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Diffstat (limited to 'doc/code.html')
| -rw-r--r-- | doc/code.html | 183 |
1 files changed, 96 insertions, 87 deletions
diff --git a/doc/code.html b/doc/code.html index f019306fa..ce9f8636f 100644 --- a/doc/code.html +++ b/doc/code.html @@ -60,37 +60,35 @@ To give you an idea of how a workspace looks in practice, here's an example: <pre> bin/ - streak # command executable - todo # command executable + hello # command executable + outyet # command executable pkg/ linux_amd64/ - code.google.com/p/goauth2/ - oauth.a # package object - github.com/nf/todo/ - task.a # package object + github.com/golang/example/ + stringutil.a # package object src/ - code.google.com/p/goauth2/ - .hg/ # mercurial repository metadata - oauth/ - oauth.go # package source - oauth_test.go # test source - github.com/nf/ - streak/ - .git/ # git repository metadata - oauth.go # command source - streak.go # command source - todo/ - .git/ # git repository metadata - task/ - task.go # package source - todo.go # command source + <a href="https://github.com/golang/example/">github.com/golang/example/</a> + .git/ # Git repository metadata + hello/ + hello.go # command source + outyet/ + main.go # command source + main_test.go # test source + stringutil/ + reverse.go # package source + reverse_test.go # test source </pre> <p> -This workspace contains three repositories (<code>goauth2</code>, -<code>streak</code>, and <code>todo</code>) comprising two commands -(<code>streak</code> and <code>todo</code>) and two libraries -(<code>oauth</code> and <code>task</code>). +This workspace contains one repository (<code>example</code>) +comprising two commands (<code>hello</code> and <code>outyet</code>) +and one library (<code>stringutil</code>). +</p> + +<p> +A typical workspace would contain many source repositories containing many +packages and commands. Most Go programmers keep <i>all</i> their Go source code +and dependencies in a single workspace. </p> <p> @@ -277,29 +275,29 @@ Let's write a library and use it from the <code>hello</code> program. <p> Again, the first step is to choose a package path (we'll use -<code>github.com/user/newmath</code>) and create the package directory: +<code>github.com/user/stringutil</code>) and create the package directory: </p> <pre> -$ <b>mkdir $GOPATH/src/github.com/user/newmath</b> +$ <b>mkdir $GOPATH/src/github.com/user/stringutil</b> </pre> <p> -Next, create a file named <code>sqrt.go</code> in that directory with the +Next, create a file named <code>reverse.go</code> in that directory with the following contents. </p> <pre> -// Package newmath is a trivial example package. -package newmath - -// Sqrt returns an approximation to the square root of x. -func Sqrt(x float64) float64 { - z := 1.0 - for i := 0; i < 1000; i++ { - z -= (z*z - x) / (2 * z) +// Package stringutil contains utility functions for working with strings. +package stringutil + +// Reverse returns its argument string reversed rune-wise left to right. +func Reverse(s string) string { + r := []rune(s) + for i, j := 0, len(r)-1; i < len(r)/2; i, j = i+1, j-1 { + r[i], r[j] = r[j], r[i] } - return z + return string(r) } </pre> @@ -308,7 +306,7 @@ Now, test that the package compiles with <code>go build</code>: </p> <pre> -$ <b>go build github.com/user/newmath</b> +$ <b>go build github.com/user/stringutil</b> </pre> <p> @@ -326,7 +324,7 @@ directory of the workspace. </p> <p> -After confirming that the <code>newmath</code> package builds, +After confirming that the <code>stringutil</code> package builds, modify your original <code>hello.go</code> (which is in <code>$GOPATH/src/github.com/user/hello</code>) to use it: </p> @@ -337,18 +335,18 @@ package main import ( "fmt" - <b>"github.com/user/newmath"</b> + <b>"github.com/user/stringutil"</b> ) func main() { - fmt.Printf("Hello, world. <b>Sqrt(2) = %v\n", newmath.Sqrt(2)</b>) + fmt.Printf(stringutil.Reverse("!oG ,olleH")) } </pre> <p> Whenever the <code>go</code> tool installs a package or binary, it also -installs whatever dependencies it has. So when you install the <code>hello</code> -program +installs whatever dependencies it has. +So when you install the <code>hello</code> program </p> <pre> @@ -356,16 +354,16 @@ $ <b>go install github.com/user/hello</b> </pre> <p> -the <code>newmath</code> package will be installed as well, automatically. +the <code>stringutil</code> package will be installed as well, automatically. </p> <p> -Running the new version of the program, you should see some numerical output: +Running the new version of the program, you should see a new, reversed message: </p> <pre> $ <b>hello</b> -Hello, world. Sqrt(2) = 1.414213562373095 +Hello, Go! </pre> <p> @@ -374,22 +372,22 @@ After the steps above, your workspace should look like