Pragmatic Programmer
- Tips
- Care About Your Craft
- Why spend your life developing software unless you care about doing it well?
- Think! About Your Work
- Turn off the autopilot and take control. Constantly critique and appraise your work.
- Provide Options, Don't Make Lame Excuses
- Instead of excuses, provide options. Don't say it can't be done: explain what can be done.
- Don't Live With Broken Windows
- Fix bad designs, wrong decisions, and poor code when you see them.
- Be a Catalyst for Change
- You can't force change on people. Instead, show them how the future might be and help them participate in creating it.
- Remember the Big Picture
- Don't get so engrossed in the details that you forget to check what's happening around you.
- Make Quality a Requirements Issue
- Involve your users in determining the project's real quality requirements.
- Invest Regularly in Your Knowledge Portfolio
- Critically Analyze What You Read and Hear
- Don’t be swayed by vendors, media hype, or dogma. Analyze information in terms of you and your project.
- It’s Both What You Say and the Way You Say It
- There’s no point in having great ideas if you don’t communicate them effectively.
- DRY–Don’t Repeat Yourself
- Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.
- Make It Easy to Reuse
- If it’s easy to reuse, people will. Create an environment that supports reuse.
- Eliminate Effects Between Unrelated Things
- Design components that are self-contained. independent, and have a single, well-defined purpose.
- There Are No Final Decisions
- No decision is cast in stone. Instead, consider each as being written in the sand at the beach, and plan for change.
- Use Tracer Bullets to Find the Target
- Tracer bullets let you home in on your target by trying things and seeing how close they land.
- Prototype to Learn
- Prototyping is a learning experience. Its value lies not in the code you produce, but in the lessons you learn.
- Program Close to the Problem Domain
- Design and code in your user’s language.
- Estimate to Avoid Surprises before you start. You’ll spot potential problems up front.
- Iterate the Schedule with the Code
- Use experience you gain as you implement to refine the project time scales.
- Keep Knowledge in Plain Text
- Plain text won’t become obsolete. It helps leverage your work and simplifies debugging and testing.
- Use the Power of Command Shells
- Use the shell when graphical user interfaces don’t cut it.
- Use a Single Editor Well
- The editor should be an extension of your hand; make sure your editor is configurable, extensible, and programmable.
- Always Use Source Code Control
- Source code control is a time machine for your work—you can go back.
- Fix the Problem, Not the Blame
- It doesn’t really matter whether the bug is your fault or some one else’s—it is still your problem, and it still needs to be fixed.
- Don’t Panic When Debugging
- Take a deep breath and THINK! about what could be causing the bug.
- “select” Isn’t Broken.
- It is rare to find a bug in the OS or the compiler, or even a third-party product or library. The bug is most likely in the application.
- Don’t Assume It—Prove It
- Prove your assumptions in the actual environment– with real data and boundary conditions.
- Learn a Text Manipulation Language.
- You spend a large part of each day working with text. Why not have the computer do some of it for you?
- Write Code That Writes Code
- Code generators increase your productivity and help avoid duplication.
- You Can’t Write Perfect Software
- Software can’t be perfect. Protect your code and users from the inevitable errors.
- Design with Contracts
- Use contracts to document and verify that code does no more and no less than it claims to do.
- Crash Early
- A dead program normally does a lot less damage than a crippled one.
- Use Assertions to Prevent the Impossible
- Assertions validate your assumptions. Use them to protect your code from an uncertain world.
- Use Exceptions for Exceptional Problems
- Exceptions can suffer from all the readability and maintain ability problems of classic spaghetti code. Reserve exceptions for exceptional things.
- Finish What You Start
- Where possible, the routine or object that allocates a resource should be responsible for deallocating it.
- Minimize Coupling Between Modules
- Avoid coupling by writing “shy” code and applying the Law of Demeter.
- Configure, Don’t Integrate
- Implement technology choices for an application as configuration options, not through integration or engineering.
- Put Abstractions in Code, Details in Metadata
- Program for the general case, and put the specifics outside the compiled code base.
- Analyze Workflow to Improve Concurrency
- Exploit concurrency in your user’s workflow.
- Design Using Services
- Design in terms of services—independent, concurrent objects behind well-defined, consistent interfaces.
- Always Design for Concurrency
- Allow for concurrency, and you’ll design cleaner interfaces with fewer assumptions.
- Separate Views from Models
- Gain flexibility at low cost by designing your application in terms of models and views.
- Use Blackboards to Coordinate Workflow
- Use blackboards to coordinate disparate facts and agents, while maintaining independence and isolation among participants.
- Don’t Program by Coincidence
- Rely only on reliable things. Beware of accidental complexity, and don’t confuse a happy coincidence with a purposeful plan.
- Estimate the Order of Your Algorithms
- Get a feel for how long things are likely to take before you write code.
- Test Your Estimates
- Mathematical analysis of algorithms doesn’t tell you every thing. Try timing your code in its target environment.
- Refactor Early, Refactor Often
- Just as you might weed and rearrange a garden, rewrite, rework, and re-architect code when it needs it. Fix the root of the problem.
