Table Driven Implementation for DFSAs

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2.9 Table Driven Implementation for DFSAs

state = q0
WHILE( ! end-of-file )
{
  char = nextChar()
  state = table[state,char];
  IF( undefined( state ) ){ reject(); }
}
IF( final(state) ){ accept(); }
ELSE              { reject(); }


	a	b

q0	q0	q1

q1	q0	q2

q2		q2

a|-
|||-
|| - ||||b|||||| |||b||||||-
-- -q0o |||||||||| q1o -||||||||||q2Oo
a b

States and symbols can be encoded, e.g., as integers

Sparse tables can be more economically saved, e.g., as pairs of tables.

row #	start row	number of elements in row

$⋮$
i	î	r
$⋮$

	column #	next state

$⋮$
î	$j_{1}$	$v_{1}$
$⋮$	$⋮$	$⋮$
î+r-1	$j_{r}$	$v_{r}$
$⋮$