Question

Problem I. Parsing. Consider the grammar SAg BC (1) A a A A CB B dBc 2. Show that the grammar has a predictive recursive descent parser

Answer 1

Rightarrow To construct predictor parser, we have to find first and follow symbols of grammer variables S rightarrow Ag BC (1) A rightarrow aA (2) A rightarrow cB (3) B rightarrow d Bc (4) B rightarrow epsilon (5) C rightarrow fc (6) C rightarrow epsilon (7) Rightarrow First of S: - S = {a, f, d, g} * first of A: A = {a, f, d, epsilon} * first of B B = {d, epsilon} * first of C C = {f, epsilon} \r\n first follow S afdg $ A afdg g B d epsilon $ fgc C f epsilon $ dg \r\n parser (or) parse Table a c d f g $ S S rightarrow Ag Bc S rightarrow Ag Bc S rightarrow Ag Bc S rightarrow Ag Bc A A rightarrow aA A rightarrow CB A rightarrow CB A rightarrow CB A rightarrow CB B B rightarrow epsilon B rightarrow d BC B rightarrow epsilon B rightarrow epsilon B rightarrow epsilon