1. Principles of Programming Languages

2. The Structure And Operation Of A Computer
A computer is an integrated set of algorithms and data structures capable of storing and executing programs.
Hardware computer
Virtual computer

3. The von Neumann Architecture

4. Major Components of a Computer
Data
Various kinds of elementary and structured data.
Primitive operations
Sequence control
Controlling the sequence of primitive operations execution.
Data access
Controlling the data supplied to each execution of an operation.

5. Major Components of a Computer
Storage management
Controlling the allocation of storage for programs and data. Main memory
Main memory
Register
High-speed cache memory
External files
Operating environment
Providing mechanisms for communication with an external environment containing programs and data.

6. Operations A set of build-in primitive operations
Arithmetic operations on each built-in numeric data (+,-,*,/)
Testing various properties of data items (test for zero, positive, and negative numbers)
Accessing and modifying various parts of a data item
Controlling input-output devices
Sequence control (jumps)

7. Sequence Control There is an interpreter : Fetch the instruction
Decode instruction
Fetch designated operands
Branch to designated operation
Execute primitive operations 1 to n
Using an address register

8. Software architectures 1. Mainframe era
Batch processing (batches of files)
Interactive processing (time sharing)
 Effects on language design
File I/O in batch processing
Error handling in batch processing
Time constraints in interactive processing

9. 2. Personal computers Effects on language design
Interactive processing
Embedded system environments
   
Effects on language design
No need for time sharing
Good interactive graphics
Non-standard I/O devices for embedded systems

10. 3. Networking era (Client-server model of computing)
Server: a program that provides information
Client - a program that requests information 
Effects on language design
Interaction between the client and server programs
Active web pages, Security issues, Performance

11. LANGUAGE DEVELOPMENT Numerically based languages Business languages
Computing mathematical expressions
FORTRAN, Algol, Pascal, PL/1, BASIC, C, C++wrk
Numerically based languages
COBOL (Common Business Oriented Language) English-like notation
Business languages
Tree search; Rule-based paradigm
LISP (LISt Processing)
PROLOG (PROgramming in LOGic)
Artificial intelligence languages
System languages
Web programming
C, C++ and Script languages: AWK, Perl, TCL/TK
HTML, XML, PHP

12. LANGUAGE DESIGN ISSUES
Languages are designed to:
Languages in the earlier era were designed to run efficiently
Languages in the new era are designed to be written correctly with minimum lines of code
Data typing features in ML
Class of C++
Package of Ada
DESIGN GOALS
During 1950s--1960s - Run-time considerations
Programmers are cheap, machines expensive; Keep the machine busy
Today - program development time considerations
CPU power and memory are very cheap

13. Attributes of a good language
Conceptual integrity
Orthogonality
Naturalness for the application
Support for abstraction
Ease of program verification
Programming environment
Portability of programs
Cost of use
Cost of execution.
Cost of program translation.
Cost of program creation, testing, and use.
Cost of program maintenance.

14. Language paradigms Imperative / procedural languages
Applicative / functional languages
Rule-based / declarative languages
Object-oriented languages

15. Imperative / procedural languages
Statement oriented languages that change machine state
(C, Pascal, FORTRAN, COBOL)
Computation: a sequence of machine states (contents of memory)
Syntax: S1, S2, S3, ... where S1, S2, … are statements

16. Applicative / functional languages
Programming consists of building the function that computes the answer
Computation: Function composition is major operation (ML, LISP)
Syntax: P1(P2(P3(X)))

17. Rule-based / declarative languages
Computation: Actions are specified by rules that check for the presence of certain enabling conditions. (Prolog)
The order of execution is determined by the enabling conditions, not by the order of the statements.
Syntax: Condition  Action

18. Object-oriented languages
Imperative languages that merge applicative design with imperative statements (Java, C++, Smalltalk)
Syntax: Set of objects (classes) containing data (imperative concepts) and methods (applicative concepts)