搞一个例子，而没有实际的目标，做起来真是烦人。几次三番都想放弃。
后来想想，即使最后完成不了完整的服务器，把需要的知识点搞搞，摸熟悉也是好的。
这里没有完整的项目目录，主要是对需要的指点进行整理。要完整写个教材的话，话费我太多时间，恐怕我继续不下去。
先搞个建模吧。玩家数据目前如下
defmodule Player do
@behavior Access
defdelegate [fetch(t, key), get_and_update(t, key, list)], to: Map
defstruct [:base_info]
def new(id) do
%Player{
base_info: BaseInfo.new(id)
}
end
end
defmodule BaseInfo do
@behavior Access
defdelegate [fetch(t, key), get_and_update(t, key, list)], to: Map
defstruct [:id, :name, :avarta_id, :gem, :gold, :last_login, :last_logout]
def new(id) do
%BaseInfo{
id: id,
name: "",
avarta_id: 0,
gem: 0,
gold: 500,
last_login: 0,
last_logout: 0
}
end def add_gem(base_info, num) when is_integer(num) and num > 0 do
{:ok, update_in(base_info, [:gem], &(&1 + num))}
end def cost_gem(base_info, num) when is_integer(num) and num > 0 do
if base_info.gem >= num do
{:ok, update_in(base_info, [:gem], &(&1 - num))}
else
ErrorMsg.gem_not_enough
end
end def add_gold(base_info, num) when is_integer(num) and num > 0 do
{:ok, update_in(base_info, [:gold], &(&1 + num))}
end def cost_gold(base_info, num) when is_integer(num) and num > 0 do
if base_info.gold >= num do
{:ok, update_in(base_info, [:gold], &(&1 - num))}
else
ErrorMsg.gold_not_enough
end
end def set_name(base_info, name), do: %BaseInfo{base_info| name: name}
def set_last_login(base_info, last_login), do: %BaseInfo{base_info| last_login: last_login}
def set_last_logout(base_info, last_logout), do: %BaseInfo{base_info| last_logout: last_logout}
def set_avarta_id(base_info, avarta_id), do: %BaseInfo{base_info| avarta_id: avarta_id} end
defmodule ErrorMsg do
for line <- File.stream!(Path.join([__DIR__, "error_msg.txt"]), [], :line) do
if line |> String.strip |> String.starts_with?("%") do
else
[str_error_atom, str_error_msg] = line |> String.split(",") |> Enum.map(&String.strip(&1))
fun_name = String.to_atom(str_error_atom)
def unquote(fun_name)(), do: {:error, unquote(fun_name), unquote(str_error_msg)}
end
end end
在BaseInfo模块里有用的接口，需要区分操作成功和失败，所以用{:ok, value}和 {:error, :gem_not_enough, "钻石不足"} 等来表示，一开始是
使用模块属性如@gem_not_found {:error, :gem_not_enough}来表示的。这种对于纯erlang或者elixir已经够用了。考虑到需要客户端接入的话，
那么还是需要中文提示之类的，又考虑到有可能错误需要在系统范围内使用。即是以前erlang服务器里定了全局的宏用法。可是elixir没有erlang宏这种东西，模块属性又是编译期用的，没法在别的模块用。所以我构建了ErrorMsg模块，动态从如下外部数据源生成函数供其他模块用。
%% 通用提示
gem_not_enough, 钻石不足
gold_not_enough, 金币不足
另外需要提到的一点，原来使用了update_in 用法，而Access Protocol在我的elixir 版本1.2.3已经废弃了，没法用@derive Access,
所以我搜了网上抄到上述改法（现在不知道会有什么问题）。
最后上简单的测试代码
defmodule BaseInfoTest do
use ExUnit.Case
setup do
base_info = %BaseInfo{ gem: 10, gold: 10}
{:ok, base_info: base_info}
end test "add valid gem", %{base_info: base_info} do
assert {:ok, new_base_info} = base_info |> BaseInfo.add_gem(10)
assert new_base_info.gem == base_info.gem + 10
end test "add invalid gem", %{base_info: base_info} do
assert catch_error(
{:ok, _} = base_info |> BaseInfo.add_gem(-10)
)
end test "add float gem", %{base_info: base_info} do
assert catch_error(
{:ok, _} = base_info |> BaseInfo.add_gem(10.5)
)
end test "cost valid gem", %{base_info: base_info} do
assert {:ok, new_base_info} = base_info |> BaseInfo.cost_gem(10)
assert new_base_info.gem == base_info.gem - 10
end test "cost invalid gem", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.cost_gem(-10)
end test "cost float gem", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.cost_gem(10.5)
end test "cost gem_not_enough", %{base_info: base_info} do
assert ErrorMsg.gem_not_enough == base_info |> BaseInfo.cost_gem(20)
end test "add valid gold", %{base_info: base_info} do
assert {:ok, new_base_info} = base_info |> BaseInfo.add_gold(10)
assert new_base_info.gold == base_info.gold + 10
end test "add invalid gold", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.add_gold(-10)
end test "add float gold", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.add_gold(10.5)
end test "cost valid gold", %{base_info: base_info} do
assert {:ok, new_base_info} = base_info |> BaseInfo.cost_gold(10)
assert new_base_info.gold == base_info.gold - 10
end test "cost invalid gold", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.cost_gold(-10)
end test "cost float gold", %{base_info: base_info} do
assert catch_error base_info |> BaseInfo.cost_gold(10.5)
end test "cost gold_not_enough", %{base_info: base_info} do
assert ErrorMsg.gold_not_enough == base_info |> BaseInfo.cost_gold(20)
end test "set_avarta_id", %{base_info: base_info} do
new_base_info = base_info |> BaseInfo.set_avarta_id(10001)
assert new_base_info.avarta_id == 10001
end end
其他不测了，正式项目，当然还是仔细都测了好。
留下的疑问，在ErrorMsg模块里，不知道如何把生成函数挪到for外面，我试了下没成功。知道的同学留个解决方案
今天到此结束。明天正式建模玩家进程吧。