this: <pre> bin/ - hello # command executable + hello # command executable pkg/ - linux_amd64/ # this will reflect your OS and architecture + linux_amd64/ # this will reflect your OS and architecture github.com/user/ - newmath.a # package object + stringutil.a # package object src/ github.com/user/ hello/ - hello.go # command source - newmath/ - sqrt.go # package source + hello.go # command source + stringutil/ + reverse.go # package source </pre> <p> -Note that <code>go install</code> placed the <code>newmath.a</code> object in a -directory inside <code>pkg/linux_amd64</code> that mirrors its source +Note that <code>go install</code> placed the <code>stringutil.a</code> object +in a directory inside <code>pkg/linux_amd64</code> that mirrors its source directory. This is so that future invocations of the <code>go</code> tool can find the package object and avoid recompiling the package unnecessarily. @@ -457,20 +455,29 @@ if the function calls a failure function such as <code>t.Error</code> or </p> <p> -Add a test to the <code>newmath</code> package by creating the file -<code>$GOPATH/src/github.com/user/newmath/sqrt_test.go</code> containing the -following Go code. +Add a test to the <code>stringutil</code> package by creating the file +<code>$GOPATH/src/github.com/user/stringutil/reverse_test.go</code> containing +the following Go code. </p> <pre> -package newmath +package stringutil import "testing" -func TestSqrt(t *testing.T) { - const in, out = 4, 2 - if x := Sqrt(in); x != out { - t.Errorf("Sqrt(%v) = %v, want %v", in, x, out) +func TestReverse(t *testing.T) { + cases := []struct { + in, want string + }{ + {"Hello, world", "dlrow ,olleH"}, + {"Hello, 世界", "界世 ,olleH"}, + {"", ""}, + } + for _, c := range cases { + got := Reverse(c.in) + if got != c.want { + t.Errorf("Reverse(%q) == %q, want %q", c.in, got, c.want) + } } } </pre> @@ -480,8 +487,8 @@ Then run the test with <code>go test</code>: </p> <pre> -$ <b>go test github.com/user/newmath</b> -ok github.com/user/newmath 0.165s +$ <b>go test github.com/user/stringutil</b> +ok github.com/user/stringutil 0.165s </pre> <p> @@ -491,7 +498,7 @@ directory, you can omit the package path: <pre> $ <b>go test</b> -ok github.com/user/newmath 0.165s +ok github.com/user/stringutil 0.165s </pre> <p> @@ -507,16 +514,16 @@ An import path can describe how to obtain the package source code using a revision control system such as Git or Mercurial. The <code>go</code> tool uses this property to automatically fetch packages from remote repositories. For instance, the examples described in this document are also kept in a -Mercurial repository hosted at Google Code, -<code><a href="//code.google.com/p/go.example">code.google.com/p/go.example</a></code>. +Git repository hosted at GitHub +<code><a href="https://github.com/golang/example">github.com/golang/example</a></code>. If you include the repository URL in the package's import path, <code>go get</code> will fetch, build, and install it automatically: </p> <pre> -$ <b>go get code.google.com/p/go.example/hello</b> +$ <b>go get github.com/golang/example/hello</b> $ <b>$GOPATH/bin/hello</b> -Hello, world. Sqrt(2) = 1.414213562373095 +Hello, Go examples! </pre> <p> @@ -533,37 +540,39 @@ tree should now look like this: <pre> bin/ - hello # command executable + hello # command executable pkg/ linux_amd64/ - code.google.com/p/go.example/ - newmath.a # package object + github.com/golang/example/ + stringutil.a # package object github.com/user/ - newmath.a # package object + stringutil.a # package object src/ - code.google.com/p/go.example/ + github.com/golang/example/ + .git/ # Git repository metadata hello/ - hello.go # command source - newmath/ - sqrt.go # package source - sqrt_test.go # test source + hello.go # command source + stringutil/ + reverse.go # package source + reverse_test.go # test source github.com/user/ hello/ - hello.go # command source - newmath/ - sqrt.go # package source - sqrt_test.go # test source + hello.go # command source + stringutil/ + reverse.go # package source + reverse_test.go # test source </pre> <p> -The <code>hello</code> command hosted at Google Code depends on the -<code>newmath</code> package within the same repository. The imports in -<code>hello.go</code> file use the same import path convention, so the <code>go -get</code> command is able to locate and install the dependent package, too. +The <code>hello</code> command hosted at GitHub depends on the +<code>stringutil</code> package within the same repository. The imports in +<code>hello.go</code> file use the same import path convention, so the +<code>go get</code> command is able to locate and install the dependent +package, too. </p> <pre> -import "code.google.com/p/go.example/newmath" +import "github.com/golang/example/stringutil" </pre> <p> |