Computer Science 433
Programming Languages

Fall 2012, The College of Saint Rose

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Agenda

• Announcements
• Back to regular grammars briefly
• Lexical analysis
  • The "front" lexical analysis for simple arithmetic expressions
• Parsing
  • Recursive descent parsing

Lecture Assignment 9

Due at the start of class, Monday, October 1.

Please submit answers to these questions either as a hard copy (typeset or handwritten are OK) or by email to terescoj AT strose.edu by the start of class. Please use a clear subject line when submitting by email (e.g., CSC 433 Lecture Assignment 9, Joe Student). We will discuss these questions at the start of class, so no late submissions are accepted.

1. Extend the state diagram from the notes that recognizes base 10 signed integers to recognize these other kinds of integer literals:
   • octal constants, which begin with a 0
   • hexadecimal constants, which begin with 0x
   • e-notation constants, which consist of a number followed by e, followed by a number

   Your diagram should have final states labeled as the different kinds of integer literals, e.g., octal-int, hex-int, e-int. (6 points)

2. (10 points) Extend the front lexical analysis code from the examples area as follows:
   • recognize floating point constants (you may assume this consists of a series of 1 or more digits, followed by a decimal point, followed by 0 or more digits),
   • recognize a semicolon token,
   • Allow underscore characters in identifiers.

Examples

• front
• recdescent