Update tutorial to use basic-cli URLs

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Richard Feldman 2022-11-26 17:44:33 -05:00
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@ -175,20 +175,16 @@ to use them for more than that.</p>
<p>Let's move out of the REPL and create our first Roc application!</p> <p>Let's move out of the REPL and create our first Roc application!</p>
<p>Make a file named <code>main.roc</code> and put this in it:</p> <p>Make a file named <code>main.roc</code> and put this in it:</p>
<samp><span class="kw">app</span> <span class="str">"hello"</span> <samp><span class="kw">app</span> <span class="str">"hello"</span>
<span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"examples/cli/cli-platform/main.roc"</span> <span class="brace">}</span> <span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
<span class="kw">imports</span> <span class="brace">[</span>pf.Stdout<span class="brace">]</span> <span class="kw">imports</span> <span class="brace">[</span>pf.Stdout<span class="brace">]</span>
<span class="kw">provides</span> <span class="brace">[</span>main<span class="brace">]</span> <span class="kw">to</span> pf <span class="kw">provides</span> <span class="brace">[</span>main<span class="brace">]</span> <span class="kw">to</span> pf
main <span class="kw">=</span> main <span class="kw">=</span>
Stdout.line <span class="str">"I'm a Roc application!"</span> Stdout.line <span class="str">"I'm a Roc application!"</span>
</samp> </samp>
<p>In order to get access to this <code>examples/cli/cli-platform/main.roc</code> file, you'll need
to download the <a href="https://github.com/roc-lang/roc">Roc source code repository</a>, which
contains the <code>examples</code> directory at the beginning of that string. Make sure you <code>cd</code>
into that directory once you've downloaded it!</p>
<p>Try running this with:</p> <p>Try running this with:</p>
<samp>roc dev</samp> <samp>roc dev</samp>
<p>You should see this printed to the terminal:</p> <p>You should a see a message about a file being downloaded, followed by this:</p>
<samp>I'm a Roc application!</samp> <samp>I'm a Roc application!</samp>
<p>Congratulations - you've written your first Roc application! We'll go over what the parts of <p>Congratulations - you've written your first Roc application! We'll go over what the parts of
this file above <code>main</code> do later, but first let's play around a bit.</p> this file above <code>main</code> do later, but first let's play around a bit.</p>
@ -203,7 +199,9 @@ total <span class="kw">=</span> Num.toStr <span class="paren">(</span>birds <spa
main <span class="kw">=</span> main <span class="kw">=</span>
Stdout.line <span class="str">"There are <span class="str-esc">\(</span><span class="str-interp">total</span><span class="str-esc">)</span> animals."</span> Stdout.line <span class="str">"There are <span class="str-esc">\(</span><span class="str-interp">total</span><span class="str-esc">)</span> animals."</span>
</samp> </samp>
<p>Now if you run <code>roc dev</code>, you should see this:</p> <p>Now run <code>roc dev</code> again. This time the "Downloading …" message won't appear;
the file has been cached from last time, and won't need to be downloaded again.</p>
<p>You should see this:</p>
<samp>There are 5 animals.</samp> <samp>There are 5 animals.</samp>
<p><code>main.roc</code> now has four definitions—<em>defs</em> for <p><code>main.roc</code> now has four definitions—<em>defs</em> for
short—<code>birds</code>, <code>iguanas</code>, <code>total</code>, and <code>main</code>.</p> short—<code>birds</code>, <code>iguanas</code>, <code>total</code>, and <code>main</code>.</p>
@ -367,8 +365,16 @@ because <code>total</code> is calling <code>addAndStringify</code> passing a rec
<h3 id="comments"><a href="#comments">Comments</a></h3> <h3 id="comments"><a href="#comments">Comments</a></h3>
<p>By the way, this is a comment in Roc:</p> <p>By the way, this is a comment in Roc:</p>
<samp class="comment"># The `name` field is unused by addAndStringify</samp> <samp class="comment"># The `name` field is unused by addAndStringify</samp>
<p>Whenever you write <span class="comment">#</span> it means that the rest of the line is a comment, <p>Whenever you write <code>#</code> it means that the rest of the line is a comment,
and will have no effect on the program.</p> and will not affect the program.</p>
<h3 id="doc-comments"><a href="#doc-comments">Doc Comments</a></h2>
<p>Comments that begin with <code>##</code> will be included in generated documentation (<code>roc docs</code>). They can include code blocks by adding five spaces after <code>##</code>. </p>
