Sometimes a short thought can bring amazing ideas.
There are some great quotes I’ve been collecting.
I use them as inspiration or motto for some articles.
Software Design
There are only two hard things in Computer Science: cache invalidation and naming things.
Phil Karlton
Make illegal states unrepresentable.
Yaron Minsky
First make the change easy (warning: this might be hard), then make the easy change.
Kent Beck
Object-oriented programming languages support encapsulation, thereby improving the ability of software to be reused, refined, tested, maintained, and extended. The full benefit of this support can only be realized if encapsulation is maximized during the design process.
Rebecca Wirfs-Brock
Science is what we understand well enough to explain to a computer. Art is everything else we do.
Donald Knuth
The biggest issue on software teams is making sure everyone understands what everyone else is doing.
Martin Fowler
Object thinking focuses our attention on the problem space rather than the solution space.
David West
We comfort ourselves with the belief that if the customers had just been happy with what they said they needed, the design would have been fine. It’s the customer’s fault for changing the requirements on us.
Robert Martin
There is an art to knowing where things should be checked and making sure that the program fails fast if you make a mistake. That kind of choosing is part of the art of simplification.
Ward Cunningham
You cannot teach beginners top-down programming, because they don't know which end is up.
Tony Hoare
Writing a class without its contract would be similar to producing an engineering component (electrical circuit, VLSI (Very Large Scale Integration) chip, bridge, engine...) without a spec. No professional engineer would even consider the idea.
Bertrand Meyer
A cache with a bad policy is another name for a memory leak.
Rico Mariani
The value of a prototype is in the education it gives you, not in the code itself.
Alan Cooper
When someone says, "I want a programming language in which I need only say what I want done," give him a lollipop.
Alan Perlis
Simple things should be simple, complex things should be possible.
Alan Kay
Code Smell 31 - Accidental Methods on Business Objects
Maxi Contieri ・ Nov 22 '20
Object-oriented programming increases the value of these metrics by managing this complexity. The most effective tool available for dealing with complexity is abstraction. Many types of abstraction can be used, but encapsulation is the main form of abstraction by which complexity is managed in object-oriented programming.
Rebecca Wirfs-Brock
Code Smell 21 - Anonymous Functions Abusers
Maxi Contieri ・ Nov 10 '20
Make it correct, make it clear, make it concise, make it fast. In that order.
Wes Dyer
Indeed, the woes of Software Engineering are not due to lack of tools, or proper management, but largely due to lack of sufficient technical competence.
Niklaus Wirth
Hackers are arrogant geek romantics. They lack the attentive spirit of inquiry.
Bruce Sterling
If someone claims to have the perfect programming language, he is either a fool or a salesman or both.
Bjarne Stroustrup
Thinking is not the ability to manipulate language; it's the ability to manipulate concepts.
Leslie Lamport
Programming is not about typing, it's about thinking.
Rich Hickey
There’s nothing more permanent than a temporary hack.
Kyle Simpson
The purpose of software engineering is to control complexity, not to create it.
Pamela Zave
The purpose of computing is insight, not numbers.
Richard Hamming
The trick is to fix the problem you have, rather than the problem you want.
Bram Cohen
Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification.
Bertrand Meyer
Software and cathedrals are much the same. First we build them, then we pray.
Sam Redwine
Software is a gas; it expands to fill its container.
Nathan Myhrvold
Code Smell 43 - Concrete Classes Subclassified
Maxi Contieri ・ Dec 5 '20
I can’t be as confident about computer science as I can about biology. Biology easily has 500 years of exciting problems to work on. It’s at that level
Donald Knuth
I couldn't resist the temptation to put in a null reference, simply because it was so easy to implement. This has led to innumerable errors, vulnerabilities, and system crashes, which have probably caused a billion dollars of pain and damage in the last forty years.
Tony Hoare
Simplicity is prerequisite for reliability.
Edsger W. Dijkstra
Types are essentially assertions about a program. And I think it’s valuable to have things be as absolutely simple as possible, including not even saying what the types are.
Dan Ingalls
Before software can be reusable it first has to be usable.
Ralph Johnson
Most software today is very much like an Egyptian pyramid with millions of bricks piled on top of each other, with no structural integrity, but just done by brute force and thousands of slaves.
Alan Kay
The Scrum idea of a separated Scrum Master is good for Scrum, but not appropriate for most projects. Good development requires not just talkers but doers.
Bertrand Meyer
Premature optimization is the root of all evil
Donald Knuth
Code Smell 20 - Premature Optimization
Maxi Contieri ・ Nov 8 '20
When in doubt, use brute force.
Ken Thompson
Any problem in computer science can be solved with another level of indirection.
David Wheeler
Computer science is not about machines, in the same way that astronomy is not about telescopes. There is an essential unity of mathematics and computer science.
Michael R. Fellows
Computer scientists have so far worked on developing powerful programming languages that make it possible to solve the technical problems of computation. Little effort has gone toward devising the languages of interaction.
Don Norman
Developers are drawn to complexity like moths to a flame, frequently with the same result.
Neal Ford
In programming, the hard part isn't solving problems, but deciding what problems to solve.
