programming language design and implemenation
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PRESENTATION ON TOPIC :->
PROGRAMMING LANGUAGES – DESIGN AND
IMPLEMENATION
Programming Languages :Language Design IssuesWhy study programming languages ?
A short history of programming languages
Impact of programming languagesRole of programming languagesProgramming enviornment
1.Why study ProgrammingLanguage Concepts?
Increased capacity to express programming concepts
Improved background for choosing appropriate languages
Increased ability to learn new languagesUnderstanding the significance of
implementation .
Why study programming languages
To improve your ability to develop effective algorithms .
To improve your use of existing programming languages .
To increase your vocabulary of useful programming constructs .
Why study programming languages
To allow a better choice of programming language
To make it easier to learn a new language
To make it easier to design a new language
Numerically based languages
Computing mathematical expressions
FORTRAN, Algol, Pascal, PL/1, BASIC, C, C++
Business languages
COBOL (Common Business Oriented Language) English-like notation
Artificial intelligence languages
Tree search; Rule-based paradigm
LISP (LISt Processing)
PROLOG (PROgramming in LOGic)
System languages
C, C++
Script languages: AWK, Perl, TCL/TK
Web programming: HTML, XML, Java,
Microsoft *.NET family
1.Batch enviornment (batches of files)
2.Interactive enviornment (time sharing)
Effects on language design
File I/O in batch processing
Error handling in batch processing
Time constraints in interactive processing
1.Interactive processing
2.Embedded system environments
Effects on language design
No need for time sharing
Good interactive graphics
Non-standard I/O devices for embedded systems
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
3.Impact of programming paradigmsWhat is programming language .
Language paradigms .
Problem solving .
Software design .
Attributes of a good languageClarity,simplicity,unityOrthogonalityNaturalness for the applicationSupport for abstractionEase of program verificationProgramming environmentPortability of programsCost of use 1.cost of program execution
2.cost of program translation
3.cost of program creation,testing,use.
1.WHAT IS PROGRAMMING LANGUAGE?
Programming languages are essentially carefully designed notations .They are used to specify ,organize, and reason about the various aspects of problem solving. The designers of programming language have twin goals:
Making computing convenient.Making efficient use of computing machines.
2.Language paradigms
Imperative / procedural languages
Applicative / functional languages
Rule-based / declarative languages
Object-oriented languages
Statement oriented languages that change machine state
EX : (C, Pascal, FORTRAN, COBOL)
Computation: a sequence of machine states (contents of memory)
Syntax: S1, S2, S3, ... where S1, S2, … are statements
Programming consists of building the function that computes the answer
EX: (ML, LISP)
Computation: Function composition is major operation
Syntax: F1(F2(F3(X))) where F1,F2,F3 are functions & X is data .
Computation: Actions are specified by rules that check for the presence of certain enabling conditions. EX:(Prolog)
The order of execution is determined by the enabling conditions, not by the order of the statements.
Syntax: Condition Action
Imperative languages that merge applicative design with imperative statements
EX:(Java, C++, Smalltalk)
Syntax: Set of objects (classes) containing data (imperative concepts) and methods (applicative concepts)
3.Problem solving Defining the systemAnalyzing the system definedDetailed system specificationDesign the systemImplement the designTesting and debuggingvalidation
4.Software design Software design sits at crossroads of all the
computers : hardware and software engineering and programming, human factors research , ergonomics .
It Is the study of intersection of human , machine ,and the various interfaces- physical ,sensory ,psychological -that connect them .
A designer studies the following aspects of a programming language or paradigm:
Support for abstraction.Parameters and parameter
transmission. Exceptions and exception handling.Support for static and dynamic storage
management.
The need for standards - to increase portability of programs
Problem: When to standardize a language?
If too late - many incompatible versions
If too early - no experience with language
Problem: What happens with the software developed before the standardization?
Ideally, new standards have to be compatible with older standards.
I18N issue - How to specify languages useful in a global economy?
• What character codes to use?
• Collating sequences? - How do you alphabetize various languages?
• Dates? - What date is 10/12/01? 10-12-01? 12.10.01 ?Is it a date in October or December?
• Time? - How do you handle
• time zones,
• summer time in Europe,
• daylight savings time in US,
• Southern hemisphere is 6 months out of phase with northern hemisphere,
• the date to change from summer to standard time is not consistent.
• Currency? - How to handle dollars, pounds, marks, francs, euros, etc.
Programming environment:
the environment in which programs are created and tested.
Separate compilation
Separate execution
Testing
Debugging
Effects on language design :->
Modular organization
Local/global variables
Libraries
Process control languages
Scripting languages
• Usually interpreted,
• Able to process programs and data files
• Specify a sequence of operations on program and data files.
Awk, Perl, Tcl/Tk
•Language design must:
Allow program solution to match problem structure
Allow for world-wide use
Be easy to prove correctness of solutions