http://oscardelben.com/seven-languages-io-day-1
我刚买了Seven languages in seven weeks这本书的Beta版，真是一本好书。
这本书每章介绍一门编程语言，总共是七门语言。每章你都能找到语言的介绍，还有一些练习和自学题目。实际上每章也分成三天，我将用“第一天”“第二天”“第三天”来写它们。
这本书里介绍了下面这些编程语言：
Ruby
IOLanguage
Prolog
Scala
Erlang
Clujure
Haskell
因为我（原作者）知道ruby了，就很快翻到第二章IOLanguage。IO是一门原型编程语言，某种程度上类似javascript（译者注：类似语言还有Lua）。我喜欢这门语言的语法和简洁性。
在Mac os X上安装IO
如果你想编译所有依赖库，从源代码开始安装需要一些时间。这里我们使用macports来获取所有依赖库，你可以在这里http://www.iolanguage.com/scm/io/docs/IoGuide.html#Introduction-Installing找到详细的安装文档。
1: cd ~/
2: git clone git://github.com/stevedekorte/io.git
3: cd io
4: make vm; sudo make install; sudo make port; sudo make install
你可能不得不加入一些辅助库，可以参考前面关于安装的在线文档知道详细步骤。
如果你想安装textmate的绑定，可以运行以下命令：
1: cd "/Library/Application Support/TextMate/Bundles"
2: svn co http://svn.textmate.org/trunk/Bundles/Io.tmbundle/
就是这些，现在可以运行Terminal程序了。
IO语言基础
IO编程语言的完整介绍可以参考这里http://www.iolanguage.com/scm/io/docs/IoGuide.html
下面是一个简单的预览：
1: Io 20090105
2:
3: Io> 3 * 4
4: ==> 12
5:
6: Io> Animal := Object clone
7: ==> Animal_0x10034c170:
8: type = "Animal"
9:
10:
11: Io> Animal description := "All animals in the world"
12: ==> All animals in the world
13:
14: Io> dog := Animal clone
15: ==> Animal_0x10033f5f0:
16:
17: Io> dog description
18: ==> All animals in the world
19:
20: Io> dog description := "A generic dog"
21: ==> A generic dog
22:
23: Io> dog description
24: ==> A generic dog
25:
26: Io> dog talk := method("Baw" print)
27: ==> method(
28: "Baw" print
29: )
30:
31: Io> dog talk()
32: Baw==> Baw
33:
34: Io> list(1, 2, 3) sum
35: ==> 6
36:
37: Io> list(1, 2, 3) average
38: ==> 2
39:
40: Io> list(1, 2, 3) map(x, x * x)
41: ==> list(1, 4, 9)
42:
43: Io> fibonacci := method(n, if(n < 2, n, (fibonacci(n -1) + fibonacci(n - 2))))
44: ==> method(n,
45: if(n < 2, n, (fibonacci(n - 1) + fibonacci(n - 2)))
46: )
47: Io> fibonacci(34)
48: ==> 5702887
先别担心这语言看上去有些怪异，实际上你会发现它的语法非常简单。
通过IO建立一个在线新闻程序
这是我做的一个小练习，刚刚学过语言以后，用IO语言在20分钟内创建一个简单版本的新闻平台。代码不是很出彩，但是它证明了使用IO多轻松简单。
1: # INSTANTIATE DB
2:
3: db := SQLite clone
4: db setPath("news.sqlite")
5:
6: # HTML HELPERS
7:
8: ul := method(content, "<ul>" .. content .. "</ul>")
9:
10: li := method(content, "<li>".. content .. "</li>")
11:
12: a := method(text, url, "<a href=\"#{url}\">#{text}</a>" interpolate)
13:
14: form := method(action, content, "<form action=\"#{action}\" method=\"get\">" interpolate .. content .. "</form>")
15:
16: field := method(name, "<label>#{name}</label>: <input type=\"text\" name=\"#{name}\" \>" interpolate)
17:
18: submit := method("<input type=\"submit\" />")
19:
20: with_template := method(title, body,
21: "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\"
22: \"http://www.w3.org/TR/html4/loose.dtd\">
23: <html>
24: <head>
25: <meta http-equiv=\"Content-type\" content=\"text/html; charset=utf-8\">
26: <title>" .. title .. "</title>
27: <style type=\"text/css\" media=\"screen\">
28: body {
29: background:#ffffcc;
30: margin:20px;
31: padding:0;
32: font-family:Calibri;