<samp><span class="comment">## This is a comment for documentation, and includes a <span class="kw">code</span> block.</span>
<span class="comment">##</span>
<span class="comment">## x <span class="op">=</span> <span class="number">2</span></span>
<span class="comment">## expect x <span class="op">==</span> <span class="number">2</span></span>
</samp>
<p>Roc does not have multiline comment syntax.</p>
<h3 id="record-shorthands"><a href="#record-shorthands">Record shorthands</a></h3> <h3 id="record-shorthands"><a href="#record-shorthands">Record shorthands</a></h3>
<p>Roc has a couple of shorthands you can use to express some record-related operations more concisely.</p> <p>Roc has a couple of shorthands you can use to express some record-related operations more concisely.</p>
<p>Instead of writing <code>\record -&gt; record.x</code> we can write <code>.x</code> and it will evaluate to the same thing: <p>Instead of writing <code>\record -&gt; record.x</code> we can write <code>.x</code> and it will evaluate to the same thing:
@ -1231,7 +1237,7 @@ Roc compiler. That's why they're called "builtins!"</p>
<h2 id="the-app-module-header"><a href="#the-app-module-header">The app module header</a></h2> <h2 id="the-app-module-header"><a href="#the-app-module-header">The app module header</a></h2>
<p>Let's take a closer look at the part of <code>main.roc</code> above the <code>main</code> def:</p> <p>Let's take a closer look at the part of <code>main.roc</code> above the <code>main</code> def:</p>
<samp><span class="hljs-selector-tag">app</span> "<span class="hljs-selector-tag">hello</span>" <samp><span class="hljs-selector-tag">app</span> "<span class="hljs-selector-tag">hello</span>"
<span class="hljs-selector-tag">packages</span> { <span class="attribute">pf</span>: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
<span class="hljs-selector-tag">imports</span> <span class="hljs-selector-attr">[pf.Stdout]</span> <span class="hljs-selector-tag">imports</span> <span class="hljs-selector-attr">[pf.Stdout]</span>
<span class="hljs-selector-tag">provides</span> <span class="hljs-selector-tag">main</span> <span class="hljs-selector-tag">to</span> <span class="hljs-selector-tag">pf</span> <span class="hljs-selector-tag">provides</span> <span class="hljs-selector-tag">main</span> <span class="hljs-selector-tag">to</span> <span class="hljs-selector-tag">pf</span>
</samp> </samp>
@ -1244,13 +1250,18 @@ means when you run <code>roc dev</code>, the Roc compiler will build an executab
named <code>hello</code> (or <code>hello.exe</code> on Windows) and run it. You can also build the executable named <code>hello</code> (or <code>hello.exe</code> on Windows) and run it. You can also build the executable
without running it by running <code>roc build</code>.</p> without running it by running <code>roc build</code>.</p>
<p>The remaining lines all involve the <em>platform</em> this application is built on:</p> <p>The remaining lines all involve the <em>platform</em> this application is built on:</p>
<samp><span class="hljs-selector-tag">packages</span> { <span class="attribute">pf</span>: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <samp><span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
<span class="hljs-selector-tag">imports</span> <span class="hljs-selector-attr">[pf.Stdout]</span> <span class="kw">imports</span> <span class="brace">[</span>pf.Stdout<span class="brace">]</span>
<span class="hljs-selector-tag">provides</span> <span class="hljs-selector-tag">main</span> <span class="hljs-selector-tag">to</span> <span class="hljs-selector-tag">pf</span> <span class="kw">provides</span> <span class="brace">[</span>main<span class="brace">]</span> <span class="kw">to</span> pf
</samp> </samp>
<p>The <code>packages { pf: "examples/cli/cli-platform/main.roc" }</code> part says two things:</p> <p>The <code>packages { pf: "https://…tar.br" }</code> part says three things:</p>
<ul> <ul>
<li>We're going to be using a <em>package</em> (that is, a collection of modules) called <code>"examples/cli/cli-platform/main.roc"</code></li> <li>We're going to be using a <em>package</em> (that is, a collection of modules) that can be downloaded from the URL <code>"https://…tar.br"</code></li>
<li>That package's <a href="https://en.wikipedia.org/wiki/Base64#URL_applications">base64url</a>-encoded <a href="https://en.wikipedia.org/wiki/BLAKE_(hash_function)#BLAKE3">BLAKE3</a>
cryptographic hash is the long string at the end (before the <code>.tar.br</code> file extension).
