, local: []const u8 },
+};
+
+pub const ImportAttribute = struct {
+    key: []const u8,
+    value: []const u8,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write(self.key);
+        f.write(": \"");
+        f.write(self.value);
+        f.writeChar('"');
+    }
+};
+
+pub const ExportDecl = struct {
+    loc: Loc,
+    declaration: ?*const Decl,
+    specifiers: ?[]const ExportSpecifier,
+    source: ?[]const u8,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("export ");
+        if (self.declaration) |d| {
+            d.*.fmt(f);
+        } else if (self.specifiers) |s| {
+            f.writeChar('{');
+            for (s, 0..) |sp, i| {
+                if (i > 0) f.write(", ");
+                sp.fmt(f);
+            }
+            f.writeChar('}');
+            if (self.source) |src| {
+                f.write(" from \"");
+                f.write(src);
+                f.writeChar('"');
+            }
+            f.writeChar(';');
+        } else if (self.source) |src| {
+            f.write("* from \"");
+            f.write(src);
+            f.writeChar("\";");
+        }
+    }
+};
+
+pub const ExportSpecifier = struct {
+    loc: Loc,
+    exported: []const u8,
+    local: []const u8,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write(self.local);
+        if (!std.mem.eql(u8, self.local, self.exported)) {
+            f.write(" as ");
+            f.write(self.exported);
+        }
+    }
+};
+
+pub const ExportDefault = struct {
+    loc: Loc,
+    declaration: *const Decl,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.write("export default ");
+        self.declaration.*.fmt(f);
+    }
+};
+
+pub const ArrayExpr = struct {
+    loc: Loc,
+    elems: []const ?Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('[');
+        for (self.elems, 0..) |elem, i| {
+            if (i > 0) f.write(", ");
+            if (elem) |e| e.fmt(f);
+        }
+        f.writeChar(']');
+    }
+};
+
+pub const ObjectExpr = struct {
+    loc: Loc,
+    props: []const Prop,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('{');
+        for (self.props, 0..) |p, i| {
+            if (i > 0) f.write(", ");
+            p.fmt(f);
+        }
+        f.writeChar('}');
+    }
+};
+
+pub const MemberExpr = struct {
+    loc: Loc,
+    obj: *const Expr,
+    prop: union(enum) {
+        ident: []const u8,
+        private: []const u8,
+    },
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        self.obj.*.fmt(f);
+        switch (self.prop) {
+            .ident => |name| {
+                f.writeChar('.');
+                f.write(name);
+            },
+            .private => |name| {
+                f.writeChar('.');
+                f.write(name);
+            },
+        }
+    }
+};
+
+pub const ComputedMember = struct {
+    loc: Loc,
+    obj: *const Expr,
+    expr: *const Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        self.obj.*.fmt(f);
+        f.writeChar('[');
+        self.expr.*.fmt(f);
+        f.writeChar(']');
+    }
+};
+
+pub const CallExpr = struct {
+    loc: Loc,
+    callee: *const Expr,
+    args: []const Expr,
+    optional: bool,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        self.callee.*.fmt(f);
+        if (self.optional) {
+            f.write("?.(");
+        } else {
+            f.writeChar('(');
+        }
+        for (self.args, 0..) |a, i| {
+            if (i > 0) f.write(", ");
+            a.fmt(f);
+        }
+        f.writeChar(')');
+    }
+};
+
+pub const NewExpr = struct {
+    loc: Loc,
+    callee: *const Expr,
+    args: []const Expr,
+};
+
+pub const ChainExpr = struct {
+    loc: Loc,
+    expr: *const Expr,
+};
+
+pub const UnaryOp = enum {
+    @"-",
+    @"+",
+    @"!",
+    @"~",
+    typeof,
+    void,
+    delete,
+};
+
+pub const UnaryExpr = struct {
+    loc: Loc,
+    op: UnaryOp,
+    arg: *const Expr,
+    prefix: bool,
+};
+
+pub const BinaryOp = enum {
+    @"==",
+    @"!=",
+    @"===",
+    @"!==",
+    @"<",
+    @"<=",
+    @">",
+    @">=",
+    @"<<",
+    @">>",
+    @">>>",
+    @"+",
+    @"-",
+    @"*",
+    @"/",
+    @"%",
+    @"**",
+    @"|",
+    @"^",
+    @"&",
+    in,
+    instanceof,
+    @"||",
+    @"&&",
+    @"??",
+};
+
+pub const BinaryExpr = struct {
+    loc: Loc,
+    op: BinaryOp,
+    left: *const Expr,
+    right: *const Expr,
+};
+
+pub const UpdateOp = enum {
+    @"++",
+    @"--",
+};
+
+pub const UpdateExpr = struct {
+    loc: Loc,
+    op: UpdateOp,
+    arg: *const Expr,
+    prefix: bool,
+};
+
+pub const IfExpr = struct {
+    loc: Loc,
+    condition: *const Expr,
+    consequent: *const Expr,
+    alternate: *const Expr,
+};
+
+pub const AssignOp = enum {
+    @"=",
+    @"+=",
+    @"-=",
+    @"*=",
+    @"/=",
+    @"%=",
+    @"**=",
+    @"<<=",
+    @">>=",
+    @">>>=",
+    @"|=",
+    @"^=",
+    @"&=",
+    @"||=",
+    @"&&=",
+    @"??=",
+};
+
+pub const AssignExpr = struct {
+    loc: Loc,
+    op: AssignOp,
+    left: *const Expr,
+    right: *const Expr,
+};
+
+pub const SeqExpr = struct {
+    loc: Loc,
+    exprs: []const Expr,
+};
+
+pub const YieldExpr = struct {
+    loc: Loc,
+    arg: ?*const Expr,
+    delegate: bool,
+};
+
+pub const AwaitExpr = struct {
+    loc: Loc,
+    arg: *const Expr,
+};
+
+pub const MetaProp = struct {
+    loc: Loc,
+    meta: []const u8,
+    prop: []const u8,
+};
+
+pub const TemplateLit = struct {
+    loc: Loc,
+    quasis: []const TemplateElem,
+    exprs: []const Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('`');
+        var ei: usize = 0;
+        for (self.quasis, 0..) |q, i| {
+            if (i > 0 and ei < self.exprs.len) {
+                f.write("${");
+                self.exprs[ei].fmt(f);
+                f.writeChar('}');
+                ei += 1;
+            }
+            f.write(q.value);
+        }
+        f.writeChar('`');
+    }
+};
+
+pub const TemplateElem = struct {
+    loc: Loc,
+    value: []const u8,
+    tail: bool,
+};
+
+pub const TaggedTemplate = struct {
+    loc: Loc,
+    tag: *const Expr,
+    quasi: TemplateLit,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        self.tag.*.fmt(f);
+        self.quasi.fmt(f);
+    }
+};
+
+pub const Decorator = struct {
+    loc: Loc,
+    expr: *const Expr,
+
+    pub fn fmt(self: @This(), f: *Formatter) void {
+        f.writeChar('@');
+        self.expr.*.fmt(f);
+    }
+};