1 files changed, 553 insertions, 0 deletions
diff --git a/src/z/parser/js/parser.zig b/src/z/parser/js/parser.zig
new file mode 100644
index 0000000..09118dd
--- /dev/null
+++ b/src/z/parser/js/parser.zig
@@ -0,0 +1,553 @@
+const std = @import("std");
+const lex = @import("lexical_grammar.zig");
+const Token = lex.Token;
+const TokenType = lex.TokenType;
+const ast = @import("ast/core.zig");
+
+pub const ParseError = error{
+    UnexpectedToken,
+    ExpectedToken,
+    ExpectedExpression,
+    ExpectedStatement,
+    ExpectedIdentifier,
+    UnclosedString,
+    InvalidNumber,
+    InvalidEscape,
+    UnterminatedComment,
+    ExpectedParameterName,
+    ExpectedPropertyName,
+    UnterminatedTemplate,
+    InvalidAssignmentTarget,
+    TooManyTokens,
+};
+
+pub const BP = struct {
+    pub const comma = 1;
+    pub const assign = 2;
+    pub const yield = 3;
+    pub const conditional = 4;
+    pub const coalesce = 5;
+    pub const log_or = 6;
+    pub const log_and = 7;
+    pub const bit_or = 8;
+    pub const bit_xor = 9;
+    pub const bit_and = 10;
+    pub const equality = 11;
+    pub const relational = 12;
+    pub const shift = 13;
+    pub const additive = 14;
+    pub const multiplicative = 15;
+    pub const exponentiation = 16;
+    pub const unary = 17;
+    pub const update = 18;
+    pub const call = 19;
+    pub const member = 20;
+};
+
+pub const NodeArena = struct {
+    exprs: [8192]ast.Expr = undefined,
+    expr_count: usize = 0,
+    stmts: [8192]ast.Stmt = undefined,
+    stmt_count: usize = 0,
+    decls: [1024]ast.Decl = undefined,
+    decl_count: usize = 0,
+    pats: [1024]ast.Pat = undefined,
+    pat_count: usize = 0,
+    lits: [1024]ast.Lit = undefined,
+    lit_count: usize = 0,
+    string_buf: [65536]u8 = undefined,
+    string_pos: usize = 0,
+
+    pub fn exprPtr(self: *NodeArena, data: ast.ExprType, loc: ast.Loc) *const ast.Expr {
+        const idx = self.expr_count;
+        self.exprs[idx] = .{ .loc = loc, .data = data };
+        self.expr_count += 1;
+        return &self.exprs[idx];
+    }
+
+    pub fn stmtPtr(self: *NodeArena, data: ast.StmtType, loc: ast.Loc) *const ast.Stmt {
+        const idx = self.stmt_count;
+        self.stmts[idx] = .{ .loc = loc, .data = data };
+        self.stmt_count += 1;
+        return &self.stmts[idx];
+    }
+
+    pub fn declPtr(self: *NodeArena, data: ast.DeclType, loc: ast.Loc) *const ast.Decl {
+        const idx = self.decl_count;
+        self.decls[idx] = .{ .loc = loc, .data = data };
+        self.decl_count += 1;
+        return &self.decls[idx];
+    }
+
+    pub fn patPtr(self: *NodeArena, data: ast.PatType, loc: ast.Loc) *const ast.Pat {
+        const idx = self.pat_count;
+        self.pats[idx] = .{ .loc = loc, .data = data };
+        self.pat_count += 1;
+        return &self.pats[idx];
+    }
+
+    pub fn litPtr(self: *NodeArena, data: ast.LitType, loc: ast.Loc) *const ast.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 };
+    }
+
+    pub fn tok(self: *@This()) Token {
+        return self.tokens[self.pos];
+    }
+
+    pub fn peek(self: *@This()) TokenType {
+        return self.tokens[self.pos].kind;
+    }
+
+    pub fn peekAt(self: *@This(), offset: usize) TokenType {
+        const idx = self.pos + offset;
+        if (idx >= self.tokens.len) return .eof;
+        return self.tokens[idx].kind;
+    }
+
+    pub fn advance(self: *@This()) void {
+        self.pos += 1;
+    }
+
+    pub fn advanceTok(self: *@This()) Token {
+        const t = self.tokens[self.pos];
+        self.pos += 1;
+        return t;
+    }
+
+    pub fn expect(self: *@This(), kind: TokenType) ParseError!void {
+        if (self.peek() != kind) return ParseError.ExpectedToken;
+        self.advance();
+    }
+
+    pub fn expectTok(self: *@This(), kind: TokenType) ParseError!Token {
+        if (self.peek() != kind) return ParseError.ExpectedToken;
+        return self.advanceTok();
+    }
+
+    pub fn match(self: *@This(), kind: TokenType) bool {
+        if (self.peek() == kind) {
+            _ = self.advanceTok();
+            return true;
+        }
+        return false;
+    }
+
+    pub fn matchKeyword(self: *@This(), kw: TokenType) bool {
+        if (self.peek() == kw) {
+            _ = self.advanceTok();
+            return true;
+        }
+        return false;
+    }
+
+    pub 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;
+    }
+
+    pub fn as_identifier(self: *@This(), t: Token) []const u8 {
+        return self.source[t.loc.start..t.loc.end];
+    }
+
