Imported Upstream version 60upstream/60

author: Ondřej Surý <ondrej@sury.org> 2011-09-13 13:13:40 +0200
committer: Ondřej Surý <ondrej@sury.org> 2011-09-13 13:13:40 +0200
commit: 5ff4c17907d5b19510a62e08fd8d3b11e62b431d (patch)
tree: c0650497e988f47be9c6f2324fa692a52dea82e1 /doc/talks/go_talk-20100112.html
parent: 80f18fc933cf3f3e829c5455a1023d69f7b86e52 (diff)
download: golang-upstream/60.tar.gz
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+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+<title>Go (January 12, 2010)</title>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<meta name="font-size-adjustment" content="-1" />
+<link rel="stylesheet" href="slidy.css"
+  type="text/css" media="screen, projection, print" />
+<script src="slidy.js" type="text/javascript">
+</script>
+</head>
+<body>
+<!-- this defines the slide background -->
+
+<div class="background">
+
+  <div class="header">
+  <!-- sized and colored via CSS -->
+  </div>
+
+  <div class="footer"></div>
+  </div>
+
+<div class="slide titlepage">
+<div style="height: 135px; width: 480px; overflow: hidden; position: fixed; top: auto; bottom: 10px; left: auto; right: 0;  ">
+<img src="../gordon/bumper480x270.png" style="margin: -135px 0 0 0;"/>
+</div>
+<!-- <img src="google.png" style="position: fixed; top: auto; bottom: 30px; left: 20px; right: auto;"/> -->
+<br/>
+<img src="../go-logo-white.png">
+<br/>
+<br/>
+<h1 style="padding-right: 0pt; margin-right: 0pt; color: #0066cc; font-size: 250%; border-bottom: 0px;">The Go Programming Language</h1>
+<div style="color: #ffcc00;">
+<h2>Russ Cox</h2>
+<!-- <h3><i>rsc@google.com</i></h3> -->
+<br/>
+<h3>Stanford University<br/><br/>January 12, 2010</h3>
+</div>
+</div>
+
+<div class="slide">
+	<h1>Go</h1>
+
+	<h2>New</h2>
+	<h2>Experimental</h2>
+	<h2>Concurrent</h2>
+	<h2>Garbage-collected</h2>
+	<h2>Systems</h2>
+	<h2>Language</h2>
+</div>
+
+<div class="slide">
+	<h1>Hello, world</h1>
+<pre>
+package main
+
+import "fmt"
+
+func main() {
+	fmt.Printf("Hello, 世界\n")
+}
+</pre>
+</div>
+
+<div class="slide">
+	<h1>History</h1>
+	
+	<h2>Design started in late 2007.</h2>
+	<h2>Implementation starting to work mid-2008.</h2>
+	<h2>Released as an open source project in November 2009.</h2>
+	<h2>Work continues.<h2>
+	<h2>Robert&nbsp;Griesemer, Ken&nbsp;Thompson, Rob&nbsp;Pike, Ian&nbsp;Lance&nbsp;Taylor, Russ&nbsp;Cox, many others</h2>
+</div>
+
+<div class="slide">
+	<h1>Why?</h1>
+	
+	<h2>Go fast!</h2>
+	<h2>Make programming fun again.</h2>
+</div>
+
+<div class="slide">
+	<h1>Why isn't programming fun?</h1>
+	
+	<div class="incremental">
+	<h2>Compiled, statically-typed languages (C, C++, Java) require too much typing and too much typing:</h2>
+	
+	<ul>
+		<li>verbose, lots of repetition</li>
+		<li>too much focus on type hierarchy</li>
+		<li>types get in the way as much as they help</li>
+		<li>compiles take far too long</li>
+	</ul>
+	</div>
+	
+	<div class="incremental">
+	<h2>Dynamic languages (Python, JavaScript) fix these problems (no more types, no more compiler) but introduce others:</h2>
+	
+	<ul>
+		<li>errors at run time that should be caught statically</li>
+		<li>no compilation means slow code</li>
+	</ul>
+	</div>
+	
+	<h2 class="incremental">Can we combine the best of both?</h2>
+</div>
+
+<div class="slide">
+	<h1>Go</h1>
+	
+	<h2>Make the language fast.</h2>
+	<h2>Make the tools fast.</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Static Types</h1>
+	
+	<h2>Static types, but declarations can infer type from expression:</h2>
+	
+<pre>
+var one, hi = 1, "hello"
+
+var double = func(x int) int { return x*2 }
+</pre>
+
+	<h2>Not full Hindley-Milner type inference.</h2>
+</div>
+
+
+<div class="slide">
