[ { "path": ".github/workflows/test.yaml", "content": "name: test\non: \n push:\n branches:\n - master\n pull_request:\n branches:\n - master\n\njobs:\n test:\n strategy:\n matrix:\n os: [ubuntu-latest]\n go-version: [1.17.x, 1.16.x]\n runs-on: ${{ matrix.os }}\n steps:\n - name: Install Go\n uses: actions/setup-go@v2\n with:\n go-version: ${{ matrix.go-version }}\n - name: Checkout code\n uses: actions/checkout@v2\n - name: Build\n run: go build ./...\n - name: Test\n run: go test -v ./...\n" }, { "path": ".gitignore", "content": "dist/\ntestpages/*\ntests/test_results.txt\nrobots.html\n" }, { "path": "LICENSE", "content": "Copyright (c) 2014: Eric Chiang\n\nPermission is hereby granted, free of charge, to any person obtaining a copy\nof this software and associated documentation files (the \"Software\"), to deal\nin the Software without restriction, including without limitation the rights\nto use, copy, modify, merge, publish, distribute, sublicense, and/or sell\ncopies of the Software, and to permit persons to whom the Software is\nfurnished to do so, subject to the following conditions:\n\nThe above copyright notice and this permission notice shall be included in\nall copies or substantial portions of the Software.\n\nTHE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR\nIMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,\nFITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE\nAUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER\nLIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,\nOUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN\nTHE SOFTWARE.\n" }, { "path": "README.md", "content": "# pup\n\npup is a command line tool for processing HTML. It reads from stdin,\nprints to stdout, and allows the user to filter parts of the page using\n[CSS selectors](https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_started/Selectors).\n\nInspired by [jq](http://stedolan.github.io/jq/), pup aims to be a\nfast and flexible way of exploring HTML from the terminal.\n\n## Install\n\nDirect downloads are available through the [releases page](https://github.com/EricChiang/pup/releases/latest).\n\nIf you have Go installed on your computer just run `go get`.\n\n go get github.com/ericchiang/pup\n\nIf you're on OS X, use [Homebrew](http://brew.sh/) to install (no Go required).\n\n brew install https://raw.githubusercontent.com/EricChiang/pup/master/pup.rb\n\n## Quick start\n\n```bash\n$ curl -s https://news.ycombinator.com/\n```\n\nEw, HTML. Let's run that through some pup selectors:\n\n```bash\n$ curl -s https://news.ycombinator.com/ | pup 'table table tr:nth-last-of-type(n+2) td.title a'\n```\n\nOkay, how about only the links?\n\n```bash\n$ curl -s https://news.ycombinator.com/ | pup 'table table tr:nth-last-of-type(n+2) td.title a attr{href}'\n```\n\nEven better, let's grab the titles too:\n\n```bash\n$ curl -s https://news.ycombinator.com/ | pup 'table table tr:nth-last-of-type(n+2) td.title a json{}'\n```\n\n## Basic Usage\n\n```bash\n$ cat index.html | pup [flags] '[selectors] [display function]'\n```\n\n## Examples\n\nDownload a webpage with wget.\n\n```bash\n$ wget http://en.wikipedia.org/wiki/Robots_exclusion_standard -O robots.html\n```\n\n#### Clean and indent\n\nBy default pup will fill in missing tags and properly indent the page.\n\n```bash\n$ cat robots.html\n# nasty looking HTML\n$ cat robots.html | pup --color\n# cleaned, indented, and colorful HTML\n```\n\n#### Filter by tag\n\n```bash\n$ cat robots.html | pup 'title'\n\n Robots exclusion standard - Wikipedia, the free encyclopedia\n\n```\n\n#### Filter by id\n\n```bash\n$ cat robots.html | pup 'span#See_also'\n\n See also\n\n```\n\n#### Filter by attribute\n\n```bash\n$ cat robots.html | pup 'th[scope=\"row\"]'\n\n Exclusion standards\n\n\n Related marketing topics\n\n\n Search marketing related topics\n\n\n Search engine spam\n\n\n Linking\n\n\n People\n\n\n Other\n\n```\n\n#### Pseudo Classes\n\nCSS selectors have a group of specifiers called [\"pseudo classes\"](\nhttps://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-classes) which are pretty\ncool. pup implements a majority of the relevant ones them.\n\nHere are some examples.\n\n```bash\n$ cat robots.html | pup 'a[rel]:empty'\n\n\n```\n\n```bash\n$ cat robots.html | pup ':contains(\"History\")'\n\n History\n\n\n History\n\n```\n\n```bash\n$ cat robots.html | pup ':parent-of([action=\"edit\"])'\n\n \n Edit links\n \n\n```\n\nFor a complete list, view the [implemented selectors](#implemented-selectors)\nsection.\n\n\n#### `+`, `>`, and `,`\n\nThese are intermediate characters that declare special instructions. For\ninstance, a comma `,` allows pup to specify multiple groups of selectors.\n\n```bash\n$ cat robots.html | pup 'title, h1 span[dir=\"auto\"]'\n\n Robots exclusion standard - Wikipedia, the free encyclopedia\n\n\n Robots exclusion standard\n\n```\n\n#### Chain selectors together\n\nWhen combining selectors, the HTML nodes selected by the previous selector will\nbe passed to the next ones.\n\n```bash\n$ cat robots.html | pup 'h1#firstHeading'\n

\n \n Robots exclusion standard\n \n

\n```\n\n```bash\n$ cat robots.html | pup 'h1#firstHeading span'\n\n Robots exclusion standard\n\n```\n\n## Implemented Selectors\n\nFor further examples of these selectors head over to [MDN](\nhttps://developer.mozilla.org/en-US/docs/Web/CSS/Reference).\n\n```bash\npup '.class'\npup '#id'\npup 'element'\npup 'selector + selector'\npup 'selector > selector'\npup '[attribute]'\npup '[attribute=\"value\"]'\npup '[attribute*=\"value\"]'\npup '[attribute~=\"value\"]'\npup '[attribute^=\"value\"]'\npup '[attribute$=\"value\"]'\npup ':empty'\npup ':first-child'\npup ':first-of-type'\npup ':last-child'\npup ':last-of-type'\npup ':only-child'\npup ':only-of-type'\npup ':contains(\"text\")'\npup ':nth-child(n)'\npup ':nth-of-type(n)'\npup ':nth-last-child(n)'\npup ':nth-last-of-type(n)'\npup ':not(selector)'\npup ':parent-of(selector)'\n```\n\nYou can mix and match selectors as you wish.\n\n```bash\ncat index.html | pup 'element#id[attribute=\"value\"]:first-of-type'\n```\n\n## Display Functions\n\nNon-HTML selectors which effect the output type are implemented as functions\nwhich can be provided as a final argument.\n\n#### `text{}`\n\nPrint all text from selected nodes and children in depth first order.\n\n```bash\n$ cat robots.html | pup '.mw-headline text{}'\nHistory\nAbout the standard\nDisadvantages\nAlternatives\nExamples\nNonstandard extensions\nCrawl-delay directive\nAllow directive\nSitemap\nHost\nUniversal \"*\" match\nMeta tags and headers\nSee also\nReferences\nExternal links\n```\n\n#### `attr{attrkey}`\n\nPrint the values of all attributes with a given key from all selected nodes.\n\n```bash\n$ cat robots.html | pup '.catlinks div attr{id}'\nmw-normal-catlinks\nmw-hidden-catlinks\n```\n\n#### `json{}`\n\nPrint HTML as JSON.\n\n```bash\n$ cat robots.html | pup 'div#p-namespaces a'\n\n Article\n\n\n Talk\n\n```\n\n```bash\n$ cat robots.html | pup 'div#p-namespaces a json{}'\n[\n {\n \"accesskey\": \"c\",\n \"href\": \"/wiki/Robots_exclusion_standard\",\n \"tag\": \"a\",\n \"text\": \"Article\",\n \"title\": \"View the content page [c]\"\n },\n {\n \"accesskey\": \"t\",\n \"href\": \"/wiki/Talk:Robots_exclusion_standard\",\n \"tag\": \"a\",\n \"text\": \"Talk\",\n \"title\": \"Discussion about the content page [t]\"\n }\n]\n```\n\nUse the `-i` / `--indent` flag to control the intent level.