Zephyr ASDL

-- ASDL's 6 builtin types are:
-- identifier, int, string, bytes, object, singleton

module Python
{
    mod = Module(stmt* body, type_ignore* type_ignores)
        | Interactive(stmt* body)
        | Expression(expr body)
        | FunctionType(expr* argtypes, expr returns)

    stmt = FunctionDef(identifier name, arguments args,
                       stmt* body, expr* decorator_list, expr? returns,
                       string? type_comment)
          | AsyncFunctionDef(identifier name, arguments args,
                              stmt* body, expr* decorator_list, expr? returns,
                              string? type_comment)
          | ClassDef(identifier name,
             expr* bases,
             keyword* keywords,
             stmt* body,
             expr* decorator_list)
          | Return(expr? value)
          | Delete(expr* targets)
          | Assign(expr* targets, expr value, string? type_comment)
          | If(expr test, stmt* body, stmt* orelse)
          | While(expr test, stmt* body, stmt* orelse)
          | For(expr target, expr iter, stmt* body, stmt* orelse,
                string? type_comment)

    expr = BoolOp(boolop op, expr* values)
         | BinOp(expr left, operator op, expr right)
         | UnaryOp(unaryop op, expr operand)
         | Name(identifier id, expr_context ctx)
         | Constant(constant value, string? kind)

    boolop = And | Or

    expr_context = Load | Store | Del

    operator = Add | Sub | Mult | MatMult | Div | Mod | Pow
             | LShift | RShift | BitOr | BitXor | BitAnd | FloorDiv

    unaryop = Invert | Not | UAdd | USub
}