+	<h1>Go Approach: Methods</h1>
+	
+	<h2>Methods can be defined on any type.</h2>
+
+<pre>
+type Point struct {
+	X, Y float64
+}
+
+func (p Point) Abs() float64 {
+	return math.Sqrt(p.X*p.X + p.Y*p.Y)
+}
+</pre>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Methods</h1>
+	
+	<h2>Methods can be defined on any type.</h2>
+
+<pre>
+type MyFloat float64
+
+func (f MyFloat) Abs() float64 {
+	v := float64(f)
+	if v < 0 {
+		v = -v
+	}
+	return v
+}
+</pre>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Abstract Types</h1>
+	
+	<h2>An interface type lists a set of methods. Any value with those methods satisfies the interface.</h2>
+
+<pre>
+type Abser interface {
+	Abs() float64
+}
+
+func AbsPrinter(a Abser)
+</pre>
+
+	<h2>Can use Point or MyFloat (or ...):</h2>
+
+<pre>
+p := Point{3, 4}
+AbsPrinter(p)
+
+f := MyFloat(-10)
+AbsPrinter(f)
+</pre>
+
+	<h2>Notice that Point never declared that it implements Abser. It just does.  Same with MyFloat.</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Packages</h1>
+
+	<h2>A Go program comprises one or more packages.</h2>
+	<h2>Each package is one or more source files compiled and imported as a unit.</h2>
+<pre>
+package draw
+
+type Point struct {
+	X, Y int
+}
+</pre>
+
+<pre>
+package main
+
+import "draw"
+
+var p draw.Point
+</pre>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Visibility</h1>
+	
+	<h2>Inside a package, all locally defined names are visible in all source files.</h2>
+	
+	<h2>When imported, only the upper case names are visible.</h2>
+
+<pre>
+package draw
+
+type <span style="color: black;">Point</span> struct {
+	<span style="color: black;">X</span>, <span style="color: black;">Y</span> int
+	dist float64
+}
+
+type cache map[Point] float64
+</pre>
+
+<h2>Clients that <code>import "draw"</code> can use the black names only.</h2>
+
+<h2>&ldquo;Shift is the new <code>public</code>.&rdquo;</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Concurrency</h1>
+	
+	<h2>Cheap to create a new flow of control (goroutine):</h2>
+	
+<pre>
+func main() {
+	go expensiveComputation(x, y, z)
+	anotherExpensiveComputation(a, b, c)
+}
+</pre>
+
+	<h2>Two expensive computations in parallel.</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Approach: Synchronization</h1>
+	
+	<h2>Use explicit messages to communicate and synchronize.</h2>
+	
+<pre>
+func computeAndSend(ch chan int, x, y, z int) {
+	ch <- expensiveComputation(x, y, z)
+}
+
+func main() {
+	ch := make(chan int)
+	go computeAndSend(ch, x, y, z)
+	v2 := anotherExpensiveComputation(a, b, c)
+	v1 := <-ch
+	fmt.Println(v1, v2)
+}
+</pre>
+	<h2>Notice communication of result in addition to synchronization.</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Fast: Language</h1>
+	
+	<h2 class="incremental">Static types: enough to compile well, but inferred much of the time.</h2>
+	
+	<h2 class="incremental">Methods: on any type, orthogonal to type system.</h2>
+	
+	<h2 class="incremental">Abstract types: interface values, relations inferred statically.</h2>
+	
+	<h2 class="incremental">Visibility: inferred from case of name.</h2>
+	
+	<h2 class="incremental">Concurrency: lightweight way to start new thread of control.</h2>
+	
+	<h2 class="incremental">Synchronization: explicit, easy message passing.</h2>
+
+	<br/>
+	
+	<h2 class="incremental">Lightweight feel of a scripting language but compiled.</h2>
+</div>
+
+<div class="slide">
+	<h1>Compile fast</h1>
+
+	<div class="incremental">
+	<h2>Observation: much of the compile time for a source file is spent processing
+	other, often unrelated files.</h2>
+
+	<h2>In C: <code>a.c</code> includes <code>b.h</code>, which includes <code>c.h</code>, which includes <code>d.h</code>.