\n\n```bash\n$ cat robots.html | pup -i 4 'div#p-namespaces a json{}'\n[\n {\n \"accesskey\": \"c\",\n \"href\": \"/wiki/Robots_exclusion_standard\",\n \"tag\": \"a\",\n \"text\": \"Article\",\n \"title\": \"View the content page [c]\"\n },\n {\n \"accesskey\": \"t\",\n \"href\": \"/wiki/Talk:Robots_exclusion_standard\",\n \"tag\": \"a\",\n \"text\": \"Talk\",\n \"title\": \"Discussion about the content page [t]\"\n }\n]\n```\n\nIf the selectors only return one element the results will be printed as a JSON\nobject, not a list.\n\n```bash\n$ cat robots.html | pup --indent 4 'title json{}'\n{\n \"tag\": \"title\",\n \"text\": \"Robots exclusion standard - Wikipedia, the free encyclopedia\"\n}\n```\n\nBecause there is no universal standard for converting HTML/XML to JSON, a\nmethod has been chosen which hopefully fits. The goal is simply to get the\noutput of pup into a more consumable format.\n\n## Flags\n\nRun `pup --help` for a list of further options\n" }, { "path": "display.go", "content": "package main\n\nimport (\n\t\"encoding/json\"\n\t\"fmt\"\n\t\"regexp\"\n\t\"strings\"\n\n\t\"github.com/fatih/color\"\n\tcolorable \"github.com/mattn/go-colorable\"\n\t\"golang.org/x/net/html\"\n\t\"golang.org/x/net/html/atom\"\n)\n\nfunc init() {\n\tcolor.Output = colorable.NewColorableStdout()\n}\n\ntype Displayer interface {\n\tDisplay([]*html.Node)\n}\n\nfunc ParseDisplayer(cmd string) error {\n\tattrRe := regexp.MustCompile(`attr\\{([a-zA-Z\\-]+)\\}`)\n\tif cmd == \"text{}\" {\n\t\tpupDisplayer = TextDisplayer{}\n\t} else if cmd == \"json{}\" {\n\t\tpupDisplayer = JSONDisplayer{}\n\t} else if match := attrRe.FindAllStringSubmatch(cmd, -1); len(match) == 1 {\n\t\tpupDisplayer = AttrDisplayer{\n\t\t\tAttr: match[0][1],\n\t\t}\n\t} else {\n\t\treturn fmt.Errorf(\"Unknown displayer\")\n\t}\n\treturn nil\n}\n\n// Is this node a tag with no end tag such as or
?\n// http://www.w3.org/TR/html-markup/syntax.html#syntax-elements\nfunc isVoidElement(n *html.Node) bool {\n\tswitch n.DataAtom {\n\tcase atom.Area, atom.Base, atom.Br, atom.Col, atom.Command, atom.Embed,\n\t\tatom.Hr, atom.Img, atom.Input, atom.Keygen, atom.Link,\n\t\tatom.Meta, atom.Param, atom.Source, atom.Track, atom.Wbr:\n\t\treturn true\n\t}\n\treturn false\n}\n\nvar (\n\t// Colors\n\ttagColor *color.Color = color.New(color.FgCyan)\n\ttokenColor = color.New(color.FgCyan)\n\tattrKeyColor = color.New(color.FgMagenta)\n\tquoteColor = color.New(color.FgBlue)\n\tcommentColor = color.New(color.FgYellow)\n)\n\ntype TreeDisplayer struct {\n}\n\nfunc (t TreeDisplayer) Display(nodes []*html.Node) {\n\tfor _, node := range nodes {\n\t\tt.printNode(node, 0)\n\t}\n}\n\n// The 
 tag indicates that the text within it should always be formatted\n// as is. See https://github.com/ericchiang/pup/issues/33\nfunc (t TreeDisplayer) printPre(n *html.Node) {\n\tswitch n.Type {\n\tcase html.TextNode:\n\t\ts := n.Data\n\t\tif pupEscapeHTML {\n\t\t\t// don't escape javascript\n\t\t\tif n.Parent == nil || n.Parent.DataAtom != atom.Script {\n\t\t\t\ts = html.EscapeString(s)\n\t\t\t}\n\t\t}\n\t\tfmt.Print(s)\n\t\tfor c := n.FirstChild; c != nil; c = c.NextSibling {\n\t\t\tt.printPre(c)\n\t\t}\n\tcase html.ElementNode:\n\t\tfmt.Printf(\"<%s\", n.Data)\n\t\tfor _, a := range n.Attr {\n\t\t\tval := a.Val\n\t\t\tif pupEscapeHTML {\n\t\t\t\tval = html.EscapeString(val)\n\t\t\t}\n\t\t\tfmt.Printf(` %s=\"%s\"`, a.Key, val)\n\t\t}\n\t\tfmt.Print(\">\")\n\t\tif !isVoidElement(n) {\n\t\t\tfor c := n.FirstChild; c != nil; c = c.NextSibling {\n\t\t\t\tt.printPre(c)\n\t\t\t}\n\t\t\tfmt.Printf(\"\", n.Data)\n\t\t}\n\tcase html.CommentNode:\n\t\tdata := n.Data\n\t\tif pupEscapeHTML {\n\t\t\tdata = html.EscapeString(data)\n\t\t}\n\t\tfmt.Printf(\"\\n\", data)\n\t\tfor c := n.FirstChild; c != nil; c = c.NextSibling {\n\t\t\tt.printPre(c)\n\t\t}\n\tcase html.DoctypeNode, html.DocumentNode:\n\t\tfor c := n.FirstChild; c != nil; c = c.NextSibling {\n\t\t\tt.printPre(c)\n\t\t}\n\t}\n}\n\n// Print a node and all of it's children to `maxlevel`.\nfunc (t TreeDisplayer) printNode(n *html.Node, level int) {\n\tswitch n.Type {\n\tcase html.TextNode:\n\t\ts := n.Data\n\t\tif pupEscapeHTML {\n\t\t\t// don't escape javascript\n\t\t\tif n.Parent == nil || n.Parent.DataAtom != atom.Script {\n\t\t\t\ts = html.EscapeString(s)\n\t\t\t}\n\t\t}\n\t\ts = strings.TrimSpace(s)\n\t\tif s != \"\" {\n\t\t\tt.printIndent(level)\n\t\t\tfmt.Println(s)\n\t\t}\n\tcase html.ElementNode:\n\t\tt.printIndent(level)\n\t\t// TODO: allow pre with color\n\t\tif n.DataAtom == atom.Pre && !pupPrintColor && pupPreformatted {\n\t\t\tt.printPre(n)\n\t\t\tfmt.Println()\n\t\t\treturn\n\t\t}\n\t\tif pupPrintColor {\n\t\t\ttokenColor.Print(\"<\")\n\t\t\ttagColor.Printf(\"%s\", n.Data)\n\t\t} else {\n\t\t\tfmt.Printf(\"<%s\", n.Data)\n\t\t}\n\t\tfor _, a := range n.Attr {\n\t\t\tval := a.Val\n\t\t\tif pupEscapeHTML {\n\t\t\t\tval = html.EscapeString(val)\n\t\t\t}\n\t\t\tif pupPrintColor {\n\t\t\t\tfmt.Print(\" \")\n\t\t\t\tattrKeyColor.Printf(\"%s\", a.Key)\n\t\t\t\ttokenColor.Print(\"=\")\n\t\t\t\tquoteColor.Printf(`\"%s\"`, val)\n\t\t\t} else {\n\t\t\t\tfmt.Printf(` %s=\"%s\"`, a.Key, val)\n\t\t\t}\n\t\t}\n\t\tif pupPrintColor {\n\t\t\ttokenColor.Println(\">\")\n\t\t} else {\n\t\t\tfmt.Println(\">\")\n\t\t}\n\t\tif !isVoidElement(n) {\n\t\t\tt.printChildren(n, level+1)\n\t\t\tt.printIndent(level)\n\t\t\tif pupPrintColor {\n\t\t\t\ttokenColor.Print(\"\")\n\t\t\t} else {\n\t\t\t\tfmt.Printf(\"\\n\", n.Data)\n\t\t\t}\n\t\t}\n\tcase html.CommentNode:\n\t\tt.printIndent(level)\n\t\tdata := n.Data\n\t\tif pupEscapeHTML {\n\t\t\tdata = html.EscapeString(data)\n\t\t}\n\t\tif pupPrintColor {\n\t\t\tcommentColor.Printf(\"\\n\", data)\n\t\t} else {\n\t\t\tfmt.Printf(\"\\n\", data)\n\t\t}\n\t\tt.printChildren(n, level)\n\tcase html.DoctypeNode, html.DocumentNode:\n\t\tt.printChildren(n, level)\n\t}\n}\n\nfunc (t TreeDisplayer) printChildren(n *html.Node, level int) {\n\tif pupMaxPrintLevel > -1 {\n\t\tif level >= pupMaxPrintLevel {\n\t\t\tt.printIndent(level)\n\t\t\tfmt.Println(\"...\")\n\t\t\treturn\n\t\t}\n\t}\n\tchild := n.FirstChild\n\tfor child != nil {\n\t\tt.printNode(child, level)\n\t\tchild = child.NextSibling\n\t}\n}\n\nfunc (t TreeDisplayer) printIndent(level int) {\n\tfor ; level > 0; level-- {\n\t\tfmt.Print(pupIndentString)\n\t}\n}\n\n// Print the text of a node\ntype TextDisplayer struct{}\n\nfunc (t TextDisplayer) Display(nodes []*html.Node) {\n\tfor _, node := range nodes {\n\t\tif node.Type == html.TextNode {\n\t\t\tdata := node.Data\n\t\t\tif pupEscapeHTML {\n\t\t\t\t// don't escape javascript\n\t\t\t\tif node.Parent == nil || node.Parent.DataAtom != atom.Script {\n\t\t\t\t\tdata = html.EscapeString(data)\n\t\t\t\t}\n\t\t\t}\n\t\t\tfmt.Println(data)\n\t\t}\n\t\tchildren := []*html.Node{}\n\t\tchild := node.FirstChild\n\t\tfor child != nil {\n\t\t\tchildren = append(children, child)\n\t\t\tchild = child.NextSibling\n\t\t}\n\t\tt.Display(children)\n\t}\n}\n\n// Print the attribute of a node\ntype AttrDisplayer struct {\n\tAttr string\n}\n\nfunc (a AttrDisplayer) Display(nodes []*html.Node) {\n\tfor _, node := range nodes {\n\t\tattributes := node.Attr\n\t\tfor _, attr := range attributes {\n\t\t\tif attr.Key == a.Attr {\n\t\t\t\tval := attr.Val\n\t\t\t\tif pupEscapeHTML {\n\t\t\t\t\tval = html.EscapeString(val)\n\t\t\t\t}\n\t\t\t\tfmt.Printf(\"%s\\n\", val)\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Print nodes as a JSON list\ntype JSONDisplayer struct{}\n\n// returns a jsonifiable struct\nfunc jsonify(node *html.Node) map[string]interface{} {\n\tvals := map[string]interface{}{}\n\tif len(node.Attr) > 0 {\n\t\tfor _, attr := range node.Attr {\n\t\t\tif pupEscapeHTML {\n\t\t\t\tvals[attr.Key] = html.EscapeString(attr.Val)\n\t\t\t} else {\n\t\t\t\tvals[attr.Key] = attr.Val\n\t\t\t}\n\t\t}\n\t}\n\tvals[\"tag\"] = node.DataAtom.String()\n\tchildren := []interface{}{}\n\tfor child := node.FirstChild; child != nil; child = child.NextSibling {\n\t\tswitch