Function signature should be error prune

TL;DR: Don't use Optional Arguments before mandatory ones. In fact: Don't use Optional Arguments at all

Problems

• Fail Fast principle violation

• Readability

Solutions

1. Move your optional arguments last.

2. Avoid Optional Arguments.

Context

Optional Arguments are a code smell.

Defining optional arguments before mandatory ones is an error.

Sample Code

Wrong

<?

function buildCar($color = "red", $model){...}  
// First argument with optional argument

buildCar("Volvo")}}  
// Runtime error: Missing argument 2 in call to buildCar()

Right

<?

function buildCar($model, $color = "Red", ){...}

buildCar("Volvo")}} 
// Works as expected

def functionWithLastOptional(a, b, c='foo'):
    print(a)
    print(b)
    print(c)
functionWithLastOptional(1, 2)

def functionWithMiddleOptional(a, b='foo', c):
    print(a)
    print(b)
    print(c)
functionWithMiddleOptional(1, 2)

# SyntaxError: non-default argument follows default argument

Detection

[X] Automatic

Many Linters can enforce this rule since we can derive it from function signature.

Also, many compilers directly forbid it.

Tags

• Readability

Conclusion

Try to be strict when defining functions to avoid coupling.

Relations

Code Smell 19 — Optional Arguments

Maxi Contieri ・ Nov 7 '20

#codenewbie #oop #tutorial

More Info

Fail Fast

Maxi Contieri ・ Dec 6 '20

#codenewbie #programming #webdev #oop

Rule on Sonar Source

Disclaimer

Code Smells are just my opinion.

Credits

Photo by Manuel Torres Garcia on Unsplash

Programs are meant to be read by humans and only incidentally for computers to execute.

Donald Knuth

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

#codenewbie #tutorial #codequality #beginners