Once the file has been downloaded, its contents will be verified against this hash, and it will only
be installed if they match. (This way, you can be confident the download was neither corrupted nor
changed since it was originally published.)</li>
<li>We're going to name that package <code>pf</code> so we can refer to it more concisely in the future.</li> <li>We're going to name that package <code>pf</code> so we can refer to it more concisely in the future.</li>
</ul> </ul>
<p>The <code>imports [pf.Stdout]</code> line says that we want to import the <code>Stdout</code> module <p>The <code>imports [pf.Stdout]</code> line says that we want to import the <code>Stdout</code> module
@ -1263,34 +1274,15 @@ at that again:</p>
calling a function named <code>line</code> which is exposed by a module named calling a function named <code>line</code> which is exposed by a module named
<code>Stdout</code>. <code>Stdout</code>.
<p>When we write <code>imports [pf.Stdout]</code>, it specifies that the <code>Stdout</code> <p>When we write <code>imports [pf.Stdout]</code>, it specifies that the <code>Stdout</code>
module comes from the <code>pf</code> package.</p> module comes from the package we named <code>pf</code> in the <code>packages { pf: … }</code> section.</p>
<p>Since <code>pf</code> was the name we chose for the <code>examples/cli/cli-platform/main.roc</code>
package (when we wrote <code>packages { pf: "examples/cli/cli-platform/main.roc" }</code>),
this <code>imports</code> line tells the Roc compiler that when we call <code>Stdout.line</code>, it
should look for that <code>line</code> function in the <code>Stdout</code> module of the
<code>examples/cli/cli-platform/main.roc</code> package.</p>
<p>If we would like to include other modules in our application, say <code>AdditionalModule.roc</code> and <code>AnotherModule.roc</code>, then they can be imported directly in <code>imports</code> like this: </p> <p>If we would like to include other modules in our application, say <code>AdditionalModule.roc</code> and <code>AnotherModule.roc</code>, then they can be imported directly in <code>imports</code> like this: </p>
<samp><span class="hljs-selector-tag">packages</span> { <span class="attribute">pf</span>: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <samp><span class="kw">imports</span> <span class="brace">[</span>pf.Stdout<span class="comma">,</span> AdditionalModule<span class="comma">,</span> AnotherModule<span class="brace">]</span></span>
<span class="hljs-selector-tag">imports</span> <span class="hljs-selector-attr">[pf.Stdout, AdditionalModule, AnotherModule]</span>
<span class="hljs-selector-tag">provides</span> <span class="hljs-selector-tag">main</span> <span class="hljs-selector-tag">to</span> <span class="hljs-selector-tag">pf</span>
</samp> </samp>
<h2 id="comments"><a href="#comments">Comments</a></h2>
<p>Comments that begin with <code>##</code> will be included in generated documentation (<code>roc docs</code>). They require a single space after the <code>##</code>, and can include code blocks by adding five spaces after <code>##</code>. </p>
<samp><span class="comment">## This is a comment for documentation, and includes a <span class="kw">code</span> block.</span>
<span class="comment">##</span>
<span class="comment">## x <span class="op">=</span> <span class="number">2</span></span>
<span class="comment">## expect x <span class="op">==</span> <span class="number">2</span></span>
</samp>
