Context
(
X
)
for Predictive Parser: Variant
I
I
56/57
For
G
= (
N
,
T
,
P
,
S
)
,
Context
(
A
) =
First
(
A
)
È
Follow
(
A
) for every
A
Î
N
•
Method:
•
Let
A
be push
down
top
& no rule is applicable:
•
repeat
a
:= GetNextToken;
{These tokens are skipped}
until
a
in
Context
(
A
)
•
if
a
Î
First
(
A
)
then
resume according to
A
else
pop
A
from the pushdown
//
a
Î
Follow
(
A
)