child.Type {\n\t\tcase html.ElementNode:\n\t\t\tchildren = append(children, jsonify(child))\n\t\tcase html.TextNode:\n\t\t\ttext := strings.TrimSpace(child.Data)\n\t\t\tif text != \"\" {\n\t\t\t\tif pupEscapeHTML {\n\t\t\t\t\t// don't escape javascript\n\t\t\t\t\tif node.DataAtom != atom.Script {\n\t\t\t\t\t\ttext = html.EscapeString(text)\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t\t// if there is already text we'll append it\n\t\t\t\tcurrText, ok := vals[\"text\"]\n\t\t\t\tif ok {\n\t\t\t\t\ttext = fmt.Sprintf(\"%s %s\", currText, text)\n\t\t\t\t}\n\t\t\t\tvals[\"text\"] = text\n\t\t\t}\n\t\tcase html.CommentNode:\n\t\t\tcomment := strings.TrimSpace(child.Data)\n\t\t\tif pupEscapeHTML {\n\t\t\t\tcomment = html.EscapeString(comment)\n\t\t\t}\n\t\t\tcurrComment, ok := vals[\"comment\"]\n\t\t\tif ok {\n\t\t\t\tcomment = fmt.Sprintf(\"%s %s\", currComment, comment)\n\t\t\t}\n\t\t\tvals[\"comment\"] = comment\n\t\t}\n\t}\n\tif len(children) > 0 {\n\t\tvals[\"children\"] = children\n\t}\n\treturn vals\n}\n\nfunc (j JSONDisplayer) Display(nodes []*html.Node) {\n\tvar data []byte\n\tvar err error\n\tjsonNodes := []map[string]interface{}{}\n\tfor _, node := range nodes {\n\t\tjsonNodes = append(jsonNodes, jsonify(node))\n\t}\n\tdata, err = json.MarshalIndent(&jsonNodes, \"\", pupIndentString)\n\tif err != nil {\n\t\tpanic(\"Could not jsonify nodes\")\n\t}\n\tfmt.Printf(\"%s\\n\", data)\n}\n\n// Print the number of features returned\ntype NumDisplayer struct{}\n\nfunc (d NumDisplayer) Display(nodes []*html.Node) {\n\tfmt.Println(len(nodes))\n}\n"
  },
  {
    "path": "go.mod",
    "content": "module github.com/ericchiang/pup\n\ngo 1.13\n\nrequire (\n\tgithub.com/fatih/color v1.0.0\n\tgithub.com/mattn/go-colorable v0.0.5\n\tgithub.com/mattn/go-isatty v0.0.0-20151211000621-56b76bdf51f7 // indirect\n\tgolang.org/x/net v0.0.0-20160720084139-4d38db76854b\n\tgolang.org/x/sys v0.0.0-20160717071931-a646d33e2ee3 // indirect\n\tgolang.org/x/text v0.0.0-20160719205907-0a5a09ee4409\n)\n"
  },
  {
    "path": "go.sum",
    "content": "github.com/fatih/color v1.0.0 h1:4zdNjpoprR9fed2QRCPb2VTPU4UFXEtJc9Vc+sgXkaQ=\ngithub.com/fatih/color v1.0.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=\ngithub.com/mattn/go-colorable v0.0.5 h1:X1IeP+MaFWC+vpbhw3y426rQftzXSj+N7eJFnBEMBfE=\ngithub.com/mattn/go-colorable v0.0.5/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=\ngithub.com/mattn/go-isatty v0.0.0-20151211000621-56b76bdf51f7 h1:owMyzMR4QR+jSdlfkX9jPU3rsby4++j99BfbtgVr6ZY=\ngithub.com/mattn/go-isatty v0.0.0-20151211000621-56b76bdf51f7/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=\ngolang.org/x/net v0.0.0-20160720084139-4d38db76854b h1:2lHDZItrxmjk3OXnITVKcHWo6qQYJSm4q2pmvciVkxo=\ngolang.org/x/net v0.0.0-20160720084139-4d38db76854b/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=\ngolang.org/x/sys v0.0.0-20160717071931-a646d33e2ee3 h1:ZLExsLvnoqWSw6JB6k6RjWobIHGR3NG9dzVANJ7SVKc=\ngolang.org/x/sys v0.0.0-20160717071931-a646d33e2ee3/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=\ngolang.org/x/text v0.0.0-20160719205907-0a5a09ee4409 h1:ImTDOALQ1AOSGXgapb9Q1tOcHlxpQXZCPSIMKLce0JU=\ngolang.org/x/text v0.0.0-20160719205907-0a5a09ee4409/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=\n"
  },
  {
    "path": "parse.go",
    "content": "package main\n\nimport (\n\t\"fmt\"\n\t\"io\"\n\t\"os\"\n\t\"strconv\"\n\t\"strings\"\n\n\t\"golang.org/x/net/html\"\n\t\"golang.org/x/net/html/charset\"\n\t\"golang.org/x/text/transform\"\n)\n\nvar (\n\tpupIn            io.ReadCloser = os.Stdin\n\tpupCharset       string        = \"\"\n\tpupMaxPrintLevel int           = -1\n\tpupPreformatted  bool          = false\n\tpupPrintColor    bool          = false\n\tpupEscapeHTML    bool          = true\n\tpupIndentString  string        = \" \"\n\tpupDisplayer     Displayer     = TreeDisplayer{}\n)\n\n// Parse the html while handling the charset\nfunc ParseHTML(r io.Reader, cs string) (*html.Node, error) {\n\tvar err error\n\tif cs == \"\" {\n\t\t// attempt to guess the charset of the HTML document\n\t\tr, err = charset.NewReader(r, \"\")\n\t\tif err != nil {\n\t\t\treturn nil, err\n\t\t}\n\t} else {\n\t\t// let the user specify the charset\n\t\te, name := charset.Lookup(cs)\n\t\tif name == \"\" {\n\t\t\treturn nil, fmt.Errorf(\"'%s' is not a valid charset\", cs)\n\t\t}\n\t\tr = transform.NewReader(r, e.NewDecoder())\n\t}\n\treturn html.Parse(r)\n}\n\nfunc PrintHelp(w io.Writer, exitCode int) {\n\thelpString := `Usage\n    pup [flags] [selectors] [optional display function]\nVersion\n    %s\nFlags\n    -c --color         print result with color\n    -f --file          file to read from\n    -h --help          display this help\n    -i --indent        number of spaces to use for indent or character\n    -n --number        print number of elements selected\n    -l --limit         restrict number of levels printed\n    -p --plain         don't escape html\n    --pre              preserve preformatted text\n    --charset          specify the charset for pup to use\n    --version          display version\n`\n\tfmt.Fprintf(w, helpString, VERSION)\n\tos.Exit(exitCode)\n}\n\nfunc ParseArgs() ([]string, error) {\n\tcmds, err := ProcessFlags(os.Args[1:])\n\tif err != nil {\n\t\treturn []string{}, err\n\t}\n\treturn ParseCommands(strings.Join(cmds, \" \"))\n}\n\n// Process command arguments and return all non-flags.\nfunc ProcessFlags(cmds []string) (nonFlagCmds []string, err error) {\n\tvar i int\n\tdefer func() {\n\t\tif r := recover(); r != nil {\n\t\t\terr = fmt.Errorf(\"Option '%s' requires an argument\", cmds[i])\n\t\t}\n\t}()\n\tnonFlagCmds = make([]string, len(cmds))\n\tn := 0\n\tfor i = 0; i < len(cmds); i++ {\n\t\tcmd := cmds[i]\n\t\tswitch cmd {\n\t\tcase \"-c\", \"--color\":\n\t\t\tpupPrintColor = true\n\t\tcase \"-p\", \"--plain\":\n\t\t\tpupEscapeHTML = false\n\t\tcase \"--pre\":\n\t\t\tpupPreformatted = true\n\t\tcase \"-f\", \"--file\":\n\t\t\tfilename := cmds[i+1]\n\t\t\tpupIn, err = os.Open(filename)\n\t\t\tif err != nil {\n\t\t\t\tfmt.Fprintf(os.Stderr, \"%s\\n\", err.Error())\n\t\t\t\tos.Exit(2)\n\t\t\t}\n\t\t\ti++\n\t\tcase \"-h\", \"--help\":\n\t\t\tPrintHelp(os.Stdout, 0)\n\t\tcase \"-i\", \"--indent\":\n\t\t\tindentLevel, err := strconv.Atoi(cmds[i+1])\n\t\t\tif err == nil {\n\t\t\t\tpupIndentString = strings.Repeat(\" \", indentLevel)\n\t\t\t} else {\n\t\t\t\tpupIndentString = cmds[i+1]\n\t\t\t}\n\t\t\ti++\n\t\tcase \"-l\", \"--limit\":\n\t\t\tpupMaxPrintLevel, err = strconv.Atoi(cmds[i+1])\n\t\t\tif err != nil {\n\t\t\t\treturn []string{}, fmt.Errorf(\"Argument for '%s' must be numeric\", cmd)\n\t\t\t}\n\t\t\ti++\n\t\tcase \"--charset\":\n\t\t\tpupCharset = cmds[i+1]\n\t\t\ti++\n\t\tcase \"--version\":\n\t\t\tfmt.Println(VERSION)\n\t\t\tos.Exit(0)\n\t\tcase \"-n\", \"--number\":\n\t\t\tpupDisplayer = NumDisplayer{}\n\t\tdefault:\n\t\t\tif cmd[0] == '-' {\n\t\t\t\treturn []string{}, fmt.Errorf(\"Unrecognized flag '%s'\", cmd)\n\t\t\t}\n\t\t\tnonFlagCmds[n] = cmds[i]\n\t\t\tn++\n\t\t}\n\t}\n\treturn nonFlagCmds[:n], nil\n}\n\n// Split a string with awareness for quoted text and commas\nfunc ParseCommands(cmdString string) ([]string, error) {\n\tcmds := []string{}\n\tlast, next, max := 0, 0, len(cmdString)\n\tfor {\n\t\t// if we're at the end of the string, return\n\t\tif next == max {\n\t\t\tif next > last {\n\t\t\t\tcmds = append(cmds, cmdString[last:next])\n\t\t\t}\n\t\t\treturn cmds, nil\n\t\t}\n\t\t// evaluate a rune\n\t\tc := cmdString[next]\n\t\tswitch c {\n\t\tcase ' ':\n\t\t\tif next > last {\n\t\t\t\tcmds = append(cmds, cmdString[last:next])\n\t\t\t}\n\t\t\tlast = next + 1\n\t\tcase ',':\n\t\t\tif next > last {\n\t\t\t\tcmds = append(cmds, cmdString[last:next])\n\t\t\t}\n\t\t\tcmds = append(cmds, \",\")\n\t\t\tlast = next + 1\n\t\tcase '\\'', '\"':\n\t\t\t// for quotes, consume runes until the quote has ended\n\t\t\tquoteChar := c\n\t\t\tfor {\n\t\t\t\tnext++\n\t\t\t\tif next == max {\n\t\t\t\t\treturn []string{}, fmt.Errorf(\"Unmatched open quote (%c)\", quoteChar)\n\t\t\t\t}\n\t\t\t\tif cmdString[next] == '\\\\' {\n\t\t\t\t\tnext++\n\t\t\t\t\tif next == max {\n\t\t\t\t\t\treturn []string{}, fmt.Errorf(\"Unmatched open quote (%c)\", quoteChar)\n\t\t\t\t\t}\n\t\t\t\t} else if cmdString[next] == quoteChar {\n\t\t\t\t\tbreak\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t\tnext++\n\t}\n}\n"
