Tuesday, March 29, 2011

The Importance of (Variable) Names

Having clear, meaningful variable names is an important factor in writing understandable and maintainable code.


By the time Princess Ann had reached the northernmost outpost within the kingdom, she was losing hope. Her father, King Fredrick, had sent her on a quest to save the kingdom from impending darkness almost a month ago. So far, Ann had found nothing. Meanwhile reports of roaming dragons and hordes of goblins increased throughout the kingdom. Ann felt completely demoralized.


The outpost of Garroow had been hit particularly hard by the recent chaos. The goblin attacks had been increasing in recent weeks. The commander, Sir Aat, had sent word to Ann's father that the outpost was in desperate need of reinforcements. At a loss for better stops on her quest, Princess Ann headed north to Garroow.


The situation in Garroow was worse than she had expected. During her first night at the outpost, a small goblin attack almost overwhelmed it. The fifty person garrison barely held off just three, relatively lethargic, goblins. She heard the captain shouting orders at his solders: “Ut, guard the South wall. No, I meant Ot. Ut, stay where you are.” “Drex, swap places with Plex, we need an archer on the wall not a blacksmith.” “Et, secure that door.”


Eventually, the soldiers repelled the attack and extinguished the fires. However, the lingering feeling of chaos and confusion continued to bother Ann. It worried her that the garrison's response had been so disorganized. It was like watching a turtle try to chase its own tail. The problem was not the number of soldiers in Garroow, but rather how they were being commanded.


Ann resolved to fix the situation before leaving the garrison. She spent the entire night pondering the different algorithmic strategies, certain that one of them would help the garrison run more efficiently. As she had been taught from an early age: almost every problem has an algorithmic solution. She debated the pros and cons of using dynamic programming to organize communication lines, using a min-max search to optimize strategy, and using randomization to avoid local minima. But none of these approaches seemed to address the core problem. Ultimately, the true issue dawned on her at 3am, and she fell asleep confident that she knew how to fix the situation.


“Sir Aat,” she addressed the commander at breakfast the next morning. “We need to discuss the attack last night.”


“Yes.” agreed the commander. “Now you see why we need the reinforcements.”


“No. I do not.” responded Ann.


The commander looked shocked. The rest of the dining hall fell silent. Everyone waited to see what Ann said next.


“What you need are better names.” Ann continued.


The commander laughed deeply. “You don't understand. We have already improved our names. When a soldier joins the outpost, they are assigned a new name. Every name is short, so that commanders can call out orders quickly in battle.”


“No. It is not.” disagreed Ann. “It is inefficient.”


“No offense Princess Ann, but what do you know about commanding in battle?” he asked.


“Only what I observed last night. But from that limited introduction, I can assure you that the names are hurting your efforts.”


“I think you are mistaken.” declared the commander. “They allow us to issue commands at incredible speeds.”


“Yes they do.” agreed Ann. “But they are prone to mistakes. Last night, you corrected yourself 89 different times. The names are too similar and thus too easy to confuse. Plex and Drex. Ut, Ot, Et, and Aat. The short names do not help!”


“Ha! What would you suggest?” scoffed the commander.


“Use descriptive names. For example, Plex should be called 'South Tower Archer' or at least 'Archer 1'. That more accurately reflects his role.”


“That is crazy!” bellowed the commander as he slammed his mug of coffee on the table. “Do you know how long it takes to say 'South Tower Archer' in the heat of battle? We would waste valuable time.”


“Do you know how long it takes to say 'Drex, swap places with Plex, we need a archer on the wall not a blacksmith.'? Any measure of efficiency needs to take into account the time spent on corrections.” countered Ann.


The commander had no response for that.


“And what about you?” Ann continued. “Why not have them call you Commander or Captain?”


“Our names already reflect rank.” replied the commander. “The names proceed down the ranks in alphabetical order. It allows any solder to instantly know who outranks them! It makes life simple!”


“No. It does not.” corrected Ann again. “In order for the solders to even refer to each other, they have to learn new made-up names. Why not have them learn the ranks instead? Either way they have to learn something new. Only, in this case, the ranks mean something.”


“But we have a good system!” argued the commander.


Ann sighed. “It is like programming a complex algorithm.” she explained. “Using very short variable names can make it feel more efficient to program, because you can type out the code faster. But, in the long run, it can do more harm than good. It becomes easy to make mistakes and difficult to sort out what is happening. Often times, slightly longer names can make a significant difference.”


The commander opened his mouth to argue, but was unable to think of a rebuttal. Instead, he sat at his table, mouth open, with a confused look on his face. After a while he spoke.


“I think you might have a point.” Secretly, the commander also felt a small pang of relief. He had never been fond of his own assigned name. He often found himself day dreaming of his solders snapping a salute and shouting “Yes Commander!” in unison. Maybe this change would not be so bad after all.


That afternoon, the commander changed every soldier's name to be longer, but more meaningful. Over the next few days, the troops stumbled through drills, getting used to their longer names. But soon, Ann began to see efficiency improve.


A week later, on Ann's final night in Garroow, there was another goblin attack. This time the invading force consisted of 10 highly trained goblin special forces troops. The Garroow soldiers turned away the attack with ease.


As Ann left the garrison, she took a small bit of pride in the dramatic improvements in the forces there. After indulging in the brief moment of happiness, she turned her horse East and continued on her quest to save the kingdom.


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If you are interested in learning more about writing good code, check out: The Importance of Comments: A Tale of The Baker's Apprentice, The Curse of Excessive Commenting, or The Importance of Unit Testing Magic Spells.

2 comments:

  1. Small mistake: “The Garroow soldiers turned away the attack with easy.” Should be “[…] with ease.”

    ReplyDelete
  2. couldn't agree more than this. variable name is first step in making code standard and helps a lot while reading code and debugging code.

    Javin
    What is abstraction in Java

    ReplyDelete

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