Clean Architecture: A Craftsman's Guide to Software Structure and Design (Robert C. Martin Series)

Getting software right is hard. It takes knowledge and skills that most young programmers haven’t yet acquired. It requires thought and insight that most programmers don’t take the time to develop. It requires a level of discipline and dedication that most programmers never dreamed they’d need. Mostly, it takes a passion for the craft and the desir

If you give me a program that works perfectly but is impossible to change, then it won’t work when the requirements change, and I won’t be able to make it work. Therefore the program will become useless. • If you give me a program that does not work but is easy to change, then I can make it work, and keep it working as requirements change. Therefor

The first value of software is its behavior. Programmers are hired to make machines behave in a way that makes or saves money for the stakeholders.

Every software system provides two different values to the stakeholders: behavior and structure. Software developers are responsible for ensuring that both those values remain high. Unfortunately, they often focus on one to the exclusion of the other. Even more unfortunately, they often focus on the lesser of the two values, leaving the software sy

A foundational notion of l-calculus is immutability—that is, the notion that the values of symbols do not change. This effectively means that a functional language has no assignment statement. Most functional languages do, in fact, have some means to alter the value of a variable, but only under very strict discipline.

Dijkstra once said, “Testing shows the presence, not the absence, of bugs.” In other words, a program can be proven incorrect by a test, but it cannot be proven correct. All that tests can do, after sufficient testing effort, is allow us to deem a program to be correct enough for our purposes.

The second value of software has to do with the word “software”—a compound word composed of “soft” and “ware.” The word “ware” means “product”; the word “soft”… Well, that’s where the second value lies.

Object-oriented programming imposes discipline on indirect transfer of control.

“A way to model the real world.” This is an evasive answer at best. What does “modeling the real world” actually mean, and why is it something we would want to do? Perhaps this statement is intended to imply that OO makes software easier to understand because it has a closer relationship to the real world—but even that statement is evasive and too

Notice the pattern that I’ve quite deliberately set up in introducing these three programming paradigms: Each of the paradigms removes capabilities from the programmer. None of them adds new capabilities. Each imposes some kind of extra discipline that is negative in its intent. The paradigms tell us what not to do, more than they tell us what to d