TLDR: The abstraction principle in computer programming is all about reducing duplication of information in a program. It recommends using abstractions provided by the programming language or software libraries to avoid repeating code and effort. It's like using shortcuts and templates to make programming easier and more efficient.

The abstraction principle, also known as the principle of abstraction, is a fundamental concept in software engineering and programming language theory. Its goal is to minimize code duplication by utilizing abstractions provided by the programming language or software libraries. This principle can be seen as a recommendation to programmers or as a requirement of the programming language itself.

When viewed as a recommendation, the abstraction principle is often referred to as the "don't repeat yourself" (DRY) principle. It advises programmers to avoid duplicating information and effort in the software development process. By combining similar functions into one and abstracting out the varying parts, programmers can reduce redundancy and make their code more efficient.

The abstraction principle has been formulated by different authors with slight variations. Benjamin C. Pierce, in his book "Types and Programming Languages," emphasizes that each significant piece of functionality in a program should be implemented in just one place in the source code. David A. Schmidt, in "The Structure of Typed Programming Languages," states that the phrases of any semantically meaningful syntactic class may be named.

The principle has been mentioned in various books, such as "An Introduction to Programming with S-algol" by Alfred John Cole and Ronald Morrison, "Principles of Programming Languages: Design, Evaluation, and Implementation" by Bruce J. MacLennan, and "Programming and Meta-Programming in Scheme" by Jon Pearce. It also plays a central role in design patterns in object-oriented programming, where the focus is on encapsulating the concept that varies.

In recent years, the abstraction principle has been reinvented in extreme programming under the slogan "Once and Only Once." This principle emphasizes the elimination of duplicate code and the automation of repetitive tasks.

The abstraction principle has important implications in programming. It is often associated with mechanisms that facilitate abstraction, such as control abstraction through functions or subroutines, and data abstractions through type polymorphism. The quest for richer abstractions that allow less duplication in complex scenarios is a driving force in programming language research and design.

However, inexperienced programmers may be tempted to introduce excessive abstraction that is not actually used more than once. This issue is addressed by the complementary principle of "You Ain't Gonna Need It" (YAGNI) and the Keep It Simple, Stupid (KISS) principle, which emphasize the importance of simplicity and avoiding unnecessary complexity.

Following the abstraction principle may also require refactoring code, especially when revisions are made. The effort of rewriting code needs to be balanced against the potential benefits of abstraction. The rule of three, popularized by Martin Fowler, suggests that if a piece of code is copied more than twice, it should be abstracted out.

A generalization of the abstraction principle is the "Don't Repeat Yourself" (DRY) principle, which is often applied in multi-tier architectures. It recommends relying on automated tools, such as code generators and data transformations, to avoid repetition.

In addition to optimizing code, the concept of abstraction level in programming also applies to hardware programming interfaces. It refers to the interfaces between hardware communication layers, where the level of abstraction often corresponds to the interface. For example, the level of abstraction changes from operating system commands to register and circuit level calls and commands.

In summary, the abstraction principle in computer programming is all about reducing duplication of information and effort. It encourages programmers to use abstractions provided by the programming language or software libraries to make their code more efficient and maintainable. By avoiding repetition and automating repetitive tasks, programmers can improve the quality of their software.

Related Links:

• Software Engineering
• Programming Language Theory
• Object-Oriented Programming