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author Franklin Schmidt <fschmidt@gmail.com>
date Tue, 22 Mar 2022 09:00:59 -0700
parents 13135e289b50
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1646:1828ed4ee75d 1647:7eddf1e990c0
47 47
48 <p>In Luan, a function call with one string argument doesn't require parenthesis, so <b>print("Hello World")</b> is the same as <b>print "Hello World"</b> and <b>require "luan:Io.luan"</b> is the same as <b>require("luan:Io.luan")</b>. Both <b>require</b> and <b>print</b> are functions.</p> 48 <p>In Luan, a function call with one string argument doesn't require parenthesis, so <b>print("Hello World")</b> is the same as <b>print "Hello World"</b> and <b>require "luan:Io.luan"</b> is the same as <b>require("luan:Io.luan")</b>. Both <b>require</b> and <b>print</b> are functions.</p>
49 49
50 <p>The <b>require</b> function takes a <a href="http://en.wikipedia.org/wiki/Uniform_resource_identifier">URI</a> as an argument. Examples of URIs are "<b>luan:Io.luan</b>" and "<b>file:hello.luan</b>". <b>require</b> is used to import a module, which is returned from the <b>require</b> function call. In the case above, we assign the module to the local variable <b>Io</b>. The function <b>print</b> is a member of this module. We could have done <b>Io.print("Hello World")</b> but instead we chose to assign <b>print</b> to a local variable and use that to call the function.</p> 50 <p>The <b>require</b> function takes a <a href="http://en.wikipedia.org/wiki/Uniform_resource_identifier">URI</a> as an argument. Examples of URIs are "<b>luan:Io.luan</b>" and "<b>file:hello.luan</b>". <b>require</b> is used to import a module, which is returned from the <b>require</b> function call. In the case above, we assign the module to the local variable <b>Io</b>. The function <b>print</b> is a member of this module. We could have done <b>Io.print("Hello World")</b> but instead we chose to assign <b>print</b> to a local variable and use that to call the function.</p>
51 51
52 <p>Luan starts with only two defined functions: <b>require</b> and <b>java</b>. You will use <b>require</b> to import whatever you need. This is a little more work, but makes it clear in each file where each function comes from.</p> 52 <p>Luan starts with only one defined function: <b>require</b>. You will use <b>require</b> to import whatever you need. This is a little more work, but makes it clear in each file where each function comes from.</p>
53 53
54 <p>Let's a make fancier version:</p> 54 <p>Let's a make fancier version:</p>
55 55
56 <pre> 56 <pre>
57 local Io = require "luan:Io.luan" 57 local Io = require "luan:Io.luan"
64 hello("Bob") 64 hello("Bob")
65 </pre> 65 </pre>
66 66
67 <p>The <b>..</b> operator does concatenation. This will print <b>Hello Bob</b>.</p> 67 <p>The <b>..</b> operator does concatenation. This will print <b>Hello Bob</b>.</p>
68 68
69 <p>Now let's make a web page. First we need a directory for our website. So create a directory <b>site</b>. In this directory, create a file <b>hi.html.luan</b> containing: 69 <p>Now let's make a web page. First we need a directory for our website. So create a directory <b>src</b>. In this directory, create a file <b>hi.html.luan</b> containing:
70 70
71 <pre> 71 <pre>
72 local Io = require "luan:Io.luan" 72 local Io = require "luan:Io.luan"
73 local Http = require "luan:http/Http.luan" 73 local Http = require "luan:http/Http.luan"
74 74
83 &lt;/html> 83 &lt;/html>
84 <% 84 <%
85 end 85 end
86 </pre> 86 </pre>
87 87
88 <p>Now go back to the parent directory and do <b>luan luan:http/serve.luan file:site</b>. This will run the Luan web server on port 8080. Try going to <a href="http://localhost:8080/">http://localhost:8080/</a>. You should see the directory. If you click on <b>hi.html.luan</b> you will see the source. But if you remove the <b>.luan</b> and just go to <a href="http://localhost:8080/hi.html">http://localhost:8080/hi.html</a> then you will run the program which will generate the web page.</p> 88 <p>Now go back to the parent directory and do <b>luan luan:http/serve.luan src</b>. This will run the Luan web server on port 8080. Try going to <a href="http://localhost:8080/">http://localhost:8080/</a>. You should see the directory. If you click on <b>hi.html.luan</b> you will see the source. But if you remove the <b>.luan</b> and just go to <a href="http://localhost:8080/hi.html">http://localhost:8080/hi.html</a> then you will run the program which will generate the web page.</p>
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90 <p>The Luan webserver expects the file to return a function and calls it to generate the page. Code of the form <b>%>...<%</b> writes its output to <b>Io.stdout</b> which by default is the standard output of the command line. So in the returned function one usually starts by setting <b>Io.stdout</b> to a <code>text_writer</code> which writes its output to the HTTP response (to the web browser).</p> 90 <p>The Luan webserver expects the file to return a function and calls it to generate the page. Code of the form <b>%>...<%</b> writes its output to <b>Io.stdout</b> which by default is the standard output of the command line. So in the returned function one usually starts by setting <b>Io.stdout</b> to a <code>text_writer</code> which writes its output to the HTTP response (to the web browser).</p>
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92 <p>You can find this example and others in the <a href="examples/">examples directory</a>. Take a look at <a href="examples/hi2.luan">hi2.luan</a> next. Remember to remove the <b>.luan</b> from the URL to run the code.</p> 92 <p>You can find this example and others in the <a href="examples/">examples directory</a>. Take a look at <a href="examples/hi2.luan">hi2.luan</a> next. Remember to remove the <b>.luan</b> from the URL to run the code.</p>
93 93
94 <p>So now you have built your website and you want to publish it to the web. If you have your own domain, create a CNAME record for it pointing to <b>s1.luan.software</b>. If you don't have a domain, just use a domain like <b>bob.s1.luan.software</b> (anything of the form <b>*.s1.luan.software</b>). Assuming your directory is <b>site</b> and you will use the password <b>secret</b>, do the following from the command line: 94 <p>So now you have built your website and you want to publish it to the web. If you have your own domain, create a CNAME record for it pointing to <b>s1.luan.software</b>. If you don't have a domain, just use a domain like <b>bob.s1.luan.software</b> (anything of the form <b>*.s1.luan.software</b>). Assuming your directory is <b>src</b> and you will use the password <b>secret</b>, do the following from the command line:
95 95
96 <pre> 96 <pre>
97 luan luan:host/push.luan bob.s1.luan.software secret site 97 luan luan:host/push.luan bob.s1.luan.software secret src
98 </pre> 98 </pre>
99 99
100 <p>The form is <b>luan luan:host/push.luan domain password directory</b>. If you change your site, just run this again and your site will be updated. To delete your site, do <b>luan luan:host/delete.luan domain password</b>.</p> 100 <p>The form is <b>luan luan:host/push.luan domain password directory</b>. If you change your site, just run this again and your site will be updated. To delete your site, do <b>luan luan:host/delete.luan domain password</b>.</p>
101 101
102 <p>Hopefully this short tutorial gave you an idea of how to use Luan to make a website.</p> 102 <p>Hopefully this short tutorial gave you an idea of how to use Luan to make a website.</p>