概要

paiza.ioでelixirやってみた。
型が分からないので、調べてみた。

サンプルコード

defmodule TypeBy do
  @spec get(any) :: String.t()
  def get(x) do
    dict = %{
      &is_atom/1      => "Atom",
      &is_binary/1    => "Binary",
      &is_bitstring/1 => "BitString",
      &is_boolean/1   => "Boolean",
      &is_float/1     => "Float",
      &is_function/1  => "Function",
      &is_integer/1   => "Integer",
      &is_list/1      => "List",
      &is_map/1       => "Map",
      &is_number/1    => "Number",
      &is_pid/1       => "Pid",
      &is_reference/1 => "Reference",
      &is_tuple/1     => "Tuple",
    }
    typename_list = Enum.filter_map(dict, fn {pred, _} -> 
        pred.(x) 
    end, fn {_, name} -> 
        name 
    end)
    if Enum.empty?(typename_list) do
      "unknown type"
    else
      Enum.join(typename_list, " & ")
    end
  end
end

x = "hello"
IO.puts "type: #{TypeBy.get(x)}"
x = 13
IO.puts "type: #{TypeBy.get(x)}"
x = 'hello'
IO.puts "type: #{TypeBy.get(x)}"
x = 3.14
IO.puts "type: #{TypeBy.get(x)}"
x = true
IO.puts "type: #{TypeBy.get(x)}"
x = :hoge
IO.puts "type: #{TypeBy.get(x)}"
x = {6}
IO.puts "type: #{TypeBy.get(x)}"
x = [7]
IO.puts "type: #{TypeBy.get(x)}"

実行結果

type: Binary & BitString
type: Integer & Number
type: List
type: Float & Number
type: Atom & Boolean
type: Atom
type: Tuple
type: List

成果物

以上。