Variable does not exist compilation error while accessing a function in a module in elixir

Question

I am new to Elixir. I am trying to run a function inside a module. My code in the file is as follows:

defmodule greeter do

  def print() do
    IO.puts "Hello workd" 
  end

  def print(name) do
    IO.puts "Hello " <> name 
  end

  defp print(name,age) do
    IO.puts "Hello " <>name<>" My age is "<> age 
  end

end

greeter.print()
greeter.print("Xyxss")

When I run elixirc filename.ex on my command line I get the following error:

warning: variable "greeter" does not exist and is being expanded to "greeter()", please use parentheses to remove the ambiguity or change the variable name
functions.ex:1
== Compilation error in file functions.ex ==
** (CompileError) functions.ex:1: undefined function greeter/0
   (stdlib) lists.erl:1354: :lists.mapfoldl/3
   (elixir) expanding macro: Kernel.defmodule/2
   functions.ex:1: (file)

I am unable to solve the given error. Can somebody help me with this?

Answer 1

I would put a correct answer here, since the answer provided by @J.Sebio is plain wrong.

The module name in Elixir must be an atom. Both examples below work perfectly:

iex(1)> defmodule :foo, do: def yo, do: IO.puts "YO"
iex(2)> :foo.yo
YO

iex(3)> defmodule :"42", do: def yo, do: IO.puts "YO"  
iex(4)> :"42".yo                                     
YO

The thing is: in Elixir, capitalized term is an atom:

iex(5)> is_atom(Greeting)
true

That is why capitalizing the name of the module worked. Also, greeting is a plain variable, that is why the compiler tries to resolve it inplace and throws an error.

Answer 2

In elixir the modules are written capitalized, and normally written CamelCase, so, in your case you have to rewrite your code to:

defmodule Greeter do

    def print() do
        IO.puts "Hello workd"
    end

    def print(name) do
        IO.puts "Hello " <> name
    end

    defp print(name,age) do
        IO.puts "Hello " <>name<>" My age is "<> age
    end

end

Greeter.print()
Greeter.print("Xyxss")