ErrorHandling.exs

defmodule MyModule do
  def doSomething(num) do
    if num != 1 do
      {:ok, num + 1}
    else
      {:error, "some reason"}
    end
  end
end

Try-catch style

try do
  {:ok, res1} = MyModule.doSomething(0)
  {:ok, res2} = MyModule.doSomething(res1) # error raised here, as pattern mismatching
  {:ok, res3} = MyModule.doSomething(res2)
  IO.puts res3
rescue 
  MatchError -> IO.puts "something wrong"
end

Go/C style

res1 = 
  case MyModule.doSomething(0) do
    {:ok, data} -> data
    {:error, reason} -> raise "something wrong in step 1"
  end
  
res2 = 
  case MyModule.doSomething(res1) do
    {:ok, data} -> data
    {:error, reason} -> raise "something wrong in step 2"
  end

res3 = 
  case MyModule.doSomething(res2) do
    {:ok, data} -> data
    {:error, reason} -> raise "something wrong in step 3"
  end

is it Either String Int in Haskell ? reference

Damn it, why the other part of comment was removed....