Consider the following grammar (G1) for simple assignment statements. (The symbols in double quotation marks are terminal symbols.)

assign id = expr

id A | B | C

expr expr + expr

| expr expr

| ( expr )

| id

a) Give a (leftmost) derivation for string A = B A + C.

b) Give the parse tree for string A = B A + C.

c) Is the grammar ambiguous or unambiguous? Explain your answer.

d) Consider the following grammar (G2).

assign id = expr

id A | B | C

expr id + expr

| id expr

| ( expr )

| id

What is the difference between G2 and G1? Explain your answer