pub fn is_digit(char: String) -> Bool

pub fn is_end_of_input(char: String) -> Bool

pub fn is_end_of_segment(char: String) -> Bool

pub fn is_identifier_char(char: String) -> Bool

pub fn is_letter(char: String) -> Bool

pub fn is_punctuator_start(char: String) -> Bool

pub fn is_whitespace(char: String) -> Bool