Basics in

About Basics

• Elixir is dynamically-typed.
  • The type of a variable is only checked at run-time.
• Using the match = operator, we can bind a value of any type to a variable name:
  • It is possible to re-bind variables.
  • A variable may have any type of value bound to it.

Modules

• Modules are the basis of code organization in Elixir.
  • A module is visible to all other modules.
  • A module is defined with defmodule.

Named Functions

• All named functions must be defined in a module.

  • Named functions are defined with def.
  • A named function may be made private by using defp instead.
  • The value of the last expression in a function is implicitly returned.
  • Short functions may also be written using a one-line syntax.

  def increment(n) do
    n + 1
  end
  
  defp private_increment(n) do
    n + 1
  end
  
  def short_increment(n), do: n + 1
  

• Functions are invoked using the full name of the function with the module name.

  • If invoked from within its own module, the module name may be omitted.

• The arity of a function is often used when referring to a named function.

  • The arity refers to the number of arguments it accepts.

  # add/3, because the arity is 3
  def add(x, y, z), do: x + y + z
  

Naming conventions

Module names should use PascalCase. A module name must start with an uppercase letter A-Z and can contain letters a-zA-Z, numbers 0-9, and underscores _.

Variable and function names should use snake_case. A variable or function name must start with a lowercase letter a-z or an underscore _, can contain letters a-zA-Z, numbers 0-9, and underscores _, and might end with a question mark ? or an exclamation mark !.

Integers

Integer values are whole numbers written with one or more digits. You can perform basic mathematical operations on them.

Strings

String literals are sequences of characters surrounded by double quotes.

string = "this is a string! 1, 2, 3!"

Standard library

• The documentation is available online at hexdocs.pm/elixir.
• Most built-in data types have a corresponding module, e.g. Integer, Float, String, Tuple, List.
• The Kernel module is a special module.
  • Provides the basic capabilities on top of which the rest of the standard library is built.
  • Automatically imported.
  • Its functions can be used without the Kernel. prefix.

Code comments

Comments can be used to leave notes for other developers reading the source code. Single line comments in Elixir are preceded by #.