  },
  {
    "path": "parse_test.go",
    "content": "package main\n\nimport (\n\t\"testing\"\n)\n\ntype parseCmdTest struct {\n\tinput string\n\tsplit []string\n\tok    bool\n}\n\nvar parseCmdTests = []parseCmdTest{\n\tparseCmdTest{`w1 w2`, []string{`w1`, `w2`}, true},\n\tparseCmdTest{`w1 w2 w3`, []string{`w1`, `w2`, `w3`}, true},\n\tparseCmdTest{`w1 'w2 w3'`, []string{`w1`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1 \"w2 w3\"`, []string{`w1`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1   \"w2 w3\"`, []string{`w1`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1   'w2 w3'`, []string{`w1`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1\"w2 w3\"`, []string{`w1\"w2 w3\"`}, true},\n\tparseCmdTest{`w1'w2 w3'`, []string{`w1'w2 w3'`}, true},\n\tparseCmdTest{`w1\"w2 'w3\"`, []string{`w1\"w2 'w3\"`}, true},\n\tparseCmdTest{`w1'w2 \"w3'`, []string{`w1'w2 \"w3'`}, true},\n\tparseCmdTest{`\"w1 w2\" \"w3\"`, []string{`\"w1 w2\"`, `\"w3\"`}, true},\n\tparseCmdTest{`'w1 w2' \"w3\"`, []string{`'w1 w2'`, `\"w3\"`}, true},\n\tparseCmdTest{`'w1 \\'w2' \"w3\"`, []string{`'w1 \\'w2'`, `\"w3\"`}, true},\n\tparseCmdTest{`'w1 \\'w2 \"w3\"`, []string{}, false},\n\tparseCmdTest{`w1 'w2 w3'\"`, []string{}, false},\n\tparseCmdTest{`w1 \"w2 w3\"'`, []string{}, false},\n\tparseCmdTest{`w1 '  \"w2 w3\"`, []string{}, false},\n\tparseCmdTest{`w1 \"  'w2 w3'`, []string{}, false},\n\tparseCmdTest{`w1\"w2 w3\"\"`, []string{}, false},\n\tparseCmdTest{`w1'w2 w3''`, []string{}, false},\n\tparseCmdTest{`w1\"w2 'w3\"\"`, []string{}, false},\n\tparseCmdTest{`w1'w2 \"w3''`, []string{}, false},\n\tparseCmdTest{`\"w1 w2\" \"w3\"'`, []string{}, false},\n\tparseCmdTest{`'w1 w2' \"w3\"'`, []string{}, false},\n\tparseCmdTest{`w1,\"w2 w3\"`, []string{`w1`, `,`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1,'w2 w3'`, []string{`w1`, `,`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1  ,  \"w2 w3\"`, []string{`w1`, `,`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1  ,  'w2 w3'`, []string{`w1`, `,`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1,  \"w2 w3\"`, []string{`w1`, `,`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1,  'w2 w3'`, []string{`w1`, `,`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1  ,\"w2 w3\"`, []string{`w1`, `,`, `\"w2 w3\"`}, true},\n\tparseCmdTest{`w1  ,'w2 w3'`, []string{`w1`, `,`, `'w2 w3'`}, true},\n\tparseCmdTest{`w1\"w2, w3\"`, []string{`w1\"w2, w3\"`}, true},\n\tparseCmdTest{`w1'w2, w3'`, []string{`w1'w2, w3'`}, true},\n\tparseCmdTest{`w1\"w2, 'w3\"`, []string{`w1\"w2, 'w3\"`}, true},\n\tparseCmdTest{`w1'w2, \"w3'`, []string{`w1'w2, \"w3'`}, true},\n\tparseCmdTest{`\"w1, w2\" \"w3\"`, []string{`\"w1, w2\"`, `\"w3\"`}, true},\n\tparseCmdTest{`'w1, w2' \"w3\"`, []string{`'w1, w2'`, `\"w3\"`}, true},\n\tparseCmdTest{`'w1, \\'w2' \"w3\"`, []string{`'w1, \\'w2'`, `\"w3\"`}, true},\n\tparseCmdTest{`h1, .article-teaser, .article-content`, []string{\n\t\t`h1`, `,`, `.article-teaser`, `,`, `.article-content`,\n\t}, true},\n\tparseCmdTest{`h1 ,.article-teaser ,.article-content`, []string{\n\t\t`h1`, `,`, `.article-teaser`, `,`, `.article-content`,\n\t}, true},\n\tparseCmdTest{`h1 , .article-teaser , .article-content`, []string{\n\t\t`h1`, `,`, `.article-teaser`, `,`, `.article-content`,\n\t}, true},\n}\n\nfunc sliceEq(s1, s2 []string) bool {\n\tif len(s1) != len(s2) {\n\t\treturn false\n\t}\n\tfor i := range s1 {\n\t\tif s1[i] != s2[i] {\n\t\t\treturn false\n\t\t}\n\t}\n\treturn true\n}\n\nfunc TestParseCommands(t *testing.T) {\n\tfor _, test := range parseCmdTests {\n\t\tparsed, err := ParseCommands(test.input)\n\t\tif test.ok != (err == nil) {\n\t\t\tt.Errorf(\"`%s`: should have cause error? %v\", test.input, !test.ok)\n\t\t} else if !sliceEq(test.split, parsed) {\n\t\t\tt.Errorf(\"`%s`: `%s`: `%s`\", test.input, test.split, parsed)\n\t\t}\n\t}\n}\n"
  },
  {
    "path": "pup.go",
    "content": "package main\n\nimport (\n\t\"fmt\"\n\t\"os\"\n\n\t\"golang.org/x/net/html\"\n)\n\n//      _=,_\n//   o_/6 /#\\\n//   \\__ |##/\n//    ='|--\\\n//      /   #'-.\n//      \\#|_   _'-. /\n//       |/ \\_( # |\"\n//      C/ ,--___/\n\nvar VERSION string = \"0.4.0\"\n\nfunc main() {\n\t// process flags and arguments\n\tcmds, err := ParseArgs()\n\tif err != nil {\n\t\tfmt.Fprintf(os.Stderr, \"%s\\n\", err.Error())\n\t\tos.Exit(2)\n\t}\n\n\t// Parse the input and get the root node\n\troot, err := ParseHTML(pupIn, pupCharset)\n\tif err != nil {\n\t\tfmt.Fprintf(os.Stderr, \"%s\\n\", err.Error())\n\t\tos.Exit(2)\n\t}\n\tpupIn.Close()\n\n\t// Parse the selectors\n\tselectorFuncs := []SelectorFunc{}\n\tfuncGenerator := Select\n\tvar cmd string\n\tfor len(cmds) > 0 {\n\t\tcmd, cmds = cmds[0], cmds[1:]\n\t\tif len(cmds) == 0 {\n\t\t\tif err := ParseDisplayer(cmd); err == nil {\n\t\t\t\tcontinue\n\t\t\t}\n\t\t}\n\t\tswitch cmd {\n\t\tcase \"*\": // select all\n\t\t\tcontinue\n\t\tcase \">\":\n\t\t\tfuncGenerator = SelectFromChildren\n\t\tcase \"+\":\n\t\t\tfuncGenerator = SelectNextSibling\n\t\tcase \",\": // nil will signify a comma\n\t\t\tselectorFuncs = append(selectorFuncs, nil)\n\t\tdefault:\n\t\t\tselector, err := ParseSelector(cmd)\n\t\t\tif err != nil {\n\t\t\t\tfmt.Fprintf(os.Stderr, \"Selector parsing error: %s\\n\", err.Error())\n\t\t\t\tos.Exit(2)\n\t\t\t}\n\t\t\tselectorFuncs = append(selectorFuncs, funcGenerator(selector))\n\t\t\tfuncGenerator = Select\n\t\t}\n\t}\n\n\tselectedNodes := []*html.Node{}\n\tcurrNodes := []*html.Node{root}\n\tfor _, selectorFunc := range selectorFuncs {\n\t\tif selectorFunc == nil { // hit a comma\n\t\t\tselectedNodes = append(selectedNodes, currNodes...)\n\t\t\tcurrNodes = []*html.Node{root}\n\t\t} else {\n\t\t\tcurrNodes = selectorFunc(currNodes)\n\t\t}\n\t}\n\tselectedNodes = append(selectedNodes, currNodes...)\n\tpupDisplayer.Display(selectedNodes)\n}\n"
  },
  {
    "path": "pup.rb",
    "content": "# This file was generated by release.sh\nrequire 'formula'\nclass Pup < Formula\n  homepage 'https://github.com/ericchiang/pup'\n  version '0.4.0'\n\n  if Hardware::CPU.is_64_bit?\n    url 'https://github.com/ericchiang/pup/releases/download/v0.4.0/pup_v0.4.0_darwin_amd64.zip'\n    sha256 'c539a697efee2f8e56614a54cb3b215338e00de1f6a7c2fa93144ab6e1db8ebe'\n  else\n    url 'https://github.com/ericchiang/pup/releases/download/v0.4.0/pup_v0.4.0_darwin_386.zip'\n    sha256 '75c27caa0008a9cc639beb7506077ad9f32facbffcc4e815e999eaf9588a527e'\n  end\n\n  def install\n    bin.install 'pup'\n  end\nend\n"
  },
  {
    "path": "selector.go",
