COMP313A Programming Languages

1
COMP313A Programming Languages

• Introduction

2
More Housekeeping Stuff

• Reading Material
• Textbook
• Programming Languages Principles and Practice by
  Kenneth C. Louden, PWD Publishing Company, 2003
• Course Website
• Lectures are available on the course website
  before the lecture
• Assignments will be available on the course
  website
• As much as is practical this will be a paper free
  course
• Journals e.g. ACM Transactions on Programming
  Languages and

3
More Housekeeping Stuff

• Read the Course Outline
• www.cs.waikato.ac.nz/Teaching
• www.cs.waikato.ac.nz/mjeff/COMP313A
• Check the Course Web Site regularly
• Read your email regularly
• If you send me an email question and dont want
  the reply to go to the rest of class state so
  explicitly.

4
Course Motivation

• Why are programming languages the way they are?
• How are particular language features
  implemented/supported?

5
Course Motivation cont

• understand the underlying ideas of the main
  programming paradigms
• know more about the huge variety of programming
  languages that are available nowadays
• understand how the syntax and semantics of
  languages can be defined precisely.
• know how important features are supported in
  several modern programming languages.
• have a deeper understanding of the history and
  rationale behind languages like C.

6
Lecture Outline

• Overview and History
• Syntax and Parsing
• Data Types
• Control Structures ???
• Functional Languages Issues
• Logic Programming
• Object-Oriented Language Issues

7
Programming languages you have used
Programming languages youve heard of
8
Why Programming languages?
9
What is a programming language?

• From Louden (page 3)
• A programming language is a notational system for
  describing computation in machine-readable and
  human-readable form.

10
What are programming languages

• Computation
• Anything that a computer can do
• i.e. anything that is computable (by a Turing
  Machine)
• Most programming languages are Turing Complete.
• To be useful a programming language must
  interface to all the hardware devices and
  software packages that we need to use.

11
What are programming languages

• Machine-readable
• The language must have a fixed syntax so that
  machine (computer) can read/parse programs.
• The language must have a fixed semantics so the
  computer knows what a program means and can
  execute it.

12
What are programming languages

• Human-readable
• Or preferably, human understandable
• Much harder for larger programs
• The main challenge is controlling complexity
• main tool abstraction
• The extent to which a programming language
  supports/enforces abstraction is an important
  issue

13
What are programming languages

• The human-computer semantic gap
• Human
• Interested in modelling the real world
• More interested in what computer should do than
  how
• Computer
• Only data it can manipulate is sequences of zeros
  and ones.
• Understands low-level how instructions.

14
What are programming languages

• High-level languages bridge the human-computer
  semantic gap by providing a higher level notation
  that can still be executed by computer

15
Language Implementation

• Language definition
• syntax, semantics
• Language translation