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authorChris Lattner <sabre@nondot.org>2007-11-05 20:13:56 +0000
committerChris Lattner <sabre@nondot.org>2007-11-05 20:13:56 +0000
commit619bc0ac1729090fa419606cb1ef5c5df9b58569 (patch)
treeac2e71076ace2612f90e66b320c0424451b3d191 /docs
parent0e555b1ab0be09b0c668f2af9fb7d5fe316897b5 (diff)
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merge in various fixes from Kelly Wilson.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43731 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
-rw-r--r--docs/tutorial/LangImpl1.html46
1 files changed, 24 insertions, 22 deletions
diff --git a/docs/tutorial/LangImpl1.html b/docs/tutorial/LangImpl1.html
index a0c9b16184..f57848b8e3 100644
--- a/docs/tutorial/LangImpl1.html
+++ b/docs/tutorial/LangImpl1.html
@@ -36,9 +36,10 @@
<div class="doc_text">
<p>Welcome to the "Implementing a language with LLVM" tutorial. This tutorial
-will run through implementation of a simple language, showing how fun and easy
-it can be. This tutorial will get you up and started and build a framework you
-can extend to other languages and to play with other things.
+will run the through implementation of a simple language, showing how fun and
+easy it can be. This tutorial will get you up and started as well as help to
+build a framework you can extend to other languages. You can also use this
+tutorial to help you start playing with other LLVM specific things.
</p>
</div>
@@ -53,16 +54,15 @@ can extend to other languages and to play with other things.
"<a href="http://en.wikipedia.org/wiki/Kaleidoscope">Kaleidoscope</a>".
Kaleidoscope is a procedural language that allows you to define functions, use
conditionals, math, etc. Over the course of the tutorial, we'll extend
-Kaleidoscope to support if/then/else, operator overloading, JIT compilation with
-a simple command line interface, etc.</p>
+Kaleidoscope to support the if/then/else construct, a for loop, user defined
+operators, JIT compilation with a simple command line interface, etc.</p>
-<p>Because we want to keep things simple, in Kaleidoscope the only datatype is a
+<p>Because we want to keep things simple, the only datatype in Kaleidoscope is a
64-bit floating point type (aka 'double' in C parlance). As such, all values
are implicitly double precision and the language doesn't require type
declarations. This gives the language a very nice and simple syntax. For
-example, A simple example computes <a
-href="http://en.wikipedia.org/wiki/Fibonacci_number">Fibonacci numbers</a>,
-which looks like this:</p>
+example, the following simple example computes <a
+href="http://en.wikipedia.org/wiki/Fibonacci_number">Fibonacci numbers:</a></p>
<div class="doc_code">
<pre>
@@ -96,8 +96,8 @@ atan2(sin(.4), cos(42))
<p>In the first incarnation of the language, we will only support basic
arithmetic: if/then/else will be added in a future installment. Another
interesting aspect of the first implementation is that it is a completely
-functional language, which does not allow you to have side-effects etc. We will
-eventually add side effects for those who prefer them.</p>
+functional language, which does not allow you to have side-effects, etc. We
+will eventually add side effects for those who prefer them.</p>
<p>In order to make this tutorial
maximally understandable and hackable, we choose to implement everything in C++
@@ -145,7 +145,7 @@ static double NumVal; // Filled in if tok_number
</div>
<p>Each token returned by our lexer will either be one of the Token enum values
-or it will be an 'unknown' character like '+' which is returned as its ascii
+or it will be an 'unknown' character like '+', which is returned as its ascii
value. If the current token is an identifier, the <tt>IdentifierStr</tt>
global variable holds the name of the identifier. If the current token is a
numeric literal (like 1.0), <tt>NumVal</tt> holds its value. Note that we use
@@ -153,9 +153,9 @@ global variables for simplicity, this is not the best choice for a real language
implementation :).
</p>
-<p>The actual implementation of the lexer is a single function <tt>gettok</tt>.
-<tt>gettok</tt> is called to return the next token from standard input. Its
-definition starts as:</p>
+<p>The actual implementation of the lexer is a single function named
+<tt>gettok</tt>. The <tt>gettok</tt> function is called to return the next token
+from standard input. Its definition starts as:</p>
<div class="doc_code">
<pre>
@@ -172,12 +172,12 @@ static int gettok() {
<p>
<tt>gettok</tt> works by calling the C <tt>getchar()</tt> function to read
characters one at a time from standard input. It eats them as it recognizes
-them and stores the last character read but not processed in LastChar. The
+them and stores the last character read, but not processed, in LastChar. The
first thing that it has to do is ignore whitespace between tokens. This is
accomplished with the loop above.</p>
-<p>The next thing it needs to do is recognize identifiers, and specific keywords
-like "def". Kaleidoscope does this with this simple loop:</p>
+<p>The next thing <tt>gettok</tt> needs to do is recognize identifiers and
+specific keywords like "def". Kaleidoscope does this with this simple loop:</p>
<div class="doc_code">
<pre>
@@ -193,9 +193,9 @@ like "def". Kaleidoscope does this with this simple loop:</p>
</pre>
</div>
-<p>Note that it sets the '<tt>IdentifierStr</tt>' global whenever it lexes an
-identifier. Also, since language keywords are matched by the same loop, we
-handle them here inline. Numeric values are similar:</p>
+<p>Note that this code sets the '<tt>IdentifierStr</tt>' global whenever it
+lexes an identifier. Also, since language keywords are matched by the same
+loop, we handle them here inline. Numeric values are similar:</p>
<div class="doc_code">
<pre>
@@ -251,7 +251,9 @@ this code:</p>
</pre>
</div>
-<p>With this, we have the complete lexer for the basic Kaleidoscope language.
+<p>With this, we have the complete lexer for the basic Kaleidoscope language
+(the <a href="LangImpl2.html#code">full code listing</a> for the Lexer is
+available in the <a href="LangImpl2.html">next chapter</a> of the tutorial).
Next we'll <a href="LangImpl2.html">build a simple parser that uses this to
build an Abstract Syntax Tree</a>. When we have that, we'll include a driver
so that you can use the lexer and parser together.