+	</h2>
+	
+	<h2>Except that it's more often a tree instead of a chain.</h2>
+	
+	<h2>On my Mac (OS X 10.5.8, gcc 4.0.1):</h2>
+	<ul>
+	<li>C: <code>#include &lt;stdio.h&gt;</code> reads 360 lines from 9 files.
+	<li>C++: <code>#include &lt;iostream&gt;</code> reads 25,326 lines from 131 files.
+	<li>Objective C: <code>#include &lt;Carbon/Carbon.h&gt;</code> reads 124,730 lines from 689 files.
+	</ul>
+	
+	<h2>And we haven't done any real work yet!</h2>
+	
+	<h2>Same story in Java, Python, but reading binaries instead of source files.</h2>
+	</div>
+</div>
+
+<div class="slide">
+	<h1>Implementation: Summarize Dependencies</h1>
+	
+<pre>
+package gui
+
+import "draw"
+
+type Mouse struct {
+	Loc draw.Point
+	Buttons uint
+}
+</pre>
+	<h2>Compiled form of <code>gui</code> summarizes the necessary part of <code>draw</code> (just <code>Point</code>).</h2>
+
+</div>
+
+<div class="slide">
+	<h1>Implementation: Summarize Dependencies</h1>
+
+	<h2>Compiled form of <code>gui</code> summarizes the necessary part of <code>draw</code> (just <code>Point</code>).  Pseudo-object:</h2>
+
+<pre>
+package gui
+type draw.Point struct {
+	X, Y int
+}
+type gui.Mouse struct {
+	Loc draw.Point
+	Buttons uint
+}
+</pre>
+
+	<h2>A file that imports <code>gui</code> compiles without consulting <code>draw</code> or its dependencies.</h2>
+	
+	<h2>In Go: <code>import "fmt"</code> reads <i>one</i> file: 184 lines summarizing types from 7 packages.</h2>
+
+	<h2>Tiny effect in this program but can be exponential in large programs.</h2>
+</div>
+
+<div class="slide">
+	<h1>Compilation Demo</h1>
+	
+	<h2>Build all standard Go packages: ~120,000 lines of code.</h2>
+</div>
+
+<div class="slide">
+	<h1>Go Status</h1>
+	
+	<div class="incremental">
+	<div>
+	<h2>Open source:</h2>
+	<ul>
+	<li>released on November 10, 2009
+	<li>regular releases (~ weekly)
+	<li>all development done in public Mercurial repository
+	<li>outside contributions welcome
+	</ul>
+	</div>
+	
+	<div>
+	<h2>Portable:</h2>
+	<ul>
+	<li>FreeBSD, Linux, OS X (x86, x86-64)
+	<li>(in progress) Linux arm, Native Client x86, Windows x86.
+	</ul>
+	</div>
+	
+	<div>
+	<h2>Still in progress, experimental.  Yet to come:</h2>
+	<ul>
+	<li>mature garbage collector
+	<li>generics?
+	<li>exceptions?
+	<li>unions or sum types?
+	</ul>
+	</div>
+	</div>
+
+</div>
+
+<div class="slide titlepage">
+	<h1>Questions?</h1>
+	<br><br>
+	<center>
+	<img src="../gordon/bumper640x360.png">
+	</center>
+	<br><br>
+	<div style="color: #ffcc00;">
+	<!-- <h3><i>rsc@google.com</i></h3> -->
+	</div>
+</div>
+
+</body></html>
author	Ondřej Surý <ondrej@sury.org>	2011-09-13 13:13:40 +0200
committer	Ondřej Surý <ondrej@sury.org>	2011-09-13 13:13:40 +0200
commit	5ff4c17907d5b19510a62e08fd8d3b11e62b431d (patch)
tree	c0650497e988f47be9c6f2324fa692a52dea82e1 /doc/talks/go_talk-20100112.html
parent	80f18fc933cf3f3e829c5455a1023d69f7b86e52 (diff)
download	golang-upstream/60.tar.gz