From 8ac9a2f752fe2c66b611b286d9215523c48ad05c Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Sat, 7 Dec 2019 21:59:34 -0500
Subject: more docs

---
 README.html | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 64 insertions(+), 1 deletion(-)

(limited to 'README.html')

diff --git a/README.html b/README.html
index fe1fd75..e34ab71 100644
--- a/README.html
+++ b/README.html
@@ -28,4 +28,67 @@ it is nearly as fast in theory.</p>
 
 <p><code>tests</code> has some test programs written in <code>toc</code>.</p>
 
-<p>To compile the compiler on a Unix-y system, use</p>
+<p>To compile the compiler on a Unix-y system, just run <code>build.sh</code>. You can supply a compiler by running <code>CC=tcc build.sh</code>, or built it in release mode with <code>./build.sh release</code> (which will help speed up compiling large programs). </p>
+
+<p>On other systems, you can just compile main.c with a C compiler. toc uses several C99 and a couple of C11 features, so it might not work on all compilers. But it does compile on quite a few, including <code>clang</code>, <code>gcc</code>, and <code>tcc</code>. It can also be compiled as if it were C++, but it does break the standard in a few places*. So, MSVC can also compile it. The <em>outputted</em> code should be C99-compliant.</p>
+
+<hr />
+
+<h3><code>toc</code> Source Code</h3>
+
+<p><code>toc</code> is written in C, for speed and portability. It has no dependencies, other than the C runtime library.</p>
+
+<h4>Build system</h4>
+
+<p><code>toc</code> is set up as a unity build, meaning that there is only one translation unit. So, <code>main.c</code> <code>#include</code>s <code>toc.c</code>, which <code>#include</code>s all of <code>toc</code>'s files. This improves (from scratch) compilation speeds, since you don't have to include headers a bunch of times for each translation unit. This is more of a problem in C++, where, for example, doing <code>#include &lt;map&gt;</code> ends up turning into 25,000 lines after preprocessing. All of toc's source code, which includes most of the C standard library, at the time of this writing (Dec 2019) is only 22,000 lines after preprocessing; imagine including all of that once for each translation unit which includes <code>map</code>. It also obviates the need for fancy build systems like CMake.</p>
+
+<h4>New features</h4>
+
+<p>Here are all the C99 features which <code>toc</code> depends on (I might have forgotten some...):</p>
+
+<ul>
+<li>Declare anywhere</li>
+<li><code>stdint.h</code></li>
+<li>Non-constant struct literal initializers (e.g. <code>int x[2] = {y, z};</code>)</li>
+<li>Variadic macros and <code>__VA_ARGS__</code></li>
+<li>Flexible array members</li>
+</ul>
+
+<p>The last three of those could all be removed fairly easily.</p>
+
+<p>And here are all of its C11 features:</p>
+
+<ul>
+<li>Anonymous structures/unions</li>
+<li><code>max_align_t</code> and <code>alignof</code> - It can still compile without these but it won't technically be standard-compliant</li>
+</ul>
+
+<h4>More</h4>
+
+<p>See <code>main.c</code> for a bit more information.</p>
+
+<hr />
+
+<p>* for those curious, it has to do with <code>goto</code>. In C, this program:</p>
+
+<pre><code>
+int main() {  
+    goto label;  
+    int x = 5;  
+    label:  
+    return 0;  
+}
+</code></pre>
+
+<p>Is completely fine. <code>x</code> will hold an unspecified value after the jump (but it isn't used so it doesn't really matter). Apparently, in C++, this is an ill-formed program. This is a bit ridiculous since</p>
+
+<pre><code>
+int main() {  
+    goto label;  
+    int x; x = 5;  
+    label:  
+    return 0;  
+}
+</code></pre>
+
+<p>is fine. So that's an interesting little "fun fact": <code>int x = 5;</code> isn't always the same as <code>int x; x = 5;</code> in C++.</p>
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