Parse trees and derivations in Compiler Design - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to represent the root of a parse tree.

Compiler Design

root = ParseTreeNode([1])

Drag options to blanks, or click blank then click option'

Aexpression

Btoken

Cgrammar

Dsyntax

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'grammar' or 'syntax' instead of a token for the root node.

The root of a parse tree typically holds a token representing the start symbol or main expression.

2fill in blank

medium

Complete the code to create a derivation step from a non-terminal to a production.

Compiler Design

derivation = DerivationStep([1], production_rule)

Drag options to blanks, or click blank then click option'

Anon_terminal

Bterminal

Ctoken

Dleaf

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing terminal and non-terminal symbols in derivations.

A derivation step starts from a non-terminal symbol and applies a production rule.

3fill in blank

hard

Fix the error in the code to correctly build a parse tree node with children.

Compiler Design

node = ParseTreeNode(symbol=[1], children=children_list)

Drag options to blanks, or click blank then click option'

Anon_terminal

Btoken

Cproduction

Dterminal

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'token' or 'terminal' for nodes that have children.

Parse tree nodes represent non-terminal symbols with children nodes representing expansions.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension mapping non-terminals to their productions.

Compiler Design

{ [1]: [2] for [1] in grammar.non_terminals }

Drag options to blanks, or click blank then click option'

Ant

Bproduction_list

Csymbol

Drule

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'symbol' or 'rule' as keys or values incorrectly.

This comprehension maps each non-terminal (nt) to its list of productions.

5fill in blank

hard

Fill all three blanks to filter productions that derive a terminal symbol.

Compiler Design

[prod for prod in productions if prod.[1] == [2] and prod.[3]]

Drag options to blanks, or click blank then click option'

Aleft_side

Bterminal

Cis_terminal

Dright_side

Attempts:

3 left

💡 Hint

Common Mistakes

Checking left_side instead of right_side.

Confusing property names.

This list comprehension selects productions whose right side is a terminal and confirms it is terminal.