    "content": "package main\n\nimport (\n\t\"bytes\"\n\t\"fmt\"\n\t\"regexp\"\n\t\"strconv\"\n\t\"strings\"\n\t\"text/scanner\"\n\n\t\"golang.org/x/net/html\"\n)\n\ntype Selector interface {\n\tMatch(node *html.Node) bool\n}\n\ntype SelectorFunc func(nodes []*html.Node) []*html.Node\n\nfunc Select(s Selector) SelectorFunc {\n\t// have to define first to be able to do recursion\n\tvar selectChildren func(node *html.Node) []*html.Node\n\tselectChildren = func(node *html.Node) []*html.Node {\n\t\tselected := []*html.Node{}\n\t\tfor child := node.FirstChild; child != nil; child = child.NextSibling {\n\t\t\tif s.Match(child) {\n\t\t\t\tselected = append(selected, child)\n\t\t\t} else {\n\t\t\t\tselected = append(selected, selectChildren(child)...)\n\t\t\t}\n\t\t}\n\t\treturn selected\n\t}\n\treturn func(nodes []*html.Node) []*html.Node {\n\t\tselected := []*html.Node{}\n\t\tfor _, node := range nodes {\n\t\t\tselected = append(selected, selectChildren(node)...)\n\t\t}\n\t\treturn selected\n\t}\n}\n\n// Defined for the '>' selector\nfunc SelectNextSibling(s Selector) SelectorFunc {\n\treturn func(nodes []*html.Node) []*html.Node {\n\t\tselected := []*html.Node{}\n\t\tfor _, node := range nodes {\n\t\t\tfor ns := node.NextSibling; ns != nil; ns = ns.NextSibling {\n\t\t\t\tif ns.Type == html.ElementNode {\n\t\t\t\t\tif s.Match(ns) {\n\t\t\t\t\t\tselected = append(selected, ns)\n\t\t\t\t\t}\n\t\t\t\t\tbreak\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t\treturn selected\n\t}\n}\n\n// Defined for the '+' selector\nfunc SelectFromChildren(s Selector) SelectorFunc {\n\treturn func(nodes []*html.Node) []*html.Node {\n\t\tselected := []*html.Node{}\n\t\tfor _, node := range nodes {\n\t\t\tfor c := node.FirstChild; c != nil; c = c.NextSibling {\n\t\t\t\tif s.Match(c) {\n\t\t\t\t\tselected = append(selected, c)\n\t\t\t\t}\n\t\t\t}\n\t\t}\n\t\treturn selected\n\t}\n}\n\ntype PseudoClass func(*html.Node) bool\n\ntype CSSSelector struct {\n\tTag    string\n\tAttrs  map[string]*regexp.Regexp\n\tPseudo PseudoClass\n}\n\nfunc (s CSSSelector) Match(node *html.Node) bool {\n\tif node.Type != html.ElementNode {\n\t\treturn false\n\t}\n\tif s.Tag != \"\" {\n\t\tif s.Tag != node.DataAtom.String() {\n\t\t\treturn false\n\t\t}\n\t}\n\tfor attrKey, matcher := range s.Attrs {\n\t\tmatched := false\n\t\tfor _, attr := range node.Attr {\n\t\t\tif attrKey == attr.Key {\n\t\t\t\tif !matcher.MatchString(attr.Val) {\n\t\t\t\t\treturn false\n\t\t\t\t}\n\t\t\t\tmatched = true\n\t\t\t\tbreak\n\t\t\t}\n\t\t}\n\t\tif !matched {\n\t\t\treturn false\n\t\t}\n\t}\n\tif s.Pseudo == nil {\n\t\treturn true\n\t}\n\treturn s.Pseudo(node)\n}\n\n// Parse a selector\n// e.g. `div#my-button.btn[href^=\"http\"]`\nfunc ParseSelector(cmd string) (selector CSSSelector, err error) {\n\tselector = CSSSelector{\n\t\tTag:    \"\",\n\t\tAttrs:  map[string]*regexp.Regexp{},\n\t\tPseudo: nil,\n\t}\n\tvar s scanner.Scanner\n\ts.Init(strings.NewReader(cmd))\n\terr = ParseTagMatcher(&selector, s)\n\treturn\n}\n\n// Parse the initial tag\n// e.g. `div`\nfunc ParseTagMatcher(selector *CSSSelector, s scanner.Scanner) error {\n\ttag := bytes.NewBuffer([]byte{})\n\tdefer func() {\n\t\tselector.Tag = tag.String()\n\t}()\n\tfor {\n\t\tc := s.Next()\n\t\tswitch c {\n\t\tcase scanner.EOF:\n\t\t\treturn nil\n\t\tcase '.':\n\t\t\treturn ParseClassMatcher(selector, s)\n\t\tcase '#':\n\t\t\treturn ParseIdMatcher(selector, s)\n\t\tcase '[':\n\t\t\treturn ParseAttrMatcher(selector, s)\n\t\tcase ':':\n\t\t\treturn ParsePseudo(selector, s)\n\t\tdefault:\n\t\t\tif _, err := tag.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Parse a class matcher\n// e.g. `.btn`\nfunc ParseClassMatcher(selector *CSSSelector, s scanner.Scanner) error {\n\tvar class bytes.Buffer\n\tdefer func() {\n\t\tregexpStr := `(\\A|\\s)` + regexp.QuoteMeta(class.String()) + `(\\s|\\z)`\n\t\tselector.Attrs[\"class\"] = regexp.MustCompile(regexpStr)\n\t}()\n\tfor {\n\t\tc := s.Next()\n\t\tswitch c {\n\t\tcase scanner.EOF:\n\t\t\treturn nil\n\t\tcase '.':\n\t\t\treturn ParseClassMatcher(selector, s)\n\t\tcase '#':\n\t\t\treturn ParseIdMatcher(selector, s)\n\t\tcase '[':\n\t\t\treturn ParseAttrMatcher(selector, s)\n\t\tcase ':':\n\t\t\treturn ParsePseudo(selector, s)\n\t\tdefault:\n\t\t\tif _, err := class.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Parse an id matcher\n// e.g. `#my-picture`\nfunc ParseIdMatcher(selector *CSSSelector, s scanner.Scanner) error {\n\tvar id bytes.Buffer\n\tdefer func() {\n\t\tregexpStr := `^` + regexp.QuoteMeta(id.String()) + `$`\n\t\tselector.Attrs[\"id\"] = regexp.MustCompile(regexpStr)\n\t}()\n\tfor {\n\t\tc := s.Next()\n\t\tswitch c {\n\t\tcase scanner.EOF:\n\t\t\treturn nil\n\t\tcase '.':\n\t\t\treturn ParseClassMatcher(selector, s)\n\t\tcase '#':\n\t\t\treturn ParseIdMatcher(selector, s)\n\t\tcase '[':\n\t\t\treturn ParseAttrMatcher(selector, s)\n\t\tcase ':':\n\t\t\treturn ParsePseudo(selector, s)\n\t\tdefault:\n\t\t\tif _, err := id.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Parse an attribute matcher\n// e.g. `[attr^=\"http\"]`\nfunc ParseAttrMatcher(selector *CSSSelector, s scanner.Scanner) error {\n\tvar attrKey bytes.Buffer\n\tvar attrVal bytes.Buffer\n\thasMatchVal := false\n\tmatchType := '='\n\tdefer func() {\n\t\tif hasMatchVal {\n\t\t\tvar regexpStr string\n\t\t\tswitch matchType {\n\t\t\tcase '=':\n\t\t\t\tregexpStr = `^` + regexp.QuoteMeta(attrVal.String()) + `$`\n\t\t\tcase '*':\n\t\t\t\tregexpStr = regexp.QuoteMeta(attrVal.String())\n\t\t\tcase '$':\n\t\t\t\tregexpStr = regexp.QuoteMeta(attrVal.String()) + `$`\n\t\t\tcase '^':\n\t\t\t\tregexpStr = `^` + regexp.QuoteMeta(attrVal.String())\n\t\t\tcase '~':\n\t\t\t\tregexpStr = `(\\A|\\s)` + regexp.QuoteMeta(attrVal.String()) + `(\\s|\\z)`\n\t\t\t}\n\t\t\tselector.Attrs[attrKey.String()] = regexp.MustCompile(regexpStr)\n\t\t} else {\n\t\t\tselector.Attrs[attrKey.String()] = regexp.MustCompile(`^.*$`)\n\t\t}\n\t}()\n\t// After reaching ']' proceed\n\tproceed := func() error {\n\t\tswitch s.Next() {\n\t\tcase scanner.EOF:\n\t\t\treturn nil\n\t\tcase '.':\n\t\t\treturn ParseClassMatcher(selector, s)\n\t\tcase '#':\n\t\t\treturn ParseIdMatcher(selector, s)\n\t\tcase '[':\n\t\t\treturn ParseAttrMatcher(selector, s)\n\t\tcase ':':\n\t\t\treturn ParsePseudo(selector, s)\n\t\tdefault:\n\t\t\treturn fmt.Errorf(\"Expected selector indicator after ']'\")\n\t\t}\n\t}\n\t// Parse the attribute key matcher\n\tfor !hasMatchVal {\n\t\tc := s.Next()\n\t\tswitch c {\n\t\tcase scanner.EOF:\n\t\t\treturn fmt.Errorf(\"Unmatched open brace '['\")\n\t\tcase ']':\n\t\t\t// No attribute value matcher, proceed!\n\t\t\treturn proceed()\n\t\tcase '$', '^', '~', '*':\n\t\t\tmatchType = c\n\t\t\thasMatchVal = true\n\t\t\tif s.Next() != '=' {\n\t\t\t\treturn fmt.Errorf(\"'%c' must be followed by a '='\", matchType)\n\t\t\t}\n\t\tcase '=':\n\t\t\tmatchType = c\n\t\t\thasMatchVal = true\n\t\tdefault:\n\t\t\tif _, err := attrKey.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n\t// figure out if the value is quoted\n\tc := s.Next()\n\tinQuote := false\n\tswitch c {\n\tcase scanner.EOF:\n\t\treturn fmt.Errorf(\"Unmatched open brace '['\")\n\tcase ']':\n\t\treturn proceed()\n\tcase '\"':\n\t\tinQuote = true\n\tdefault:\n\t\tif _, err := attrVal.WriteRune(c); err != nil {\n\t\t\treturn err\n\t\t}\n\t}\n\tif inQuote {\n\t\tfor {\n\t\t\tc := s.Next()\n\t\t\tswitch c {\n\t\t\tcase '\\\\':\n\t\t\t\t// consume another character\n\t\t\t\tif c = s.Next(); c == scanner.EOF {\n\t\t\t\t\treturn fmt.Errorf(\"Unmatched open brace '['\")\n\t\t\t\t}\n\t\t\tcase '\"':\n\t\t\t\tswitch s.Next() {\n\t\t\t\tcase ']':\n\t\t\t\t\treturn proceed()\n\t\t\t\tdefault:\n\t\t\t\t\treturn fmt.Errorf(\"Quote must end at ']'\")\n\t\t\t\t}\n\t\t\t}\n\t\t\tif _, err := attrVal.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t} else {\n\t\tfor {\n\t\t\tc := s.Next()\n\t\t\tswitch c {\n\t\t\tcase scanner.EOF:\n\t\t\t\treturn fmt.Errorf(\"Unmatched open brace '['\")\n\t\t\tcase ']':\n\t\t\t\t// No attribute value matcher, proceed!