1) Token attributes may vary
 [id,EPos],       [int, 60],       [*,     ]
Tokens in Practice
pointer
integer
nothing
20/35
• tokens represent every SP lexeme in a uniform way
• in general, their form is
[type,  attribute]
NOTE: In practice, we often use tokens whose attributes vary.
2) The same form of tokens
[1, 2], [2, 3], [3, 1]