Clean Code: Motivations, Challenges, and a Book Review

Yet attentiveness toeven more critical

professionalism than vision

detail is an foundation of is any grand

Clean Code:A Quick Review

linkedin.com/in/elgeish




Things Covered Here

1 About the Book

2 Why Clean Code?

3 Things We Liked

4 Things We Disliked

2




Coding for Machines

Quick Reminder

IN AX, DX

MOV [ES:DI], AX

INT 3

MOV AX, [DS:SI]

OUT DX, AX

3




About the Book




It’s all about craftsmanshipA Handbook of Agile Software Craftsmanship

5

• Amazon best seller in software testing

• Uncle Bob is also known for SOLID

• He also wrote The Clean Coder (2011)

https://www.amazon.com/Clean-Code-Handbook-Software-Craftsmanship/dp/0132350882/

https://www.amazon.com/Clean-Code-Handbook-Software-Craftsmanship/dp/0132350882/




Why Clean Code?




Because we write code for humans, and not just machinesCode Is Speech:

7Source: xkcd.com/1421




“We are honest about the state of our code because code is never perfect”, and that’s – actually – desirable!

Code Is Never Perfect:

8Source: xkcd.com/844




“[Coding] stops as soon as minimally-accepted results are found” - Guillaume Ferrero (1894)

Principle of Least Effort:

9

Source: xkcd.com/221




Seeking delayed gratification (clean code) => a more successful lifeThe Stanford Marshmallow Experiment:

10

Acceptable result?

Demand excellence

Have a cookie!

No

Yes

Have two cookies!




The secret is dopamineA Neuroscientific Look at Meh Code

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• Coding is iterative• A failure causes low dopamine levels• Task completion => a spike in dopamine levels• Moving on to a new task => dopamine levels rise

“[Yet] newness is no virtue and oldness is no vice. Truth and beauty and goodness are not determined by when they exist.”

- Pastor John Piper




Things We Liked




Can save your lifeCoding Standards

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• Consistent indentation style => fewer bugs • Reduce attention deficit (Thinking, Fast and Slow)• Pick them, stick to them, and automate if possible

“Code formatting is about communication,and communication is the professional

developer's first order of business.”

https://www.amazon.com/Thinking-Fast-Slow-Daniel-Kahneman/dp/0374533555




As if you’re naming a first-born childMeaningful Names

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• We spend disproportionately more time reading coding (than writing it)

• Use the shortest most expressive name that you can find easily

“[An entity's name] should tell you why it exists, what it does, and how it is used.”




Keep everything smallMinimalism

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• Files, classes, functions, etc. should be small• SRP: Do one thing; do it well; and do it only!




// Do you really need this comment?Comments

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• When Bugs Become Features: Norman Doors• Can’t test a comment (TODO vs. @Expiration)• Comments are spells of magic; they charm the

reader into thinking they must be truer than code

“The proper use of comments is to compensate for our failure to express

[ourselves] in code.”

http://www.jnd.org/dn.mss/when_bugs_become_fea.html

https://github.com/elgeish/ExpAnn




Things We Disliked




Sometimes renaming might introduce bugsMeaningful Names

18

• Tangled code reviews might hide an issue• Binary serialization might use private field names;

renaming them may cause compatibility issues!




Not the cleanest code

Uncle Bob showed the use of comments to explain intent in this example:

public int compareTo(Object o) { if (o instanceof WikiPagePath) { WikiPagePath p = (WikiPagePath) o; String compressedName = StringUtil.join(names, “”); String compressedArgumentName = StringUtil.join(p.names, “”); return compressedName.compareTo(compressedArgumentName); } return 1; // we are greater because we are the right type. }

Comments

19




How would you review his code?

Unnecessary Objects: There are better ways to compare iterables without creating throwaway objects (and especially not strings that are expensive to create – see Item 5 in Effective Java).

Variable Names: they’re not meaningful.

Choice of Words: "we" is not a known reference in programming; "this" is though, and it would have been more apt here.

Eliminate the Comment Altogether: Implement Comparable{T} instead, or skip the type check; compareTo should throw ClassCastException if the types are different. Comparing two objects of different types violates many contracts.

Comments

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https://www.amazon.com/Effective-Java-2nd-Joshua-Bloch/dp/0321356683




SRPFunctions

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• “Functions should either do something or answer something, but not both”

• Yet, the Command-Query pattern is sometimes pragmatic in concurrent programming:• test-and-set: writes to a memory location, and

returns the old value• compare-and-swap: compares the value x at a

given memory location to a given value y, and sets the former to a given new value z only if x is equal to y; the return value indicates whether or not the swap occurred




Missing sectionsFunctions

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• Generics• Overloading• Default Parameters• Scope (visibility)• Testability




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Clean Code: Motivations, Challenges, and a Book Review

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Transcript of Clean Code: Motivations, Challenges, and a Book Review