\n\t\t\t\treturn proceed()\n\t\t\t}\n\t\t\tif _, err := attrVal.WriteRune(c); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Parse the selector after ':'\nfunc ParsePseudo(selector *CSSSelector, s scanner.Scanner) error {\n\tif selector.Pseudo != nil {\n\t\treturn fmt.Errorf(\"Combined multiple pseudo classes\")\n\t}\n\tvar b bytes.Buffer\n\tfor s.Peek() != scanner.EOF {\n\t\tif _, err := b.WriteRune(s.Next()); err != nil {\n\t\t\treturn err\n\t\t}\n\t}\n\tcmd := b.String()\n\tvar err error\n\tswitch {\n\tcase cmd == \"empty\":\n\t\tselector.Pseudo = func(n *html.Node) bool {\n\t\t\treturn n.FirstChild == nil\n\t\t}\n\tcase cmd == \"first-child\":\n\t\tselector.Pseudo = firstChildPseudo\n\tcase cmd == \"last-child\":\n\t\tselector.Pseudo = lastChildPseudo\n\tcase cmd == \"only-child\":\n\t\tselector.Pseudo = func(n *html.Node) bool {\n\t\t\treturn firstChildPseudo(n) && lastChildPseudo(n)\n\t\t}\n\tcase cmd == \"first-of-type\":\n\t\tselector.Pseudo = firstOfTypePseudo\n\tcase cmd == \"last-of-type\":\n\t\tselector.Pseudo = lastOfTypePseudo\n\tcase cmd == \"only-of-type\":\n\t\tselector.Pseudo = func(n *html.Node) bool {\n\t\t\treturn firstOfTypePseudo(n) && lastOfTypePseudo(n)\n\t\t}\n\tcase strings.HasPrefix(cmd, \"contains(\"):\n\t\tselector.Pseudo, err = parseContainsPseudo(cmd[len(\"contains(\"):])\n\t\tif err != nil {\n\t\t\treturn err\n\t\t}\n\tcase strings.HasPrefix(cmd, \"nth-child(\"),\n\t\tstrings.HasPrefix(cmd, \"nth-last-child(\"),\n\t\tstrings.HasPrefix(cmd, \"nth-last-of-type(\"),\n\t\tstrings.HasPrefix(cmd, \"nth-of-type(\"):\n\t\tif selector.Pseudo, err = parseNthPseudo(cmd); err != nil {\n\t\t\treturn err\n\t\t}\n\tcase strings.HasPrefix(cmd, \"not(\"):\n\t\tif selector.Pseudo, err = parseNotPseudo(cmd[len(\"not(\"):]); err != nil {\n\t\t\treturn err\n\t\t}\n\tcase strings.HasPrefix(cmd, \"parent-of(\"):\n\t\tif selector.Pseudo, err = parseParentOfPseudo(cmd[len(\"parent-of(\"):]); err != nil {\n\t\t\treturn err\n\t\t}\n\tdefault:\n\t\treturn fmt.Errorf(\"%s not a valid pseudo class\", cmd)\n\t}\n\treturn nil\n}\n\n// :first-of-child\nfunc firstChildPseudo(n *html.Node) bool {\n\tfor c := n.PrevSibling; c != nil; c = c.PrevSibling {\n\t\tif c.Type == html.ElementNode {\n\t\t\treturn false\n\t\t}\n\t}\n\treturn true\n}\n\n// :last-of-child\nfunc lastChildPseudo(n *html.Node) bool {\n\tfor c := n.NextSibling; c != nil; c = c.NextSibling {\n\t\tif c.Type == html.ElementNode {\n\t\t\treturn false\n\t\t}\n\t}\n\treturn true\n}\n\n// :first-of-type\nfunc firstOfTypePseudo(node *html.Node) bool {\n\tif node.Type != html.ElementNode {\n\t\treturn false\n\t}\n\tfor n := node.PrevSibling; n != nil; n = n.PrevSibling {\n\t\tif n.DataAtom == node.DataAtom {\n\t\t\treturn false\n\t\t}\n\t}\n\treturn true\n}\n\n// :last-of-type\nfunc lastOfTypePseudo(node *html.Node) bool {\n\tif node.Type != html.ElementNode {\n\t\treturn false\n\t}\n\tfor n := node.NextSibling; n != nil; n = n.NextSibling {\n\t\tif n.DataAtom == node.DataAtom {\n\t\t\treturn false\n\t\t}\n\t}\n\treturn true\n}\n\nfunc parseNthPseudo(cmd string) (PseudoClass, error) {\n\ti := strings.IndexRune(cmd, '(')\n\tif i < 0 {\n\t\t// really, we should never get here\n\t\treturn nil, fmt.Errorf(\"Fatal error, '%s' does not contain a '('\", cmd)\n\t}\n\tpseudoName := cmd[:i]\n\t// Figure out how the counting function works\n\tvar countNth func(*html.Node) int\n\tswitch pseudoName {\n\tcase \"nth-child\":\n\t\tcountNth = func(n *html.Node) int {\n\t\t\tnth := 1\n\t\t\tfor sib := n.PrevSibling; sib != nil; sib = sib.PrevSibling {\n\t\t\t\tif sib.Type == html.ElementNode {\n\t\t\t\t\tnth++\n\t\t\t\t}\n\t\t\t}\n\t\t\treturn nth\n\t\t}\n\tcase \"nth-of-type\":\n\t\tcountNth = func(n *html.Node) int {\n\t\t\tnth := 1\n\t\t\tfor sib := n.PrevSibling; sib != nil; sib = sib.PrevSibling {\n\t\t\t\tif sib.Type == html.ElementNode && sib.DataAtom == n.DataAtom {\n\t\t\t\t\tnth++\n\t\t\t\t}\n\t\t\t}\n\t\t\treturn nth\n\t\t}\n\tcase \"nth-last-child\":\n\t\tcountNth = func(n *html.Node) int {\n\t\t\tnth := 1\n\t\t\tfor sib := n.NextSibling; sib != nil; sib = sib.NextSibling {\n\t\t\t\tif sib.Type == html.ElementNode {\n\t\t\t\t\tnth++\n\t\t\t\t}\n\t\t\t}\n\t\t\treturn nth\n\t\t}\n\tcase \"nth-last-of-type\":\n\t\tcountNth = func(n *html.Node) int {\n\t\t\tnth := 1\n\t\t\tfor sib := n.NextSibling; sib != nil; sib = sib.NextSibling {\n\t\t\t\tif sib.Type == html.ElementNode && sib.DataAtom == n.DataAtom {\n\t\t\t\t\tnth++\n\t\t\t\t}\n\t\t\t}\n\t\t\treturn nth\n\t\t}\n\tdefault:\n\t\treturn nil, fmt.Errorf(\"Unrecognized pseudo '%s'\", pseudoName)\n\t}\n\n\tnthString := cmd[i+1:]\n\ti = strings.IndexRune(nthString, ')')\n\tif i < 0 {\n\t\treturn nil, fmt.Errorf(\"Unmatched '(' for pseudo class %s\", pseudoName)\n\t} else if i != len(nthString)-1 {\n\t\treturn nil, fmt.Errorf(\"%s(n) must end selector\", pseudoName)\n\t}\n\tnumber := nthString[:i]\n\n\t// Check if the number is 'odd' or 'even'\n\toddOrEven := -1\n\tswitch number {\n\tcase \"odd\":\n\t\toddOrEven = 1\n\tcase \"even\":\n\t\toddOrEven = 0\n\t}\n\tif oddOrEven > -1 {\n\t\treturn func(n *html.Node) bool {\n\t\t\treturn n.Type == html.ElementNode && countNth(n)%2 == oddOrEven\n\t\t}, nil\n\t}\n\t// Check against '3n+4' pattern\n\tr := regexp.MustCompile(`([0-9]+)n[ ]?\\+[ ]?([0-9])`)\n\tsubMatch := r.FindAllStringSubmatch(number, -1)\n\tif len(subMatch) == 1 && len(subMatch[0]) == 3 {\n\t\tcycle, _ := strconv.Atoi(subMatch[0][1])\n\t\toffset, _ := strconv.Atoi(subMatch[0][2])\n\t\treturn func(n *html.Node) bool {\n\t\t\treturn n.Type == html.ElementNode && countNth(n)%cycle == offset\n\t\t}, nil\n\t}\n\t// check against 'n+2' pattern\n\tr = regexp.MustCompile(`n[ ]?\\+[ ]?([0-9])`)\n\tsubMatch = r.FindAllStringSubmatch(number, -1)\n\tif len(subMatch) == 1 && len(subMatch[0]) == 2 {\n\t\toffset, _ := strconv.Atoi(subMatch[0][1])\n\t\treturn func(n *html.Node) bool {\n\t\t\treturn n.Type == html.ElementNode && countNth(n) >= offset\n\t\t}, nil\n\t}\n\t// the only other option is a numeric value\n\tnth, err := strconv.Atoi(nthString[:i])\n\tif err != nil {\n\t\treturn nil, err\n\t} else if nth <= 0 {\n\t\treturn nil, fmt.Errorf(\"Argument to '%s' must be greater than 0\", pseudoName)\n\t}\n\treturn func(n *html.Node) bool {\n\t\treturn n.Type == html.ElementNode && countNth(n) == nth\n\t}, nil\n}\n\n// Parse a :contains(\"\") selector\n// expects the input to be everything after the open parenthesis\n// e.g. for `contains(\"Help\")` the argument would be `\"Help\")`\nfunc parseContainsPseudo(cmd string) (PseudoClass, error) {\n\tvar s scanner.Scanner\n\ts.Init(strings.NewReader(cmd))\n\tswitch s.Next() {\n\tcase '\"':\n\tdefault:\n\t\treturn nil, fmt.Errorf(\"Malformed 'contains(\\\"\\\")' selector\")\n\t}\n\ttextToContain := bytes.NewBuffer([]byte{})\n\tfor {\n\t\tr := s.Next()\n\t\tswitch r {\n\t\tcase '\"':\n\t\t\t// ')' then EOF must follow '\"'\n\t\t\tif s.Next() != ')' {\n\t\t\t\treturn nil, fmt.Errorf(\"Malformed 'contains(\\\"\\\")' selector\")\n\t\t\t}\n\t\t\tif s.Next() != scanner.EOF {\n\t\t\t\treturn nil, fmt.Errorf(\"'contains(\\\"\\\")' must end selector\")\n\t\t\t}\n\t\t\ttext := textToContain.String()\n\t\t\tcontains := func(node *html.Node) bool {\n\t\t\t\tfor c := node.FirstChild; c != nil; c = c.NextSibling {\n\t\t\t\t\tif c.Type == html.TextNode {\n\t\t\t\t\t\tif strings.Contains(c.Data, text) {\n\t\t\t\t\t\t\treturn true\n\t\t\t\t\t\t}\n\t\t\t\t\t}\n\t\t\t\t}\n\t\t\t\treturn false\n\t\t\t}\n\t\t\treturn contains, nil\n\t\tcase '\\\\':\n\t\t\ts.Next()\n\t\tcase scanner.EOF:\n\t\t\treturn nil, fmt.Errorf(\"Malformed 'contains(\\\"\\\")' selector\")\n\t\tdefault:\n\t\t\tif _, err := textToContain.WriteRune(r); err != nil {\n\t\t\t\treturn nil, err\n\t\t\t}\n\t\t}\n\t}\n}\n\n// Parse a :not(selector) selector\n// expects the input to be everything after the open parenthesis\n// e.g. for `not(div#id)` the argument would be `div#id)`\nfunc parseNotPseudo(cmd string) (PseudoClass, error) {\n\tif