+    pub fn tokenSlice(self: *@This(), t: Token) []const u8 {
+        return self.source[t.loc.start..t.loc.end];
+    }
+
+    pub fn parseForDeclaration(self: *@This()) ParseError!*const ast.Decl {
+        const kind_tok = self.advanceTok();
+        var decls: [128]ast.VarDeclarator = undefined;
+        var count: usize = 0;
+
+        while (true) {
+            const pat = try ast.Pat.parse(self);
+            var decl_init: ?*const ast.Expr = null;
+            if (self.match(.@"=")) {
+                decl_init = try ast.Expr.parse(self, 0);
+            }
+            decls[count] = .{ .loc = pat.loc, .id = pat, .init = decl_init };
+            count += 1;
+            if (!self.match(.comma)) break;
+        }
+
+        const kind: ast.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 });
+    }
+
+    pub fn parseParams(self: *@This()) ParseError![]const ast.Pat {
+        try self.expect(.lparen);
+        var params: [128]ast.Pat = undefined;
+        var count: usize = 0;
+
+        if (self.peek() != .rparen) {
+            while (true) {
+                if (self.peek() == .@"...") {
+                    self.advance();
+                    const pat = try ast.Pat.parse(self);
+                    params[count] = ast.Pat{ .loc = pat.loc, .data = .{ .rest = .{ .loc = pat.loc, .arg = self.arena.patPtr(pat.data, pat.loc) } } };
+                    count += 1;
+                    break;
+                }
+                const pat = try ast.Pat.parse(self);
+                if (self.match(.@"=")) {
+                    const expr = try ast.Expr.parse(self, 0);
+                    params[count] = ast.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 ast.Pat.parse(self);
+                    params[count] = ast.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];
+    }
+
+    pub fn parseFunctionBody(self: *@This()) ParseError!ast.BlockStmt {
+        return ast.BlockStmt.parse(self);
+    }
+
+    pub fn parsePrimaryExpr(self: *@This()) ParseError!*const ast.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 ast.ObjectExpr.parse(self),
+            .lbracket => return ast.ArrayExpr.parse(self),
+            .lparen => {
+                self.advance();
+                if (self.peek() == .rparen) {
+                    self.advance();
+                    if (self.peek() == .@"=>") {
+                        return ast.ArrowFn.parse(self, .{ .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 ast.Expr.parse(self, 0);
+                    try self.expect(.rparen);
+                    if (self.peek() == .@"=>") {
+                        return ast.ArrowFn.parse(self, .{ .loc = .{ .start = start, .end = arg.loc.end }, .params = &.{} });
+                    }
+                    const loc: ast.Loc = .{ .start = start, .end = self.tok().loc.start };
+                    return self.arena.exprPtr(.{ .spread = .{ .loc = loc, .arg = arg } }, loc);
+                }
+                const expr = try ast.Expr.parse(self, 0);
+                if (self.peek() == .comma) {
+                    var params: [128]ast.Pat = undefined;
+                    var count: usize = 0;
+                    params[count] = ast.Pat{ .loc = expr.loc, .data = .{ .ident = expr.data.identifier } };
+                    count += 1;
+                    while (self.match(.comma)) {
+                        const p = try ast.Pat.parse(self);
+                        params[count] = p;
+                        count += 1;
+                    }
+                    try self.expect(.rparen);
+                    if (self.peek() == .@"=>") {
+                        return ast.ArrowFn.parse(self, .{ .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 = ast.Pat{ .loc = expr.loc, .data = .{ .ident = expr.data.identifier } };
+                    return ast.ArrowFn.parse(self, .{ .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 ast.FnExpr.parse(self),
+            .class => return ast.ClassExpr.parse(self),
+            .async => {
+                self.advance();
+                if (self.peek() == .function) {
+                    return ast.FnExpr.parse(self);
+                }
+                const id_tok = try self.expectTok(.identifier);
+                const name = self.tokenSlice(id_tok);
+                if (self.peek() == .@"=>") {
+                    const pat = ast.Pat{ .loc = .{ .start = start, .end = id_tok.loc.end }, .data = .{ .ident = name } };
+                    return ast.ArrowFn.parse(self, .{ .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 ast.Expr.parse(self, BP.member);
