Computer Science 433
Programming Languages

Fall 2014, The College of Saint Rose

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Agenda

• Announcements
• Program/Problem Set 1: Unix Commands [HTML] [PDF] due tonight
  • questions about using Unix and/or transferring files?
• No new problem set yet - those who are less familiar with C and Unix might want to check out the labs from the CSC 381 course.
• Syntax and Semantics
  • describing syntax
  • language recognizers and generators
  • grammars
  • parse trees

Lecture 3 Assignment

Due at the start of class, Monday, September 8.

Please submit answers to these questions in Submission Box under "LA3" or in hard copy by the start of our next class. We will discuss these questions at the start of class, so no late submissions are accepted. Please be sure that your name is clearly indicated in all submissions.

The readings for next class are Sebesta Chapter 3.

Given this grammar:

<assign> => <var> = <expr>
   <var> => A | B | C | D
  <expr> => <var> + <expr>
          | <var> * <expr>
          | ( <expr> )
          | <var>

show both leftmost and rightmost derivations for the following sentences. If a sentence is in the language (not all are), just show the derivation up to the point that you can no longer proceed. (3 points each)

• A = A * ( B + ( C * A ) )
• B = B * ( (D) + C )
• C = A + B + C * D + A

Terminology

• syntax
• semantics
• language definition
• sentence
• language
• lexeme
• token
• language recognizer
• accepted, rejected strings
• syntax analysis
• language generator
• grammar
• context-free grammar
• regular grammar
• Backus-Naur Form (BNF)
• production
• abstraction
• definition
• nonterminal symbols
• terminal symbols
• left-hand side (LHS) and right-hand side (RHS) of a rule
• derivation
• start symbol
• sentential form
• leftmost (or rightmost) derivation
• parse tree
• ambiguous/unambiguous grammars
• associativity