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Jorge Tovar
Jorge Tovar

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Pragmatic Programmer - Book Notes

Pragmatic Programmer

Pragmatic Programmer Book

Pragmatic philosophy

  • Your life it's your life
    • Craftsmanship
    • Early adopter
  • Responsibility
    • Offer options
  • Software Entropy
    • Simplicity
    • Maintenance
  • Good enough software
    • Quality is a requirement
  • Your knowledge portfolio:
    • Investment in knowledge always pays the best interest
    • Read nontechnical books
    • Read conceptual books
    • Learn one new language every year
  • Communicate
  • Testability is key

Pragmatic approach

  • The essence of good design: ETC
  • DRY: Code, Data, Documentation (Knowledge)
    • Don't abstract too early, wait until you have copied and pasted a couple of times, examples are needed to create good abstractions
  • Orthogonality:
    • Eliminate effects between unrelated things
    • Understandable, and easier to debug, test and maintain
    • Design patterns
    • SOLID
    • Prefer composition and FP languages
  • Reversibility:
    • Flexible architecture
    • Have options
  • Tracer bullets:
    • Code lean and complete
    • Find the target
  • Prototypes and post-it notes:

    • Information gathering
    • Is coupling minimized
    • Collaborations between components well-defined
    • Responsibilities
    • Interfaces and data clear and available
  • Domain languages:

    • Program close to the problem domain
  • Estimation:

    • I'll back to you
    • optimistic, most likely, and pessimistic
    • model building: someone that already did it

Basic Tools

Be more productive with your tools

  • The power of plain text:
    • Self-describing data
  • Shell games
  • Power Editing
  • Debugging skills
    • localhost test
    • Explain to someone else
  • Text manipulation
    • Unix: sed, awk
    • Scripting languages: Python
  • Engineering daybooks

Pragmatic Paranoia

Validate all the information we're given, assertions of bad data, and distrust data from potential attackers

  • Design by contract
    • Preconditions, postconditions: Clojure Specs
  • Dead programs tell no lies
    • Crash early
    • Defensive programming is a waste of time let it crash! (Supervisor)
  • Assertive programming
    • Use assertions to prevent the impossible
  • How to balance resources
    • Release free resources
  • Don't outrun your headlights
    • take small steps always

Bend or break

Make our code as flexible as possible, a good way to stay flexible it's to write less code

  • Decoupling
    • Allow flexibility
    • Shy code that promotes cohesion
    • Law of Demeter: Depend on abstractions
    • Avoid global data
    • Avoid inheritance
  • Juggling the real world
    • Events
    • Finite state machine
    • Observer
    • Publish/Subscribe (Channels)
    • Reactive Streams
  • Transforming programming
    • Think in programs like Input Output and transformation of data
    • Process of data
    • find . -name '*.java' | xargs wc -l | sort -n | tail -11 | head -10
    • Programming is about code but programs are about data
  • Inheritance tax
    • Coupling
    • Interfaces to express polymorphism
  • Configuration
    • Parameterize your app using external configuration


  • Concurrency: Two pieces of code run at the same time using Fibers, Threads, and process
  • Parallelism: Hardware that can do two things at once
  • Breaking temporal coupling
  • Avoid shared state
  • Actor and process
  • Blackboards
    • Communication using Kafka or other streaming services

While you are coding

  • Listen to your lizard brain
    • Give time and space to your brains to organize your ideas
  • Algorithm speed
  • Refactoring
    • Rethink
    • Gardening
    • Unit test
    • (Duplication, Not DRY, Bad performance, Outdated knowledge, Test passing. Nonorthogonal)
    • Redesign
    • Refactor early and often is like a surgery
  • Test the code
    • Feedback
    • Improve design
    • Embrace TDD
  • Property-based testing
  • Security
    • Authentication
    • I/O data
    • Principle of least privilege
    • Up to date
    • Encrypt sensitive information
  • Naming
    • In programming all the things have names and reveal the intent and belief of the system
    • Communication

 Before the project

  • Requirements Pit
    • User doesn't know what he wants
    • Our job is to help businesses to understand what they want
    • Improve the feedback loop
    • BDUF is not a good thing
    • Work with the user to think like one
  • Solving de puzzle
    • Think out of the box
    • Make time to think in the unfocused mode
  • Working together
    • Pair programming
    • Mob programming
  • Agile
    • It's about values, context, and feedback loop

Pragmatic Teams

  • Pragmatic Teams
    • No broken windows
    • Be aware of the environment and health of the project
    • DRY
    • Small teams
    • Cross-functional teams Tracer bullets
    • Automation
    • Create and identity (Team name)
    • Schedule time to improve knowledge portfolio
  • Context
    • Use the right tools and practices
    • Software delivery (When release flow is slow status meetings are high)
    • Kanban
  • The programmer starter kit
    • Version control
    • Ruthless testing
      • Unit, Integration, Component, Performance
      • If modules don't work well as a unit, they won't work well as a system
      • Saboteurs: Chaos engineering
  • Automate everything
    • Software delivery es fully automated
  • Delight your users
    • What are your expectations
    • Deliver quality not code
  • Pride and prejudice
    • Code that you feel proud
    • Collective ownership

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