- Design to Test
- Start thinking about testing before you write a line of code.
- Test Your Software, or Your Users Will
- Test ruthlessly. Don’t make your users find bugs for you.
- Don’t Use Wizard Code You Don’t Understand
- Wizards can generate reams of code. Make sure you understand all of it before you incorporate it into your project.
- Don’t Gather Requirements–Dig for Them
- Requirements rarely lie on the surface. They’re buried deep beneath layers of assumptions, misconceptions, and politics.
- Work with a User to Think Like a User
- It’s the best way to gain insight into how the system will really be used.
- Abstractions Live Longer than Details
- Invest in the abstraction, not the implementation. Abstractions can survive the barrage of changes from different implementations and new technologies.
- Use a Project Glossary
- Create and maintain a single source of all the specific terms and vocabulary for a project.
- Don’t Think Outside the Box–Find the Box
- When faced with an impossible problem, identify the real constraints. Ask yourself: “Does it have to be done this way? Does it have to be done at all?”
- Start When You’re Ready.
- You’ve been building experience all your life. Don’t ignore niggling doubts.
- Some Things Are Better Done than Described
- Don’t fall into the specification spiral—at some point you need to start coding.
- Don’t Be a Slave to Formal Methods.
- Don’t blindly adopt any technique without putting it into the context of your development practices and capabilities.
- Costly Tools Don’t Produce Better Designs
- Beware of vendor hype, industry dogma, and the aura of the price tag. Judge tools on their merits.
- Organize Teams Around Functionality
- Don’t separate designers from coders, testers from data modelers. Build teams the way you build code.
- Don’t Use Manual Procedures
- A shell script or batch file will execute the same instructions, in the same order, time after time.
- Test Early. Test Often. Test Automatically
- Tests that run with every build are much more effective than test plans that sit on a shelf.
- Coding Ain’t Done ‘Til All the Tests Run
- Use Saboteurs to Test Your Testing
- Introduce bugs on purpose in a separate copy of the source to verify that testing will catch them.
- Test State Coverage, Not Code Coverage
- Identify and test significant program states. Just testing lines of code isn’t enough.
- Find Bugs Once
- Once a human tester finds a bug, it should be the last time a human tester finds that bug. Automatic tests should check for it from then on.
- English is Just a Programming Language
- Write documents as you would write code: honor the DRY principle, use metadata, MVC, automatic generation, and so on.
- Build Documentation In, Don’t Bolt It On
- Documentation created separately from code is less likely to be correct and up to date.
- Gently Exceed Your Users’ Expectations
- Come to understand your users’ expectations, then deliver just that little bit more.
- Sign Your Work
- Craftsmen of an earlier age were proud to sign their work. You should be, too.
- Checklists
- Languages To Learn
- Tired of C, C++, and Java? Try CLOS, Dylan, Eiffel, Objective C, Prolog, Smalltalk, or TOM. Each of these languages has different capabilities and a different “flavor." Try a small project at home using one or more of them.
- The WISDOM Acrostic
- What do you want them to learn?
- What is their interest in what you’ve got to say?
- How sophisticated are they?
- How much detail do they want?
- Whom do you want to own the information?
- How can you motivate them to listen to you?
- How to Maintain Orthogonality
- Design independent, well-defined components.
- Keep your code decoupled.
- Avoid global data.
- Refactor similar functions.
- Things to prototype
- Architecture
- New functionality in an existing system
- Structure or contents of external data
- Third-party tools or components
- Performance issues
- User interface design
- Architectural Questions
- Are responsibilities well defined?
- Are the collaborations well defined?
- Is coupling minimized?
- Can you identify potential duplication?
- Are interface definitions and constraints acceptable?
- Can modules access needed data—when needed?
- Debugging Checklist
- Is the problem being reported a direct result of the underlying bug, or merely a symptom?
- Is the bug really in the compiler? Is it in the OS? Or is it in your code?
- If you explained this problem in detail to a coworker, what would you say?
- If the suspect code passes its unit tests, are the tests complete enough? What happens if you run the unit test with this data?
- Do the conditions that caused this bug exist anywhere else in the system?
- Law of Demeter for Functions
- An object’s method should call only methods belonging to:
- Itself
- Any parameters passed in
- Objects it creates
- Component objects
- How to Program Deliberately
- Stay aware of what you’re doing.
- Don’t code blindfolded.
- Proceed from a plan.
- Rely only on reliable things.
- Document your assumptions.
- Test assumptions as well as code.
- Prioritize your effort.
- Don’t be a slave to history.
- When to Refactor
- You discover a violation of the DRY principle.
- You find things that could be more orthogonal.
- Your knowledge improves.
- The requirements evolve.
- You need to improve performance.
- Cutting the Gordian Knot
- When solving impossible problems, ask yourself:
- Is there an easier way?
- Am I solving the right problem?
- Why is this a problem?
- What makes it hard?
- Do I have to do it this way?
- Does it have to be done at all?
- Aspects of Testing
- Unit testing
- Integration testing
- Validation and verification
- Resource exhaustion, errors, and recovery
- Performance testing
- Usability testing
- Testing the tests themselves