2.12 Lookup Tables

• Lookup tables can be used for simplifying DFSAs that model syntax analyzers

  LET GOTO IF END

• A scanner returns a pair for each token

  (lexical type for the parser, attribute for the code generator)

  Lookup tables can be generalized for handling attribute values.

  symbol syntax attribute LET 0 — GOTO 1 — IF 2 — END 3 — ( 4 — ) 5 — + 6 0 - 6 1 * 7 0 / 7 1 <id> 8 pointer to symbol table <integer> 9 pointer to constant table

  symbol table 0 LET 1 GOTO 2 IF 3 END   $⋮$ id $⋮$ constant table 0 1 $⋮$ $⋮$ int $⋮$