Paul Graham
Walking on water and developing software from a specification are easy if both are frozen.
Edward V Berard
The Diagram is Not the Model. The model is not the diagram. It is an abstraction, a set of concepts and relationships between them.
Eric Evans
The best performance improvement is the transition from the nonworking state to the working state.
J. Osterhout
I’m not a great programmer; I’m just a good programmer with great habits.
Kent Beck
I can’t be as confident about computer science as I can about biology. Biology easily has 500 years of exciting problems to work on. It’s at that level.
Donald Knuth
Architecture is the tension between coupling and cohesion.
Neal Ford
The role of a trainer or consultant is to empower the customer, not to make himself indispensable.
Bertrand Meyer
It is very hard to predict, especially the future.
Niels Bohr
A computer lets you make more mistakes faster than any other invention with the possible exceptions of handguns and Tequila.
Mitch Ratcliffe
Photo by Shahadat Rahman on Unsplash
Programming Languages
Many people tend to look at programming styles and languages like religions: if you belong to one, you cannot belong to others. But this analogy is another fallacy.
Niklaus Wirth
If debugging is the process of removing software bugs, then programming must be the process of putting them in.
Edsger Dijkstra
Code Smell 36 - Switch/case/elseif/else/if statements
Maxi Contieri ・ Nov 28 '20
More good code has been written in languages denounced as “bad” than in languages proclaimed “wonderful” — much more.
Bjarne Stroustrup
Computers are good at following instructions, but not at reading your mind.
Donald Knuth
Sun Microsystems had the right people to make Java into a first-class language, and I believe it was the Sun marketing people who rushed the thing out before it should have gotten out.
Alan Kay
There are only two kinds of languages: the ones people complain about and the ones nobody uses.
Bjarne Stroustrup
Photo by You X Ventures on Unsplash
Planning / Management
The cost of adding a feature isn’t just the time it takes to code it. The cost also includes the addition of an obstacle to future expansion. The trick is to pick the features that don’t fight each other.
John Carmack
Einstein repeatedly argued that there must be simplified explanations of nature, because God is not capricious or arbitrary. No such faith comforts the software engineer.
Fred Brooks
Subclasses shouldn’t always share all characteristics of their parent class but will do so with inheritance. This can make a program’s design less flexible. It also introduces the possibility of calling methods on subclasses that don’t make sense or that cause errors because the methods don’t apply to the subclass.
Steve Klabnik
Programmers are as emotional and irrational as normal people.
Douglas Crockford
There is nothing so useless as doing efficiently that which should not be done at all.
Peter Drucker
You can mass-produce hardware; you cannot mass-produce software; you cannot mass-produce the human mind.
Michio Kaku
Any organization that designs a system (defined broadly) will produce a design whose structure is a copy of the organization’s communication structure.
Melvin Conway
Optimism is an occupational hazard of programming: feedback is the treatment.
Kent Beck
Photo by Bench Accounting on Unsplash
Clean Code
Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live.
John Woods
Successful software always gets changed.
Fred Brooks
Thinking about my experience of modifying code, I see that I spend much more time reading the existing code than I do writing new code. If I want to make my code cheap, therefore, I should make it easy to read.
Kent Beck
If you have to spend effort looking at a fragment of code and figuring out what it’s doing, then you should extract it into a function and name the function after the what.
Martin Fowler
The nice thing about standards is that there are so many to choose from.
Andrew S. Tannenbaum
Code Smell 48 - Code Without Standards
Maxi Contieri ・ Dec 10 '20
It’s harder to read code than to write it.
Joel Spolsky
Complexity kills. It sucks the life out of developers, it makes products difficult to plan, build and test, it introduces security challenges, and it causes end-user and administrator frustration.
Ray Ozzie
It is not the language that makes programs appear simple. It is the programmer that make the language appear simple.
Robert Martin
We have to stop optimizing for programmers and start optimizing for users.
Jeff Atwood
If you have three pet dogs, give them names. If you have 10,000 head of cattle, don't bother. Nowadays, the idea of giving a name to every file on your computer is ridiculous.
David Gelernter
Error handling is important, but if it obscures logic, it’s wrong.
Robert Martin
When debugging, novices insert corrective code; experts remove defective code.
Richard Pattis
A good programmer is someone who always looks both ways before crossing a one-way street.
Doug Linder
The cleaner and nicer the program, the faster it's going to run. And if it doesn't, it'll be easy to make it fast.
Joshua Bloch
Writing software as if we are the only person that ever has to comprehend it is one of the biggest mistakes and false assumptions that can be made.
Karolina Szczur
The best smells are something that's easy to spot and most of time lead you to really interesting problems. Data classes (classes with all data and no behavior) are good examples of this. You look at them and ask yourself what behavior should be in this class.
Martin Fowler
It's not at all important to get it right the first time. It's vitally important to get it right the last time.
Andrew Hunt and David Thomas
Prolific developers don’t always write a lot of code, instead they solve a lot of problems. The two things are not the same.
J. Chambers
Programs are meant to be read by humans and only incidentally for computers to execute.
Donald Knuth
A programming language is low level when its programs require attention to the irrelevant.
