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made a theme which shows code comments clearer

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Carl Fredrik Samson
2020-02-01 18:42:18 +01:00
parent 315cba6589
commit 95314dd35d
15 changed files with 367 additions and 501 deletions
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book/3_generators_pin.html
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@@ -78,7 +78,7 @@
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
<div class="sidebar-scrollbox">
<ol class="chapter"><li><a href="0_introduction.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li><a href="1_background_information.html"><strong aria-hidden="true">2.</strong> Some background information</a></li><li><a href="2_trait_objects.html"><strong aria-hidden="true">3.</strong> Trait objects and fat pointers</a></li><li><a href="3_generators_pin.html" class="active"><strong aria-hidden="true">4.</strong> Generators and Pin</a></li><li><a href="4_pin.html"><strong aria-hidden="true">5.</strong> Pin</a></li><li><a href="6_future_example.html"><strong aria-hidden="true">6.</strong> The main example</a></li><li><a href="7_conclusion.html"><strong aria-hidden="true">7.</strong> Conclusion and exercises</a></li><li><a href="8_finished_example.html"><strong aria-hidden="true">8.</strong> Finished example (editable)</a></li></ol>
<ol class="chapter"><li class="affix"><a href="introduction.html">Introduction</a></li><li><a href="1_background_information.html"><strong aria-hidden="true">1.</strong> Some background information</a></li><li><a href="2_trait_objects.html"><strong aria-hidden="true">2.</strong> Trait objects and fat pointers</a></li><li><a href="3_generators_pin.html" class="active"><strong aria-hidden="true">3.</strong> Generators and Pin</a></li><li><a href="4_pin.html"><strong aria-hidden="true">4.</strong> Pin</a></li><li><a href="6_future_example.html"><strong aria-hidden="true">5.</strong> The main example</a></li><li><a href="8_finished_example.html"><strong aria-hidden="true">6.</strong> Finished example (editable)</a></li></ol>
</div>
<div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
</nav>
@@ -155,7 +155,7 @@
<ul>
<li>Understanding how the async/await syntax works since it's how <code>await</code> is implemented</li>
<li>Why we need <code>Pin</code></li>
<li>Why Rusts async model is extremely efficient</li>
<li>Why Rusts async model is very efficient</li>
</ul>
<p>The motivation for <code>Generators</code> can be found in <a href="https://github.com/rust-lang/rfcs/blob/master/text/2033-experimental-coroutines.md">RFC#2033</a>. It's very
well written and I can recommend reading through it (it talks as much about
@@ -166,8 +166,8 @@ is Generators and the <code>Pin</code> type. Since they're related we'll start o
exploring generators first. By doing that we'll soon get to see why
we need to be able to &quot;pin&quot; some data to a fixed location in memory and
get an introduction to <code>Pin</code> as well.</p>
<p>Basically, there were three main options that were discussed when Rust was
desiging how the language would handle concurrency:</p>
<p>Basically, there were three main options that were discussed when Rust was
designing how the language would handle concurrency:</p>
<ol>
<li>Stackful coroutines, better known as green threads.</li>
<li>Using combinators.</li>
@@ -213,7 +213,7 @@ the needed state increases with each added step.</p>
<h3><a class="header" href="#stackless-coroutinesgenerators" id="stackless-coroutinesgenerators">Stackless coroutines/generators</a></h3>
<p>This is the model used in Rust today. It a few notable advantages:</p>
<ol>
<li>It's easy to convert normal Rust code to a stackless corotuine using using
<li>It's easy to convert normal Rust code to a stackless coroutine using using
async/await as keywords (it can even be done using a macro).</li>
<li>No need for context switching and saving/restoring CPU state</li>
<li>No need to handle dynamic stack allocation</li>
@@ -268,7 +268,6 @@ compiled to something looking similar to this:</p>
// If you've ever wondered why the parameters are called Y and R the naming from
// the original rfc most likely holds the answer
enum GeneratorState&lt;Y, R&gt; {
// originally called `CoResult`
Yielded(Y), // originally called `Yield(Y)`
Complete(R), // originally called `Return(R)`
}
@@ -335,7 +334,7 @@ limitation just slip and call it a day yet.</p>
<p>Instead of discussing it in theory, let's look at some code. </p>
<blockquote>
<p>We'll use the optimized version of the state machines which is used in Rust today. For a more
in deapth explanation see <a href="https://tmandry.gitlab.io/blog/posts/optimizing-await-1/">Tyler Mandry's execellent article: How Rust optimizes async/await</a></p>
in deapth explanation see <a href="https://tmandry.gitlab.io/blog/posts/optimizing-await-1/">Tyler Mandry's excellent article: How Rust optimizes async/await</a></p>
</blockquote>
<pre><code class="language-rust noplaypen ignore">let a = 4;
let b = move || {
@@ -472,7 +471,7 @@ impl Generator for GeneratorA {
*self = GeneratorA::Yield1 {to_borrow, borrowed: std::ptr::null()};
match self {
GeneratorA::Yield1{to_borrow, borrowed} =&gt; *borrowed = to_borrow,
_ =&gt; ()
_ =&gt; unreachable!(),
};
GeneratorState::Yielded(res)
@@ -592,7 +591,7 @@ impl Generator for GeneratorA {
*this = GeneratorA::Yield1 {to_borrow, borrowed: std::ptr::null()};
match this {
GeneratorA::Yield1{to_borrow, borrowed} =&gt; *borrowed = to_borrow,
_ =&gt; ()
_ =&gt; unreachable!(),
};
GeneratorState::Yielded(res)
@@ -617,7 +616,7 @@ the value afterwards it will violate the guarantee they promise to uphold when
they did their unsafe implementation.</li>
</ol>
<p>Now, the code which is created and the need for <code>Pin</code> to allow for borrowing
across <code>yield</code> points should be pretty clear. </p>
across <code>yield</code> points should be pretty clear.</p>
</main>
@@ -657,6 +656,21 @@ across <code>yield</code> points should be pretty clear. </p>
</div>
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