Prolog

The following BNF grammar is based on the syntax of statements in Pascal: rightarrow id: = expr |if expr then |if expr then else |while expr do |begin end rightarrow S: | : Token id represents a variable and token expr represent an expression. (a) Draw parse trees for each of the following: a. while expr do id: = expr b. begin id: = expr then else c. if expr then if expr then else (b) Show a leftmost derivation for each of the strings in part (a) above