CD

[amol.b]

Which of the following describes a handle (as applicable to LR-
parsing)
appropriately?
(A) It is the position in a sentential form where the next shift or
reduce operation
will occur
(B) It is non-terminal whose production will be used for reduction in
the next
step
(C) It is a production that may be used for reduction in a future step
along with a
position in the sentential form where the next shift or reduce
operation will
occur
(D) It is the production p that will be used for reduction in the next
step along
with a position in the sentential form where the right hand side of
the
production may be found

I have confusion in option c and d
whether handle is used in context of reduction only?

[Mayur Mahrotri]

    -Yes

A handle of a sentential form is a substring "x" such that :
– "x" matches the RHS of a production A -> x ; and
– replacing "x" by the LHS A represents a step in the
reverse of a rightmost derivation of s.

Answer is (d) because of the word "next step".

Handle is not exactly a production, it is a substring of a sentential form, which matches the right hand side of any production, and which will be replaced in the next step by the Left hand side of that production.

--
With Regards,
Mayur.