Page 214 - DCAP507_SYSTEM_SOFTWARE

System Software

Notes 3. Illustrate the process of parsing context-free grammars.
4. Even though natural languages can stand some type of ambiguity (e.g., puns, plays on
words, etc.), it is not suitable in computer languages. Comment.

5. What are recursive productions? Illustrate with examples.
6. What is Backus Naur Form (BNF)? Explicate with examples.
7. Describe the concept of Extensions in BNF. Also discuss Data type definitions for extensions
with example.
8. Describe the Algol 60 compound statement in unextended BNF.
9. The variable-declaration part of a Pascal program, procedure definition, or function
definition consists of the keyword var followed by one or more declarations, each consisting
of one or more identifiers (separated by commas), a colon, and either an identifier or a
constructed type. Each declaration is terminated by a semicolon.
10. Translate this description into one or more BNF rules. (You can assume that the category
<constructed-type> is defined elsewhere.) Then write a data type definition for it.

Answers: Self Assessment

1. Type 0 (free or unobstructed grammars) 2. Type 1 (context-sensitive grammars)

3. Type 2 (context-free grammars), 4. non-terminals
5. parsers 6. ambiguous
7. left-recursive 8. type 1

9. context-free 10. Backus Naur Form
11. trees 12. syntactic
13. angle brackets 14. rules
15. Peter Naur

13.6 Further Readings

Books Chattopadhyay, System Software, PHI Learning Pvt. Ltd.

Donovan, Systems Programming, Tata McGraw-Hill Education
I.A. Dhotre A.A. Puntambekar, Systems Programming, Technical Publications
M. Joseph, System Software, Firewall Media

Online link www.springer.com

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