Multi-Paradigm Programming and Scripting

Why Multi-Paradigm Programming and Scripting?:

• Universal programming constructs (invariant of language), their functions, uses and how different paradigms/languages employ them.
• Improved background for choosing appropriate languages:

• Analyse and evaluate the strengths and weaknesses of various programming languages for use in solving particular problems.

Content:

Programming Constructs:

• The compilation process
• Data types (strongly-typed, weakly-typed)
• Pointers
• Variables and Invariants
• Conditionals (Selection)
• Sequence
• Repetition
• Routines
• Concurrency

Programming Paradigms & Languages:

• Abstraction (machine to very-high-level)
• Mark-up
• Imperative & Declarative
• Procedural
• Parallel & Concurrent
• Functional
• Event-Driven
• Multi-Paradigm Languages
• Interpreted Languages
• Comparison of all to Object Oriented Paradigm

Scripting:

• Interpreters and system commands
• Shell Scripting (Linux/UNIX)
• PowerShell Scripting (Windows)
• System Programming & Scripting

Applications of Shell Scripting:

• Job Control
• Glue Code / Wrappers
• Automating Tasks
• Data Processing / Transformation
• System uses
• I/O tasks and functions

Examples from Introduction to Programming Using Python 3

http://www.cs.armstrong.edu/liang/py/ExampleByChapters.html

C++ tutorial

http://www.cplusplus.com/doc/tutorial/program_structure/

Phases of Compilation

C++ Inheritance

https://www.w3schools.com/cpp/cpp_inheritance.asp

https://www.tutorialspoint.com/cplusplus/cpp_interfaces.htm

Difference Between Static and Dynamic Binding

https://techdifferences.com/difference-between-static-and-dynamic-binding.html

Reflection

A programming language that supports reflection allows its programs to have runtime access to their types and structure and to be able to dynamically modify their behavior

• The types and structure of a program are called metadata

• The process of a program examining its metadata is called introspection

• Interceding in the execution of a program is called intercession

Uses of reflection for software tools:

• Class browsers need to enumerate the classes of a program
• Visual IDEs use type information to assist the developer in building type correct code
• Debuggers need to examine private fields and methods of classes
• Test systems need to know all of the methods of a class

Downsides of Reflection:

• Performance costs
• Exposes private fields and methods
• Voids the advantages of early type checking
• Some reflection code may not run under a security manager, making code nonportable

Reflection in Java

• Limited support from java.lang.Class

• Java runtime instantiates an instance of Class for each object in the program

• The getClass method of Class returns the Class object of an object

float[] totals = new float[100];

Class fltlist = totals.getClass();

Class stg = "hello".getClass();

• If there is no object, use class field:

Class stg = String.class;

• Class has four useful methods:

getMethod searches for a specific public method of a class

getMethods returns an array of all public methods of a class

getDeclaredMethod searches for a specific method of a class

getDeclaredMethods returns an array of all methods of a class

The Method class defines the invoke method, which is used to execute the method found by getMethod