<p>Roc also supports inline comments and line comments with <code>#</code>. They can be used to add information that won't be included in documentation.</p>
<samp><span class="comment"># This is a line comment that won't appear in documentation.</span>
myFunction : U8<span class="hljs-function"> <span class="op">-&gt;</span> U8
myFunction <span class="op">=</span> <span class="str">\bit</span> <span <span class="opclass="hljs-function">-&gt;<</span>/span> bit % <span class="number">2</span> <span class="comment"># this is an inline comment</span>
</samp>
<p>Roc does not have multiline comment syntax.</p>
<h2 id="tasks"><a href="#tasks">Tasks</a></h2> <h2 id="tasks"><a href="#tasks">Tasks</a></h2>
<p>Tasks are technically not part of the Roc language, but they're very common in <p>Tasks are technically not part of the Roc language, but they're very common in
platforms. Let's use the CLI platform in <code>examples/cli/cli-platform/main.roc</code> as an example!</p> platforms. Let's continue using the <a href="https://github.com/roc-lang/basic-cli">basic-cli</a> platform
<p>In the CLI platform, we have four operations we can do:</p> we've been using up to this point as an example!</p>
<p>In the <code>basic-cli</code> platform, we have four operations we can do:</p>
<ul> <ul>
<li>Write a string to the console</li> <li>Write a string to the console</li>
<li>Read a string from user input</li> <li>Read a string from user input</li>
@ -1298,9 +1290,9 @@ platforms. Let's use the CLI platform in <code>examples/cli/cli-platform/main.ro
<li>Read a string from a file</li> <li>Read a string from a file</li>
</ul> </ul>
<p>We'll use these four operations to learn about tasks.</p> <p>We'll use these four operations to learn about tasks.</p>
<p>First, let's do a basic "Hello World" using the tutorial app.</p> <p>Let's start with a basic "Hello World" program.</p>
<samp><span class="kw">app</span> <span class="str">"cli-tutorial"</span> <samp><span class="kw">app</span> <span class="str">"cli-tutorial"</span>
packages { pf: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
imports [pf.Stdout] imports [pf.Stdout]
provides [main] to pf provides [main] to pf
@ -1325,7 +1317,7 @@ when it runs (hence the <code>*</code>).</p>
</samp> </samp>
<p>Let's change <code>main</code> to read a line from <code>stdin</code>, and then print it back out again:</p> <p>Let's change <code>main</code> to read a line from <code>stdin</code>, and then print it back out again:</p>
<samp>app <span class="str">"cli-tutorial"</span> <samp>app <span class="str">"cli-tutorial"</span>
packages { pf: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
imports [pf.Stdout, pf.Stdin, pf.Task] imports [pf.Stdout, pf.Stdin, pf.Task]
provides [main] to pf provides [main] to pf
@ -1360,7 +1352,7 @@ the program isn't doing anything when we start it up:</p>
</samp> </samp>
<p>This works, but we can make it a little nicer to read. Let's change it to the following:</p> <p>This works, but we can make it a little nicer to read. Let's change it to the following:</p>
<samp>app <span class="str">"cli-tutorial"</span> <samp>app <span class="str">"cli-tutorial"</span>
packages { pf: <span class="str">"examples/cli/cli-platform/main.roc"</span> } <span class="kw">packages</span> <span class="brace">{</span> pf: <span class="str">"https://github.com/roc-lang/basic-cli/releases/download/0.1.0/_V6HO2Dwez0xsSstgK8qC6wBLXSfNlVFyUTMg0cYiQQ.tar.br"</span> <span class="brace">}</span>
imports [pf.Stdout, pf.Stdin, pf.Task.{ await }] imports [pf.Stdout, pf.Stdin, pf.Task.{ await }]
provides [main] to pf provides [main] to pf