Kotlin Code Smell 29 - Regular Expression Abusers
From Spaghetti Code to Readable Magic
I've started to work as a software engineer at 2014, however, I started to write code at high-school.
My first language was Assembly, but still, I fall in love with the possibilities to make the computer to do as you wish, shortly after that I started to write in C.
Later on I studied a practical engineering in electricity, and during this time discovered that I preferred much more writing code than design electrical components.
As a result of this understanding I decided to switch and study bachelor degree in computer science in Reichman university, where the focus was of the Java language.
Today I'm working at SumUp using Kotlin, SpringBoot & Micronaut, Cassandra and Kafka
RegEx is a wonderful tool, we should use them carefully and not look smart.
Problem
Readability
Maintainability
Testability
Intention Revealing
Solution
Use regular expressions just for string validation.
If you need to manipulate objects, don't make them strings.
Sample Code
Wrong
val regex = "^\\+(?:[0-9a-zA-Z][– -]?){6,14}[0-9a-zA-Z]$".toRegex()
Right
val prefix = """\+"""
val digit = "[0-9a-zA-Z]"
val space = "[– -]"
val phoneRegex = "^$prefix(?:$digit$space?){6,14}$digit$".toRegex()
Conclusion
Regular expressions are a great tool for string validation. We must use them in a declarative way and just for strings.
Names are very important to understand pattern meanings.
If we need to manipulate objects or hierarchies, we should do it in an object way.
Unless we have a conclusive benchmark of impressive performance improvement.
