Programming Paradigms

This is a placeholder for some terminology.

There are some ‘big’ programming paradigms that I’m familiar with. Procedural, functional, and object oriented are ones I have hands-on experience with. There’s also imperative versus declarative, and the idea of reflection, and macros, and... well. Programming languages tend to support one or more of these paradigms, and that, in turn, will affect the way in which a coder will code. Since production languages tend to be Turing complete, you can technically force any language into any paradigm. Having said that, programming languages are tools, and just like real tools, while you can force them into tasks they weren’t designed for, it’s probably better to just change tools.

Real fast, for those who aren’t programmers, Turing completeness describes a machine that can perform any calculation. You can imagine a machine that can read symbols that are printed on an infinite ribbon, and can interpret those symbols to carry out an arbitrary number of instructions, as well as modify those symbols. For practical purposes, if a programming language has an IF construct, and can read from, write to, and modify memory, it’s Turing complete.

IMPERATIVE programs are programs that can be described as a series of orders. Imperatives, if you will. PRINT a number, GOTO a line number, do this, do that. You can think of it as marching orders for the machine. Procedural and object oriented programming tends to fall in this category.

DECLARATIVE programs just describe what the program should do, but not a thing about how it should go about doing it. Functional and logical programming languages tend to enter this paradigm, as well as database languages such as SQL.

PROCEDURAL programs are the ones I am most familiar with. They have a list of commands to be followed, and procedures which can be called. C and BASIC are procedural programs, with the procedures that can be called being known as ‘functions’ in C, and ‘subroutines’ in BASIC. I think BASIC also has functions, but it’s been so long since I used it, I don’t really recall.

FUNCTIONAL programs are called that because they can be thought of as running a series of mathematically provable functions as programs. Haskell is an example here. They are noted for their lack of side effects, which is a way of saying that they don’t modify states like procedural/imperative languages do.

OBJECT ORIENTED programs have, well, objects. These objects tend to have a number of characteristics, such as encapsulation, and message passing. An object will tend to have a public interface, which is a way of passing commands to the object. This object will then have an implementation, which code outside the object doesn’t need to concern itself with. Objects often can also pass messages to each other, and act on these messages. C++ and Java are object oriented languages.

Hopefully this is clearer than the relevant Wiki pages.