1 S.O.L.I.D

During the first week of class under The Beginning in the orientation module we briefly discussed S.O.L.I.D.

My colleagues and I disagree on when this should be introduced. I believe S.O.L.I.D should be discussed now… at the very beginning of the semester. To do so, we will have to split the word:

S.O.L.I.D = (S.O.) + (L.I.D.)

I will forgo my hilarious wordplay.. this time.

Example 1: The Beginning... S.O.

Why are we starting with S.O.? First… we have all the tools we need to understand it:

• S - Single Responsibility Principle
• O - Open/Closed Principle

Second… these emerge naturally out of how we write code. We want to write reusable functions and classes. We want to be able to extend those classes without modifying the underlying code. Think about:

• std::vector
• std::list
• std::unordered_map
• std::iterator

That leaves three (3) letters for us to discuss:

• L - Liskov Substitution
• I - Interface Segregation
• D - Dependency Inversion

Combining everything, we are left with

• S - Single Responsibility Principle

  Every class, module, or interface has one responsibility (i.e., purpose).

• O - Open/Closed Principle

  It should be possible to extend a class, module, or function without modifying the original code.

• L - Liskov Substitution

• I - Interface Segregation

  Fight the urge to throw in the kitchen sink. Focus on creating problem specific interfaces, not monolithic kitchen-sink-interfaces. This requires us to codify how to decompose a large problem (high-level design).

• D - Dependency Inversion

  Modules should not directly handle low-level calls and operations. Consider the C FILE* vs the C++ ofstream and ifstream.

Think back to Review 03 Examples 6 through 9…

2 Tools of the Trade

At the start of the semester… I introduced the names of various tools. In my examples (Reviews 01 to 03) I demonstrated a few of these tools. You were required (and in some cases all-but-required) to use a few of these tools on your own.

Let us take stock of our discussions and exercises thus far.

Category	Tool	Assignments	Lecture / Recordings
General	Linux	✔	✔
General	SSH	✔	✔
Build System	Makefiles	✔	✔
Compilation	g++	✔	✔
Methodology	Unit Testing / TDD	✔	✔
Editor	Vim	Hopefully	✔
Version Control	Git	Hopefully	✔
Documentation	Doxygen	Read Only	✔
Documentation	Rustdoc	Not Yet	✔ (Review 03)
Documentation	Pydoc	Not Yet	Not Yet
Configuration & Testing	Tox	Not Yet	✔ (Review 03)
Build & Configuration	Gradle	Not Yet	Not Yet
Code Style Analysis	CPPLint	Not Yet	✔
Code Style Analysis	Checkstyle	Not Yet	Not Yet
Code Style Analysis	Pycodestyle / Pylint	Not Yet	Not Yet
Design (UML Class Diagrams)	PlantUML	Maybe	✔
Design (UML Sequence Diagrams)	SDEdit	Not Yet	Not Yet