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@jwhiteman jwhiteman/example.ex
Last active Dec 11, 2015

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Elixir vs Ruby (pattern matching vs conditional logic)
# elixir
defmodule Example do
def work(_msg) do
IO.puts "called 1st function"
end
def work(_msg, data=[_a, _b, _c]) do
IO.puts "called 2nd function #{inspect data}"
end
def work(_msg, data=[a, b, _c, _d]) when is_integer(a) and is_list(b) and a > 5 do
IO.puts "called 3rd function #{inspect data}"
end
def work(_msg, data=[_a, _b, _c, _d]) do
IO.puts "called 4th function #{inspect data}"
end
end
Example.work("ok") # calls first function
Example.work("ok", [:a, :b, :c]) # calls second function
Example.work("ok", [6, [:i_am_a_list], 11, 12]) # calls third function. 'a' is an integer greater than six, 'b' is a list.
Example.work("ok", [:a, 42, 99, "hello, world"]) # calls fourth function.
# to get the same output from the same data in Ruby
class Example
attr_reader :msg, :data
def initialize(msg, data = nil)
@msg = msg
@data = data
end
def work
if data
if data.length == 3
puts "called 2nd function #{data}"
elsif data[0].kind_of?(Integer) && data[0] > 5 && data[1].kind_of?(Array)
puts "called 3rd function #{data}"
else
puts "called 4th function #{data}"
end
else
puts "called first function"
end
end
end
Example.new("ok").work
Example.new("ok", [:a, :b, :c]).work
Example.new("ok", [6, [:i_am_a_list], 11, 12]).work
Example.new("ok", [:a, 42, 99, "hello, world"]).work
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