44 lines
1.2 KiB
Elixir
44 lines
1.2 KiB
Elixir
defmodule Agents do
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use Koans
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@intro "Agents"
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koan "Agents maintain state, so you can ask them about it" do
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{:ok, pid} = Agent.start_link(fn -> "Hi there" end)
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assert Agent.get(pid, &(&1)) == ___
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end
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koan "Agents may also be named so that you don't have to keep the pid around" do
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Agent.start_link(fn -> "Why hello" end, name: AgentSmith)
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assert Agent.get(AgentSmith, &(&1)) == ___
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end
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koan "Update to update the state" do
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Agent.start_link(fn() -> "Hi there" end, name: __MODULE__)
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Agent.update(__MODULE__, fn(old) ->
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String.upcase(old)
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end)
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assert Agent.get(__MODULE__, &(&1)) == ___
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end
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koan "Use get_and_update when you need to read and change a value in one go" do
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Agent.start_link(fn() -> ["Milk"] end, name: __MODULE__)
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old_list = Agent.get_and_update(__MODULE__, fn(old) ->
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{old, ["Bread" | old]}
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end)
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assert old_list == ___
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assert Agent.get(__MODULE__, &(&1)) == ___
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end
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koan "Somebody has to switch off the light at the end of the day" do
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{:ok, pid} = Agent.start_link(fn() -> ["Milk"] end, name: __MODULE__)
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Agent.stop(__MODULE__)
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assert Process.alive?(pid) == ___
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end
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end
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