ParseIT

Abstract

Compiler design is an important subject in the computer science curriculum for undergraduates. In a typical Compiler's course, about 15%-22% of the total time is spent on syntax analysis phase (also called parsing techniques). A number of concepts are introduced to explain the internals of parsers, for example first set, follow set, item set, goto and closure set, parse tables and the parsing algorithms, making the understanding difficult. While parser generators (YACC and its variants) allow the students to experiment with grammars, the working of the parser generated by the tools is still opaque.We present ParseIT, a web based tool to help students understand the concept of parsing in an undergraduate Compiler Design course. Given a grammar, the tool generates multiple choice questions for concepts related to parsing. The tool evaluates students' attempts and provide hints for incorrect attempts. The hints are also generated in the form of specific questions about any correct choice that is missed or any incorrect choice that is selected. For grammars that can be parsed through the textbook LL or LR algorithms, an interesting form of hint generated is an input string that helps student identify incorrectly filled cells of a parsing table. The tool enables interactive and active learning of parsing concepts, resulting in a better understanding.