Elixir Functions Error Fix

The Hook

You will learn how to fix common functions errors. This matters because understanding this concept is essential for productive development. Built by the developers of Doda Browser, DodaZIP, and Durga Antivirus Pro.

Quick Fix

Functions

The wrong approach and the correct fix are shown below:

Wrong:

def greet(name), do: "Hello #{name}"

Output:

Right:

def greet(name), do: "Hello #{name}"
def greet(name, greeting \\ "Hello"), do: "#{greeting} #{name}"
def greet("admin"), do: "Welcome admin"
def greet(name), do: "Hello #{name}"

Output:

Prevention

Multiple clauses pattern match args. Defualt params with \. Guard clauses with when.

Common Mistakes with functions

1. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
2. Non-exhaustive pattern matches that compile with warnings then crash at runtime
3. Misunderstanding that String is [Char] with poor performance for large text operations

These mistakes appear frequently in real-world ELIXIR code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