1. CMSC 330 - Spring 2011 Top-Down Parsing E → id = n | { L } L → E ; L | ε (Assume: id is variable name, n is integer) Show parse tree for { x = 3 ; { y = 4 ; } ; } 1 E L EL EL ε L E L ε

2. CMSC 330 - Spring 2011 Bottom-up Parsing E → id = n | { L } L → E ; L | ε Show parse tree for { x = 3 ; { y = 4 ; } ; } Note that final trees constructed are same as for top-down; only order in which nodes are added to tree is different 2 { x = 3 ; { y = 4 ; } ; } E L EL EL ε L E L ε

3. CMSC 330 - Spring 2011 Recursive Descent Example E → id = n | { L } L → E ; L | ε { x = 3 ; { y = 4 ; } ; } E {L} E;L x=3E;L {L} E; L y=4ε ε lookahead 3