len(cmd) < 2 {\n\t\treturn nil, fmt.Errorf(\"malformed ':not' selector\")\n\t}\n\tendQuote, cmd := cmd[len(cmd)-1], cmd[:len(cmd)-1]\n\tselector, err := ParseSelector(cmd)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tif endQuote != ')' {\n\t\treturn nil, fmt.Errorf(\"unmatched '('\")\n\t}\n\treturn func(n *html.Node) bool {\n\t\treturn !selector.Match(n)\n\t}, nil\n}\n\n// Parse a :parent-of(selector) selector\n// expects the input to be everything after the open parenthesis\n// e.g. for `parent-of(div#id)` the argument would be `div#id)`\nfunc parseParentOfPseudo(cmd string) (PseudoClass, error) {\n\tif len(cmd) < 2 {\n\t\treturn nil, fmt.Errorf(\"malformed ':parent-of' selector\")\n\t}\n\tendQuote, cmd := cmd[len(cmd)-1], cmd[:len(cmd)-1]\n\tselector, err := ParseSelector(cmd)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tif endQuote != ')' {\n\t\treturn nil, fmt.Errorf(\"unmatched '('\")\n\t}\n\treturn func(n *html.Node) bool {\n\t\tfor c := n.FirstChild; c != nil; c = c.NextSibling {\n\t\t\tif c.Type == html.ElementNode && selector.Match(c) {\n\t\t\t\treturn true\n\t\t\t}\n\t\t}\n\t\treturn false\n\t}, nil\n}\n"
  },
  {
    "path": "tests/README.md",
    "content": "# Tests\n\nA simple set of tests to help maintain sanity.\n\nThese tests don't actually test functionality they only make sure pup behaves\nthe same after code changes.\n\n`cmds.txt` holds a list of commands to perform on `index.html`.\n\nThe output of each of these commands produces a specific sha1sum. The expected\nsha1sum of each command is in `expected_output.txt`.\n\nRunning the `test` file (just a bash script) will run the tests and diff the\noutput. If pup has changed at all since the last version, you'll see the sha1sums\nthat changed and the commands that produced that change. \n\nTo overwrite the current sha1sums, just run `python run.py > expected_output.txt`\n\n"
  },
  {
    "path": "tests/cmds.txt",
    "content": "#footer\n#footer li\n#footer li + a\n#footer li + a attr{title}\n#footer li > li\ntable li\ntable li:first-child\ntable li:first-of-type\ntable li:last-child\ntable li:last-of-type\ntable a[title=\"The Practice of Programming\"]\ntable a[title=\"The Practice of Programming\"] text{}\njson{}\ntext{}\n.after-portlet\n.after\n:empty\ntd:empty\n.navbox-list li:nth-child(1)\n.navbox-list li:nth-child(2)\n.navbox-list li:nth-child(3)\n.navbox-list li:nth-last-child(1)\n.navbox-list li:nth-last-child(2)\n.navbox-list li:nth-last-child(3)\n.navbox-list li:nth-child(n+1)\n.navbox-list li:nth-child(3n+1)\n.navbox-list li:nth-last-child(n+1)\n.navbox-list li:nth-last-child(3n+1)\n:only-child\n.navbox-list li:only-child\n.summary\n[class=summary]\n[class=\"summary\"]\n#toc\n#toc li + a\n#toc li + a text{}\n#toc li + a json{}\n#toc li + a + span\n#toc li + span\n#toc li > li\nli a:not([rel])\nlink, a\nlink ,a\nlink , a\nlink , a sup\nlink , a:parent-of(sup)\nlink , a:parent-of(sup) sup\nli --number\nli -n\n"
  },
  {
    "path": "tests/expected_output.txt",
    "content": "c00fef10d36c1166cb5ac886f9d25201b720e37e #footer\na7bb8dbfdd638bacad0aa9dc3674126d396b74e2 #footer li\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #footer li + a\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #footer li + a attr{title}\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #footer li > li\na92e50c09cd56970625ac3b74efbddb83b2731bb table li\n505c04a42e0084cd95560c233bd3a81b2c59352d table li:first-child\n505c04a42e0084cd95560c233bd3a81b2c59352d table li:first-of-type\n66950e746590d7f4e9cfe3d1adef42cd0addcf1d table li:last-child\n66950e746590d7f4e9cfe3d1adef42cd0addcf1d table li:last-of-type\n0a37d612cd4c67a42bd147b1edc5a1128456b017 table a[title=\"The Practice of Programming\"]\n0d3918d54f868f13110262ffbb88cbb0b083057d table a[title=\"The Practice of Programming\"] text{}\necb542a30fc75c71a0c6380692cbbc4266ccbce4 json{}\n95ef88ded9dab22ee3206cca47b9c3a376274bda text{}\ne4f7358fbb7bb1748a296fa2a7e815fa7de0a08b .after-portlet\nda39a3ee5e6b4b0d3255bfef95601890afd80709 .after\n5b3020ba03fb43f7cdbcb3924546532b6ec9bd71 :empty\n3406ca0f548d66a7351af5411ce945cf67a2f849 td:empty\n30fff0af0b1209f216d6e9124e7396c0adfa0758 .navbox-list li:nth-child(1)\na38e26949f047faab5ea7ba2acabff899349ce03 .navbox-list li:nth-child(2)\nd954831229a76b888e85149564727776e5a2b37a .navbox-list li:nth-child(3)\nd314e83b059bb876b0e5ee76aa92d54987961f9a .navbox-list li:nth-last-child(1)\n1f19496e239bca61a1109dbbb8b5e0ab3e302b50 .navbox-list li:nth-last-child(2)\n1ec9ebf14fc28c7d2b13e81241a6d2e1608589e8 .navbox-list li:nth-last-child(3)\n52e726f0993d2660f0fb3ea85156f6fbcc1cfeee .navbox-list li:nth-child(n+1)\n0b20c98650efa5df39d380fea8d5b43f3a08cb66 .navbox-list li:nth-child(3n+1)\n52e726f0993d2660f0fb3ea85156f6fbcc1cfeee .navbox-list li:nth-last-child(n+1)\n972973fe1e8f63e4481c8641d6169c638a528a6e .navbox-list li:nth-last-child(3n+1)\n6c45ee6bca361b8a9baee50a15f575fc6ac73adc :only-child\n44c99f6ad37b65dc0893cdcb1c60235d827ee73e .navbox-list li:only-child\n641037814e358487d1938fc080e08f72a3846ef8 .summary\n641037814e358487d1938fc080e08f72a3846ef8 [class=summary]\n641037814e358487d1938fc080e08f72a3846ef8 [class=\"summary\"]\n613bf65ac4042b6ee0a7a47f08732fdbe1b5b06b #toc\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li + a\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li + a text{}\n97d170e1550eee4afc0af065b78cda302a97674c #toc li + a json{}\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li + a + span\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li + span\nda39a3ee5e6b4b0d3255bfef95601890afd80709 #toc li > li\n87eee1189dd5296d6c010a1ad329fc53c6099d72 li a:not([rel])\n055f3c98e9160beb13f72f1009ad66b6252a9bba link, a\n055f3c98e9160beb13f72f1009ad66b6252a9bba link ,a\n055f3c98e9160beb13f72f1009ad66b6252a9bba link , a\n0d1f66765d1632c70f8608947890524e78459362 link , a sup\nb6a3d6cccd305fcc3e8bf2743c443743bdaaa02b link , a:parent-of(sup)\n0d1f66765d1632c70f8608947890524e78459362 link , a:parent-of(sup) sup\nda39a3ee5e6b4b0d3255bfef95601890afd80709 li --number\nda39a3ee5e6b4b0d3255bfef95601890afd80709 li -n\n"
  },
  {
    "path": "tests/index.html",
    "content": "\n\n\n\nGo (programming language) - Wikipedia, the free encyclopedia\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\t\t
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Go (programming language)
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From Wikipedia, the free encyclopedia
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Not to be confused with Go! (programming language), an agent-based language released in 2003.
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Go
\"Golang.png\"
Paradigm(s)compiled, concurrent, imperative, structured
Designed byRobert Griesemer
\nRob Pike
\nKen Thompson
DeveloperGoogle Inc.
Appeared in2009; 5 years ago (2009)
Stable releaseversion 1.3.3[1] / 1 October 2014; 39 days ago (2014-10-01)
Typing disciplinestrong, static, inferred, nominal
Major implementationsgc (8g, 6g, 5g), gccgo
Influenced byC, occam, Limbo, Modula, Newsqueak, Oberon, Pascal,[2] Python[citation needed]
Implementation languageC, Go, Asm
OSLinux, Mac OS X, FreeBSD, NetBSD, OpenBSD, MS Windows, Plan 9[3]
LicenseBSD-style[4] + Patent grant[5]
Filename extension(s).go
Websitegolang.org
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Go, also commonly referred to as golang, is a programming language initially developed at Google[6] in 2007 by Robert Griesemer, Rob Pike, and Ken Thompson.[2] It is a statically-typed language with syntax loosely derived from that of C, adding garbage collection, type safety, some dynamic-typing capabilities, additional built-in types such as variable-length arrays and key-value maps, and a large standard library.
