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The Pragmatic Programmer

The tried-and-true, evergreen guide for being a programmer


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.

Don’t Live with Broken Windows

Fix bad designs, wrong decisions, and poor code when you see them. Invest Regularly in Your Knowledge Portfolio Make learning a habit.

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.

Prototype to Learn

Prototyping is a learning experience. Its value lies not in the code you produce, but in the lessons you learn.

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.

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.

Minimize Coupling Between Modules

Avoid coupling by writing “shy” code and applying the Law of Demeter.

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.

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.

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.

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

‘Nuff said.

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.