parsing

Question

which of the following statements is true?

A) right recursion is needed for termination in predictive parser

B) left recursion is required more stack space than right recursion

C) left recursion works fine in BUP

1)A & B

2) A & C
3) B & C
4) All

Answer 1

A and C are correct.

1)In predictive parser we use right recursive and deterministic grammer and do top down parsing. So by using RR chance of infinite recursion is avoided. So its true.

2) Actually its the other way around. right recursive grammars, the stack may grow indefinitely until a reduction occurs, thus limiting rather dramatically the parsing possibilities. However, left recursive ones will let the compiler generate reductions earlier (in fact, as soon as possible). So its false. 

3) Yes, Its the advantage of BUP actually. http://jeffreykegler.github.io/Ocean-of-Awareness-blog/individual/2014/11/ll.html

Answer 2

i think B and C are true .but , B is absolutly fine its correct there is no doubt in that .

option A is FALSE because in order to stop an PARSER we need EPSILON  but not an RIGHT /LEFT  RECURSIVE GRAMMAR