<letter> --> a | b | ... | y | z | A | B | ... | Z | underscore
<identifier> --> <letter> (<letter> | <digit>)*
<digit> --> 0 | 1 | ... | 9
<number> --> <digit>+
<reserved word> --> int | void | if | while | return | read | write | print | continue | break | binary | decimal
<symbol> --> left_parenthesis | right_parenthesis
| left_brace | right_brace | left_bracket | right_bracket
|
comma
| semicolon | plus_sign | minus_sign | star_sign
| forward_slash | == | != | > | >= |
<
| <= | equal_sign | double_and_sign | double_or_sign
(The symbols are: ( ) { } [ ] , ; + - * / == != > >= < <=
= && ||)
<string> --> any string between (and including) the closest
pair of quotation marks.
<meta statement> --> any string begins with '#' or '//' and
ends with the end of line ('\n').