value ; expr ; term ; the following context-tree grammar: : 'IF' expr 'THEN' expr 'ELSE' expr | 'IF' expr 'THEN' expr | expr : expr '+' term | term : 'a' | 'b' | 'c' | 'd' 'e' Ignoring whitespaces, draw a parse tree for IF a THEN b + c + d ELSE e The grammar has several undesirable features-what are they? Illustrate them by examples as necessary, and explain why they are problematic. What could be done to overcome the problems in the previous question?

Use the bison framework to build a DFA state machine for each of the following grammars. Identify any possible conflicts causing the bottom-up parsing to fail. Make sure to complete the missing closures in each state. 1) expr expr '+' term | expr'-' term | term term – term ** primary | primary primary → ID | (' expr ')' |'-' primary 2) expr → expr '+' term | term term - term * primary | primary primary - ID | '(' expr ')' expr '+' term | expr'-' term | term term *" primary| primary primary → ID | '(' expr ')' | '' primary | ID '(' expr ')' 3) expr term

3. For the expression A=B*(A-C) where -, *,=, and brackets are operation, number of leaves in parse tree are: а. 12 b. 9 c. 8 d. 7 Use the following grammar: -> = -> A | B|C -> * | - | ()[

q2q4