Question 10452 – Context-Free-Grammar

A simple Pascal like language has only three statements.
(i) assignment statement e.g. x:=expression
(ii) loop construct e.g. for i:=expression to expression do statement.
(iii) sequencing e.g. begin statement ;…; statement end

(a) Write a context-free grammar (CFG) for statements in the above language. Assume that expression has already been defined. Do not use optional
parentheses and * operator in CFG.
(b) Show the parse tree for the following statement:

     for j:=2 to 10 do
         begin x:=expr1;
               y:=expr2
         end  

Correct Answer: A