Alan Perlis
This will surprise some of your readers, but my primary interest is not with computer security. I am primarily interested in writing software that works as intended.
Wietse Venema
You will fall to ruin because you believe that exceptions to the rule make new rules.
Pierce Brown
Code Smell 26 - Exceptions Polluting
Maxi Contieri ・ Nov 16 '20
Every time you write a comment, you should grimace and feel the failure of your ability of expression
Robert Martin
Simplicity is the soul of efficiency.
Austin Freeman
Programming can be fun, so can cryptography; however they should not be combined.
Kreitzberg & Shneiderman
So much complexity in software comes from trying to make one thing do two things.
Ryan Singer
Deleted code is debugged code.
Jeff Sickel
Any fool can write code that a computer can understand. Good programmers write code that humans can understand.
Martin Fowler
The ratio of time spent reading (code) versus writing is well over 10 to 1 ... (therefore) making it easy to read makes it easier to write.
Robert Martin
Any code of your own that you haven’t looked at for six or more months might as well have been written by someone else.
Eagleson’s Law
One day my daughter came in, looked over my shoulder at some Perl 4 code, and said, "What is that, swearing?"
Larry Wall
Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.
Brian Kernighan
If you say “I told you so”, you are the one who has failed. Because you knew, but did not manage to stop the train wreck.
Robert Martin
Some people, when confronted with a problem, think “I know, I’ll use regular expressions.” Now they have two problems.
Jamie Zawinski
Don’t comment bad code — rewrite it.
Brian Kernighan
Code is like humor. When you have to explain it, it’s bad.
Cory House
A long descriptive name is better than a short enigmatic name. A long descriptive name is better than a long descriptive comment.
Robert Martin
Talk is cheap. Show me the code.
Linus Torvalds
Photo by Raquel Martínez on Unsplash
Software Quality
Legacy code is code without tests.
Michael Feathers
Somebody will say they have a program that’s verified and it’s only verified because it met its specification according to some verifier. But the verifier might have bugs in it. The specifications might have bugs in them
Donald Knuth
The first 90 percent of the code accounts for the first 90 percent of the development time. The remaining 10 percent of the code accounts for the other 90 percent of the development time
Tom Cargill
One man's crappy software is another man's full time job.
Jessica Gaston
Code Smell 42 - Warnings/Strict Mode Off
Maxi Contieri ・ Dec 4 '20
The pesticide paradox. Every method you use to prevent or find bugs leaves a residue of subtler bugs against which those methods are ineffective.
Boris Beizer
I try to think mostly in terms of preconditions, and checking things in the constructor and the beginning of a function.
Brad Fitzpatrick
Good software, like wine, takes time.
Joel Spolsky
Pasting code from the internet into production code is like chewing gum found in the street.
Mike Johnson
Discovering the unexpected is more important than confirming the known.
George E. P. Box
Pay attention to zeros. If there is a zero, someone will divide by it.
Cem Kaner
Beta testing is a symptom of weak testing practices and poor communication with customers
Kent Beck
Beware of bugs in the above code; I have only proved it correct, not tried it.
Donald Knuth
The key to building a great product is building a great team first. To me, great teams aren’t bound by roles, but they’re driven by moving forward.
Alan Page
With tests, we can change the behavior of our code quickly and verifiably.
Without them, we really don’t know if our code is getting better or worse.”
Michael Feathers
How to Squeeze Test Driven Development on Legacy Systems
Maxi Contieri ・ Nov 26 '20
Correctness is clearly the prime quality. If a system does not do what it is supposed to do, then everything else about it matters little.
Bertrand Meyer
A Perl program is correct if it gets the job done before your boss fires you.
Larry Wall
Code Smell 41 - Regular Expression Abusers
Maxi Contieri ・ Dec 3 '20
As the Tests get more Specific, the Code gets more Generic.
Robert Martin
Software testing is not only ensuring absence of bugs but also ensuring presence of value.
Amit Kalantri
Quality is free, but only to those who are willing to pay heavily for it.
DeMarco and Lister
Developer testing is an important step towards accountability. It gives developers a way to demonstrate the quality of the software they produce.
Kent Beck
Nothing makes a system more flexible than a suite of tests.
Robert Martin
As a rule, software systems do not work well until they have been used, and have failed repeatedly, in real applications.
David Parnas
There are two ways to write error-free programs; only the third one works.
Alan J. Perlis
Photo by Kelvyn Ornettte Sol Marte on Unsplash
Refactoring
Whenever I have to think to understand what the code is doing, I ask myself if I can refactor the code to make that understanding more immediately apparent.
Martin Fowler
Photo by National Cancer Institute on Unsplash
Object Oriented
Let there be no doubt that object-oriented design is fundamentally different than traditional structured design approaches: it requires different ways of thinking about decomposition, and it produces software architectures that are largely outside the realm of the structured design culture.
Grady Booch
I invented the term ‘object oriented’, and C++ was not what I had in mind.
Alan Kay
Part of the objective of this series of articles is to generate spaces for debate and discussion on software design.
We look forward to comments and suggestions on this article.
Original Thread on Twitter