let is_line_terminator: env => bool;
let is_implicit_semicolon: env => bool;
let is_identifier: env => bool;
let is_type_identifier: env => bool;
let is_identifier_name: env => bool;
let is_function: env => bool;
let is_class: env => bool;
let ith_is_line_terminator: i:int => env => bool;
let ith_is_implicit_semicolon: i:int => env => bool;
let ith_is_identifier: i:int => env => bool;
let ith_is_identifier_name: i:int => env => bool;
let ith_is_type_identifier: i:int => env => bool;