+                var args: [256]ast.Expr = undefined;
+                var arg_count: usize = 0;
+                if (self.peek() == .lparen) {
+                    self.advance();
+                    if (self.peek() != .rparen) {
+                        while (true) {
+                            const arg = try ast.Expr.parse(self, 0);
+                            args[arg_count] = arg.*;
+                            arg_count += 1;
+                            if (!self.match(.comma)) break;
+                        }
+                    }
+                    try self.expect(.rparen);
+                }
+                const loc: ast.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 ast.Expr.parse(self, BP.unary);
+                const loc: ast.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 ast.Expr.parse(self, BP.update);
+                const loc: ast.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 ast.Expr.parse(self, BP.update);
+                const loc: ast.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 ast.Expr.parse(self, BP.unary);
+                const loc: ast.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 ast.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 ast.Expr.parse(self, 0);
+                    }
+                }
+                const loc: ast.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 ast.TemplateLit.parse(self) }, .{ .start = start, .end = self.tok().loc.start }),
+            .import => {
+                self.advance();
+                try self.expect(.lparen);
+                _ = try ast.Expr.parse(self, 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 = ast.Pat{ .loc = .{ .start = t.loc.start, .end = t.loc.end }, .data = .{ .ident = name } };
+                        return ast.ArrowFn.parse(self, .{ .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;
+            },
+        }
+    }
+
+    pub fn parsePropKey(self: *@This()) ParseError!ast.PropKey {
+        switch (self.peek()) {
+            .identifier, .let, .static, .get, .set, .async => {
+                const t = self.advanceTok();
+                return ast.PropKey{ .ident = self.tokenSlice(t) };
+            },
+            .string => {
+                const t = self.advanceTok();
+                return ast.PropKey{ .string = self.tokenSlice(t) };
+            },
+            .number => {
+                const t = self.advanceTok();
+                const val = std.fmt.parseFloat(f64, self.tokenSlice(t)) catch 0.0;
+                return ast.PropKey{ .number = val };
+            },
+            .lbracket => {
+                self.advance();
+                const expr = try ast.Expr.parse(self, 0);
+                try self.expect(.rbracket);
+                return ast.PropKey{ .computed = expr };
+            },
+            .private_identifier => {
+                const t = self.advanceTok();
+                return ast.PropKey{ .private = self.tokenSlice(t) };
+            },
+            else => return ParseError.ExpectedPropertyName,
+        }
+    }
+
+    pub 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,
+        };
+    }
+
+    pub fn unaryOpFromToken(self: *@This()) ast.UnaryOp {
+        return switch (self.tok().kind) {
+            .@"+" => .@"+",
+            .@"-" => .@"-",
+            .@"!" => .@"!",
+            .@"~" => .@"~",
+            .typeof => .typeof,
+            .void => .void,
+            .delete => .delete,
+            else => .@"+",
+        };
+    }
+
+    pub fn assignOpFromToken(self: *@This()) ast.AssignOp {
+        return switch (self.tokens[self.pos - 1].kind) {
+            .@"=" => .@"=",
+            .@"+=" => .@"+=",
+            .@"-=" => .@"-=",
+            .@"*=" => .@"*=",
+            .@"/=" => .@"/=",
+            .@"%=" => .@"%=",
+            .@"**=" => .@"**=",
+            .@"<<=" => .@"<<=",
+            .@">>=" => .@">>=",
+            .@">>>=" => .@">>>=",
+            .@"&=" => .@"&=",
+            .@"|=" => .@"|=",
+            .@"^=" => .@"^=",
+            .@"&&=" => .@"&&=",
+            .@"||=" => .@"||=",
+            .@"??=" => .@"??=",
+            else => .@"=",
+        };
+    }
+
+    pub fn semicolon(self: *@This()) void {
+        if (self.peek() == .semicolon) {
+            self.advance();
+        }
+    }
+
+    pub fn statementPointer(self: *@This()) ParseError!*const ast.Stmt {
+        const s = try ast.Stmt.parse(self);
+        return self.arena.stmtPtr(s.data, s.loc);
+    }
+};