把erlang的helloworld代码敲了两遍，对erlang的理解有了初步的认识，比如，erlang的尾递归，代替循环之类。我把我敲的erlang的helloworld代码贴出来先，后面有时间，我再来补点注释。
Coding helloworld by erlang
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-module(helloworld).
-export([hw/0]).
-export([hw3/1]).
-export([hw5/1]).
-export([hw6/1]).
-export([hw7/1]).
-export([hw8/1]).
-export([hw9/1]).
-export([hw10/0]).
-export([hw11/0]).
-export([hw12/0]).
-export([hw14/0]).
-export([hw13/0]).
-export([hw15/0]).
-export([hw16/0]).
-export([hw16b/0]).
-export([hw18/0]).
hw() -> io:format("Hello World!! ~n").
hw3(N) when N > 0 ->
io:format("Hello World!! ~n"),
hw3(N-1);
hw3(0) -> ok.
hw5(N) ->
case N of
X when X > 0 ->
io:format("Hello World ~n"),
hw5(N-1);
0 -> ok
end.
hw6(N) ->
if
N > 0 ->
io:format("Hello World ~n"),
hw5(N-1);
N == 0 ->
ok
end.
hw7(N) ->
[hw() || _ <- lists:seq(1, N) ].
for(I, N, F) when I < N ->
F(),
for(I + 1, N, F);
for(N, N, F) ->
F().
hw8(N) ->
for(1, N, fun hw/0).
hw9(N) ->
for(1, N, fun() -> hw() end).
hw(Who) ->
io:format("Hello ~p ~n", [Who]).
hw10(L) ->
[hw(X) || X <- L].
hw10() ->
L = ["ali", "mark", "bob", "cat"],
hw10(L).
hw11(L) ->
lists:map(fun hw/1, L).
hw11() ->
L = ["mac", "ios", "dog", "anne"],
hw11(L).
hw14(L) ->
lists:foreach(fun hw/1, L).
hw14() ->
L = ["hall", "book", "cup"],
hw14(L).
hw12([H|T]) ->
hw(H),
hw12(T);
hw12([]) ->
ok.
hw12() ->
L = ["teacher", "student", "Head"],
hw12(L).
hw13(L) ->
case L of
[] -> ok;
[H|T] -> hw(H),
hw13(T)
end.
hw13() ->
L = ["iPhone", "android", "eye", "hand"],
hw13(L).
hw15srv() ->
receive
{name, Name} ->
io:format("Hello ~p ~n", [Name]),
hw15srv()
end.
hw15() ->
Pid = spawn(fun hw15srv/0),
Pid ! {name, "alice"},
Pid ! {name, "Bob"}.
hw16srv() ->
receive
{From, {name, Name}} ->
io:format("Server recive: ~p ~n", [Name]),
From ! {self(), {reply, "Welcome, " ++ Name}},
hw16srv()
end.
hw16() ->
Pid = spawn(fun hw16srv/0),
Sid = self(),
Pid ! {Sid, {name, "alice"}},
receive
{Pid, {reply, Msg}} ->
io:format("Client receive: ~p ~n", [Msg])
end.
rpc(Pid, Request) ->
Pid ! {self(), Request},
receive
{Pid, Response} ->
Response
end.
hw16b() ->
Pid = spawn(fun hw16srv/0),
{reply, Reply} = rpc(Pid, {name, "alice"}),
io:format("Client receive: ~p ~n", [Reply]).
rpc2(Pid, Request) ->
Ref = make_ref(),
Pid ! {{self(), Ref}, Request},
receive
{Ref, Reply} ->
Reply
end.
hw18srv() ->
receive
{{From, Ref}, {name, Name}} ->
io:format("Server receive: ~p ~n", [Name]),
From ! {Ref, {reply, "Welcome, " ++ Name}},
hw16srv()
end.
hw18() ->
Pid = spawn(fun hw18srv/0),
{reply, Reply} = rpc2(Pid, {name, "alice"}),
io:format("Client receive: ~p ~n", [Reply]).