Token language

The tokens include identifiers (ID), numbers (NUMBER), 8 reserved words and 15 symbols.  They are defined as regular expressions as follows:

<letter> --> a | b | ... | y | z
ID --> <letter> +

<digit> --> 0 | 1 | ... | 9
NUMBER --> <digit>+

<reserved words> --> int | int2 | int10 | void if | while | return | read | write

<symbols> --> left_parenthesis | right_parenthesis | left_brace | right_brace | comma | semicolon | plus_sign | minus_sign | star_sign | forward_slash | == | != | > | >= | equal_sign
(The 15 symbols are: ( ) { } , ; + - * / == != > >= =)