33: font-size:18px;
34: }
35:
36: h1 {
37: color:#006363;
38: margin:1em;
39: }
40:
41: a {
42: color:#ff7373;
43: font-size:20px;
44: }
45:
46: li {
47: line-height:1.5em;
48: }
49: </style>
50: </head>
51: <body>" .. a("Home", "/") .. " - " .. a("New", "/new") .. "<h1>" .. title .. "</h1>" .. body .. "</body></html>"
52: )
53:
54: # Actions
55:
56: render_index := method(params,
57: db open
58: posts := db exec("SELECT * from posts")
59: db close
60:
61: posts_html := posts map(post, li( a( post at("title"), post at("url") ) ) ) join
62:
63: with_template("Io News", ul(posts_html))
64: )
65:
66: render_new := method(params,
67: with_template("New", form("/create", field("title") .. field("url") .. submit() ))
68: )
69:
70: render_create := method(params,
71: db open
72: db exec("INSERT into posts (title, url)
73: values ('#{params at(\"title\")}', '#{params at(\"url\")}')" interpolate)
74: db close
75: with_template("Hurray!", "Io rocks!")
76: )
77:
78: not_found := method(
79: with_template("Not found")
80: )
81:
82: # Unfortunately I had to manually extract the parameters
83:
84: extract_parameters := method(string,
85: # foo=bar&x=y => list(list("foo", "bar"), list("x", "y"))
86: l := string split("&") map(param, param split("="))
87:
88: params := Map clone
89: l foreach(param, params atPut(param at(0), param at(1)))
90: params
91: )
92:
93: handle_request := method(request,
94: path_and_parameters := request split("?")
95: path := path_and_parameters at(0)
96:
97: if(path_and_parameters size > 1,
98: parameters := extract_parameters(path_and_parameters at(1)),
99: parameters := nil
100: )
101:
102: # Does anyone know how to implement cond()?
103: if(path == "/",
104: render_index(parameters),
105: if(path == "/new",
106: render_new(parameters),
107: if(path == "/create",
108: render_create(parameters),
109: not_found
110: )
111: )
112: )
113: )
114:
115: WebRequest := Object clone do(
116: handleSocket := method(aSocket,
117: aSocket streamReadNextChunk
118: request := aSocket readBuffer betweenSeq("GET ", " HTTP")
119: aSocket streamWrite(handle_request(request))
120: aSocket close
121: )
122: )
123:
124: WebServer := Server clone do(
125: setPort(8000)
126: handleSocket := method(aSocket,
127: WebRequest clone @handleSocket(aSocket)
128: )
129: )
130:
131: WebServer start
如果你想运行代码，你可能需要先建立一个数据库结构，下面是我的步骤：
1: db := SQLite clone
2: db setPath("news.sqlite")
3: db open
4: db exec("CREATE TABLE posts(id INTEGER PRIMARY KEY ASC,
5: title VARCHAR(255),
6: url VARCHAR(255),
7: published_at DATE)")
8:
9: db exec("INSERT INTO posts (title, url, published_at)
10: values
11: ('Welcome aboard', 'http://example.com', DATETIME('NOW'))")
12:
13: db exec("INSERT INTO posts (title, url, published_at)
14: values
15: ('Io documentation', 'http://www.iolanguage.com/scm/io/docs/IoGuide.html', DATETIME('NOW'))")
16:
17: db close
结果如下：
个人而言，我非常喜欢IO语言，我可能会多学习它几天时间。
《“[Translate] 七天学习七门编程语言IOLanguage第一天”》 有 1 条评论
书名是七周学习七门程序语言吧～～～