模块定义 defmodule
函数定义 def
私有函数 defp --相当于其他语言 private
iex(29)> defmodule Math do
...(29)> def sum(a, b) do
...(29)> a + b
...(29)> end
...(29)> end
iex(30)> Math.sum(1, 2)
3
捕捉语法 定义函数的快捷方式
iex(31)> fun = &(&1+1)
#Function<6.90072148/1 in :erl_eval.expr/5>
iex(32)> fun.(2)
3
等价于
iex(33)> a = fn x -> x + 1 end
#Function<6.90072148/1 in :erl_eval.expr/5>
iex(34)> a.(2)
3
默认参数
iex(38)> defmodule Concat do
...(38)> def join(a, b, sep \\ " ") do
...(38)> a <> sep <> b
...(38)> end
...(38)> end
iex(39)> IO.puts Concat.join("hello", "word")
hello word
:ok
iex(40)> IO.puts Concat.join("hello", "word", " ")
hello word
:ok