finder.exs

finder.exs

defmodule Finder do
  @doc """
  `run` takes a word or phrase via the `search_term` argument and passes it to `find'. But primarily `run` returns a list of files from a specified directory and passes it to the `find` function.
  """

  def run(directory_path, search_term) do
    [head|tail] = File.ls!(directory_path)
    find([head|tail], 0, directory_path, search_term)
  end

  @doc """
  `find` returns to the command line how many times and in which files the `search_term` occurs. It takes 4 arguments. The first is a list, the list of files to search through which is passed in by run. The second is an accumulator that keeps track of how many files have been searched. The third is the search term initially passed into `run`.
  """

  def find([head|tail], files_searched, directory_path, search_term) do
    if tail == [] do
      IO.puts "Complete! Searched #{files_searched} files in total."
    else
      file = File.read!(directory_path <> "/" <> head)
      outcome = String.contains?(file, search_term)
      case outcome do
        true ->
          IO.puts "Found term in: #{head}."
          # Splits on the search term and tests the length of the array - 1 because the number of terms is always going to be one less than the length of the array.
          occurences = length(String.split(file, search_term)) - 1
          IO.puts "Term occured #{occurences} time/s." # Did it this way because I thought it was more readable.
          find(tail, files_searched + 1, directory_path, search_term)
        false ->
          find(tail, files_searched + 1, directory_path, search_term)
      end
    end
  end
end

The idea here is to search a directory of text files for the search term provided.

Example: Finder.run("100-txt-files", "cat")

The first thing that I would do is split out the if tail == [] into its own def find clause and just match it explicitly. In general you really want each function to just do 1 small thing.

Prefer string interpolation over concatenation: "#{directory_path}/#{head}" vs. directory_path <> "/" <> head.

Since you're going to call find at the end of your function anyway I would tend to use if String.contains?(file, search_term) here instead of the case. Its only going to return a boolean value and you don't need to worry about the false case.