Question

1.Use the action/goto table for the grammar below (where the productions are as numbered) to parse the incorrect input string:

      ( 2 ( ) ) 5 ) 6 )
When the syntax error is detected, a) what does the stack look like, b) what was the last action and c) what is the lookahead?

1: R->S

2.S->(L)L

3.S-> ε

4.L->int L

5. L->S

state	(	)	int	$	S	L
0	s2	r3		r3	1
1				acc
2	s2	r3	s4	r3	5	3
3		s6
4	s2	r3	s4	r3	5	7
5		r5		r5
6	s2	r3	s4	r3	5	8
7		r4		r4
8		r2		r2

Answer 1

Explanation For given Solution:

In step number 1 , stack content is $I0, where $ indicates stack start symbol and I0 is initial state.In table(Action/Goto), On state I0 if input symbol is ( , shift action occur and symbol shift into stack.

All shift actions in this manner only.

In step number 4 there is no ymbol on RHS of production so just place S into stack and if I2 gets S in gototablegoes to I5, so put I5.

In state number 16 when we reducing there are 4 symbols on RHS of production so remove 8(4multiply by 2)symbols from stack.

For complete solution see the images.

have to parse the third (21))5%) (21))526), t shift to (12 15) ) 61(1 214 (121 1s )54 リー 2101, 24117, redue S-E vedute Sa (1) L. 6) achirn when the tte e dekcled stack boks like (c) Here look thead mbo

See step number 16. Here I7 and input ) , reduce by production number4. i.e L->int L

Now Stack content would be $I0(I2LI3)I6LI8

Now reduce by second production , After reduction stack contend would be $I0I1 .

For I1 and ) , there is no entry in table means error