GATE | GATE CS 2019 | Question 13
Which one of the following kinds of derivation is used by LR parsers?
(B) Leftmost in reverse
(D) Rightmost in reverse
Explanation: Parsing is classified into two categories, i.e. Top Down Parsing and Bottom-Up Parsing. Top-Down Parsing is based on Left Most Derivation whereas Bottom Up Parsing is dependent on Reverse Right Most Derivation.
A general shift reduce parsing is LR parsing is bottom-up parsing where L stands for scanning the input from left to right and R stands for constructing a rightmost derivation in reverse.
So, option (D) is correct.