README.md

Software Engineering

Qualities of good code - OOP edition

what is software engineering?

ok, so what is ~~~software~~~ engineering?

engineering is the application of scientific, economic, social, and practical knowledge in order to invent, design, build, maintain, and improve structures, machines, devices, systems, materials and processes

software engineering is the study and application of engineering to the design, development, and maintenance of software

code = API

Even private code has an API

why

• 75% reading (understanding code) https://blog.codinghorror.com/when-understanding-means-rewriting/
• easier maintenance
• it's cool

consistency

• naming
  • increase/decrease
  • add/delete
  • insert/remove
  • prev vs previous
• in names, parameters etc.
• use of standard patterns
• error handling e.g. throw Error vs console.error()
• ... consistent code style in general

Examples

• git
  • git fetch + git merge = git pull vs git checkout + git branch = git checkout -b
  • git commit ignores local, unstaged changes in foo.txt; git commit foo.txt doesn’t
  • array_key_exists('b', $b) vs property_exists($c, 'd')

orthogonality

• functions have no side effects

Examples

• sides of rectangle vs square

discoverability

• it should be easy to understand code by exploring it

adaptation

information hiding

• encapsulation - logical hinding

loose coupling

• inheritance couples code more than composition
• favor object composition over class inheritance

model the problem domain

be minimally complete

• make you code do all that is needed, but nothing more

beware of extra generality

• you may never need extra generality
• when it comes you may have more knowledge how about the use of your code
• it's easier to add code to simple API vs complex one

Demeter Law

Heisenbugs

• state bugs

design patterns

• GoF
• why design patterns?

SOLID

• of course :-D

class should define what to do not how its done

prefer composition over inheritance

• yup!

Command Query Separation

• https://en.wikipedia.org/wiki/Command–query_separation

Books

• https://en.wikipedia.org/wiki/Object-Oriented_Software_Construction
• https://smile.amazon.com/Enterprise-Integration-Patterns-Designing-Deploying/dp/0321200683