mirror of
https://github.com/golang/go
synced 2024-11-05 18:36:08 +00:00
411 lines
9.1 KiB
HTML
411 lines
9.1 KiB
HTML
<!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 Griesemer, Ken Thompson, Rob Pike, Ian Lance Taylor, Russ 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>“Shift is the new <code>public</code>.”</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 <stdio.h></code> reads 360 lines from 9 files.
|
|
<li>C++: <code>#include <iostream></code> reads 25,326 lines from 131 files.
|
|
<li>Objective C: <code>#include <Carbon/Carbon.h></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>
|