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tutorial: remove all line numbers and references to them.
R=golang-dev, mikioh.mikioh, dsymonds CC=golang-dev https://golang.org/cl/4675070
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@ -19,9 +19,6 @@ The presentation here proceeds through a series of modest programs to illustrate
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key features of the language. All the programs work (at time of writing) and are
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key features of the language. All the programs work (at time of writing) and are
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checked into the repository in the directory <a href='/doc/progs'><code>/doc/progs/</code></a>.
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checked into the repository in the directory <a href='/doc/progs'><code>/doc/progs/</code></a>.
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<p>
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<p>
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Program snippets are annotated with the line number in the original file; for
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cleanliness, blank lines remain blank.
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<p>
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<h2>Hello, World</h2>
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<h2>Hello, World</h2>
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<p>
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<p>
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Let's start in the usual way:
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Let's start in the usual way:
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@ -176,12 +173,13 @@ a naming conflict.
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<p>
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<p>
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Given <code>os.Stdout</code> we can use its <code>WriteString</code> method to print the string.
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Given <code>os.Stdout</code> we can use its <code>WriteString</code> method to print the string.
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<p>
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<p>
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Having imported the <code>flag</code> package, line 12 creates a global variable to hold
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After importing the <code>flag</code> package, we use a <code>var</code> declaration
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the value of echo's <code>-n</code> flag. The variable <code>omitNewline</code> has type <code>*bool</code>, pointer
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to create and initialize a global variable, called <code>omitNewline</code>,
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to <code>bool</code>.
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to hold the value of echo's <code>-n</code> flag.
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The variable has type <code>*bool</code>, pointer to <code>bool</code>.
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<p>
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<p>
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In <code>main.main</code>, we parse the arguments (line 20) and then create a local
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In <code>main.main</code>, we parse the arguments (the call to <code>flag.Parse</code>) and then create a local
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string variable we will use to build the output.
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string variable with which to build the output.
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<p>
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<p>
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The declaration statement has the form
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The declaration statement has the form
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<p>
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<p>
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@ -261,7 +259,9 @@ reassigning it. This snippet from <code>strings.go</code> is legal code:
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<p>
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<p>
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<pre><!-- progs/strings.go /hello/ /ciao/
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<pre><!-- progs/strings.go /hello/ /ciao/
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--> s := "hello"
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--> s := "hello"
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if s[1] != 'e' { os.Exit(1) }
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if s[1] != 'e' {
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os.Exit(1)
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}
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s = "good bye"
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s = "good bye"
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var p *string = &s
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var p *string = &s
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*p = "ciao"
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*p = "ciao"
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@ -540,7 +540,7 @@ return n
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</pre>
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</pre>
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<p>
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<p>
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but for simple structures like <code>File</code> it's easier to return the address of a
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but for simple structures like <code>File</code> it's easier to return the address of a
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composite literal, as is done here on line 21.
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composite literal, as is done here in the <code>return</code> statement from <code>newFile</code>.
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<p>
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<p>
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We can use the factory to construct some familiar, exported variables of type <code>*File</code>:
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We can use the factory to construct some familiar, exported variables of type <code>*File</code>:
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<p>
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<p>
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@ -573,9 +573,9 @@ multi-value return as a parenthesized list of declarations; syntactically
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they look just like a second parameter list. The function
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they look just like a second parameter list. The function
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<code>syscall.Open</code>
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<code>syscall.Open</code>
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also has a multi-value return, which we can grab with the multi-variable
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also has a multi-value return, which we can grab with the multi-variable
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declaration on line 31; it declares <code>r</code> and <code>e</code> to hold the two values,
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declaration on the first line; it declares <code>r</code> and <code>e</code> to hold the two values,
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both of type <code>int</code> (although you'd have to look at the <code>syscall</code> package
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both of type <code>int</code> (although you'd have to look at the <code>syscall</code> package
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to see that). Finally, line 35 returns two values: a pointer to the new <code>File</code>
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to see that). Finally, <code>OpenFile</code> returns two values: a pointer to the new <code>File</code>
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and the error. If <code>syscall.Open</code> fails, the file descriptor <code>r</code> will
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and the error. If <code>syscall.Open</code> fails, the file descriptor <code>r</code> will
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be negative and <code>newFile</code> will return <code>nil</code>.
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be negative and <code>newFile</code> will return <code>nil</code>.
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<p>
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<p>
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@ -20,9 +20,6 @@ The presentation here proceeds through a series of modest programs to illustrate
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key features of the language. All the programs work (at time of writing) and are
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key features of the language. All the programs work (at time of writing) and are
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checked into the repository in the directory <a href='/doc/progs'>"/doc/progs/"</a>.
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checked into the repository in the directory <a href='/doc/progs'>"/doc/progs/"</a>.
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Program snippets are annotated with the line number in the original file; for
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cleanliness, blank lines remain blank.
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Hello, World
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Hello, World
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----
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----
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@ -136,12 +133,13 @@ a naming conflict.
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Given "os.Stdout" we can use its "WriteString" method to print the string.
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Given "os.Stdout" we can use its "WriteString" method to print the string.
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Having imported the "flag" package, line 12 creates a global variable to hold
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After importing the "flag" package, we use a "var" declaration
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the value of echo's "-n" flag. The variable "omitNewline" has type "*bool", pointer
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to create and initialize a global variable, called "omitNewline",
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to "bool".
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to hold the value of echo's "-n" flag.
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The variable has type "*bool", pointer to "bool".
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In "main.main", we parse the arguments (line 20) and then create a local
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In "main.main", we parse the arguments (the call to "flag.Parse") and then create a local
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string variable we will use to build the output.
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string variable with which to build the output.
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The declaration statement has the form
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The declaration statement has the form
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@ -429,7 +427,7 @@ object. We could write
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return n
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return n
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but for simple structures like "File" it's easier to return the address of a
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but for simple structures like "File" it's easier to return the address of a
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composite literal, as is done here on line 21.
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composite literal, as is done here in the "return" statement from "newFile".
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We can use the factory to construct some familiar, exported variables of type "*File":
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We can use the factory to construct some familiar, exported variables of type "*File":
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@ -447,9 +445,9 @@ multi-value return as a parenthesized list of declarations; syntactically
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they look just like a second parameter list. The function
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they look just like a second parameter list. The function
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"syscall.Open"
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"syscall.Open"
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also has a multi-value return, which we can grab with the multi-variable
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also has a multi-value return, which we can grab with the multi-variable
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declaration on line 31; it declares "r" and "e" to hold the two values,
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declaration on the first line; it declares "r" and "e" to hold the two values,
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both of type "int" (although you'd have to look at the "syscall" package
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both of type "int" (although you'd have to look at the "syscall" package
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to see that). Finally, line 35 returns two values: a pointer to the new "File"
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to see that). Finally, "OpenFile" returns two values: a pointer to the new "File"
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and the error. If "syscall.Open" fails, the file descriptor "r" will
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and the error. If "syscall.Open" fails, the file descriptor "r" will
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be negative and "newFile" will return "nil".
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be negative and "newFile" will return "nil".
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