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The language was announced in November 2009 and is now used in some of Google's production systems.[7] Go's \"gc\" compiler targets the Linux, Mac OS X, FreeBSD, NetBSD, OpenBSD, Plan 9, and Microsoft Windows operating systems and the i386, amd64, and ARM processor architectures.[8] A second compiler, gccgo, is a GCC frontend.[9][10]
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History[edit]
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Ken Thompson states that, initially, Go was purely an experimental project. Referring to himself along with the other original authors of Go, he states:[11]
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When the three of us [Thompson, Rob Pike, and Robert Griesemer] got started, it was pure research. The three of us got together and decided that we hated C++. [laughter] ... [Returning to Go,] we started off with the idea that all three of us had to be talked into every feature in the language, so there was no extraneous garbage put into the language for any reason.
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The history of the language before its first release, back to 2007, is covered in the language's FAQ.[12]
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Language design[edit]
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Go is recognizably in the tradition of C, but makes many changes aimed at conciseness, simplicity, and safety. The following is a brief overview of the features which define Go (for more information see the language specification):
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Syntax[edit]
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Go's syntax includes changes from C aimed at keeping code concise and readable. The programmer needn't specify the types of expressions, allowing just i := 3 or s := \"some words\" to replace C's int i = 3; or char* s = \"some words\";. Semicolons at the end of lines aren't required. Functions may return multiple, named values, and returning a result, err pair is the conventional way a function indicates an error to its caller in Go.[a] Go adds literal syntaxes for initializing struct parameters by name, and for initializing maps and slices. As an alternative to C's three-statement for loop, Go's range expressions allow concise iteration over arrays, slices, strings, and maps.
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Types[edit]
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Go adds some basic types not present in C for safety and convenience:
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  • Slices (written []type) point into an array of objects in memory, storing a pointer to the start of the slice, a length, and a capacity specifying when new memory needs to be allocated to expand the array. Slice contents are passed by reference, and their contents are always mutable.
    • \n
  • Go's immutable string type typically holds UTF-8 text (though it can hold arbitrary bytes as well).
    • \n
  • map[keytype]valtype provides a hashtable.
    • \n
  • Go also adds channel types, which support concurrency and are discussed below, and interfaces, which replace virtual inheritance and are discussed in Interface system section.
    • \n
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Structurally, Go's type system has a few differences from C and most C derivatives. Unlike C typedefs, Go's named types are not aliases for each other, and rules limit when different types can be assigned to each other without explicit conversion.[19] Unlike in C, conversions between number types are explicit; to ensure that doesn't create verbose conversion-heavy code, numeric constants in Go represent abstract, untyped numbers.[20] Finally, in place of non-virtual inheritance, Go has a feature called type embedding in which one object can contain others and pick up their methods.
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Package system[edit]
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In Go's package system, each package has a path (e.g., \"compress/bzip2\" or \"code.google.com/p/go.net/html\") and a name (e.g., bzip2 or html). References to other packages' definitions must always be prefixed with the other package's name, and only the capitalized names from other modules are accessible: io.Reader is public but bzip2.reader is not.[21] The go get command can retrieve packages stored in a remote repository such as Github or Google Code, and package paths often look like partial URLs for compatibility.[22]
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Concurrency: goroutines, channels, and select[edit]
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Go provides facilities for writing concurrent programs that share state by communicating.[23][24][25] Concurrency refers not only to multithreading and CPU parallelism, which Go supports, but also to asynchrony: letting slow operations like a database or network-read run while the program does other work, as is common in event-based servers.[26]
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Go's concurrency-related syntax and types include:
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    \n
  • The go statement, go func(), starts a function in a new light-weight process, or goroutine
    • \n
  • Channel types, chan type, provide a type-safe, synchronized, optionally buffered channels between goroutines, and are useful mostly with two other facilities:\n
      \n
    • The send statement, ch <- x sends x over ch
      • \n
    • The receive operator, <- ch receives a value from ch
      • \n
    • Both operations block until the other goroutine is ready to communicate
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    \n
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  • The select statement uses a switch-like syntax to wait for communication on any of a set of channels[27]
    • \n
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From these tools one can build concurrent constructs like worker pools, pipelines (in which, say, a file is decompressed and parsed as it downloads), background calls with timeout, \"fan-out\" parallel calls to a set of services, and others.[28] Channels have also found uses further from the usual notion of interprocess communication, like serving as a concurrency-safe list of recycled buffers,[29] implementing coroutines (which helped inspire the name goroutine),[30] and implementing iterators.[31]
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While the communicating-processes model is favored in Go, it isn't the only one: memory can be shared across goroutines (see below), and the standard sync module provides locks and other primitives.[32]
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Race condition safety[edit]
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There are no restrictions on how goroutines access shared data, making race conditions possible. Specifically, unless a program explicitly synchronizes via channels or other means, writes from one goroutine might be partly, entirely, or not at all visible to another, often with no guarantees about ordering of writes.[33] Furthermore, Go's internal data structures like interface values, slice headers, and string headers are not immune to race conditions, so type and memory safety can be violated in multithreaded programs that modify shared instances of those types without synchronization.[34][35]
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Idiomatic Go minimizes sharing of data (and thus potential race conditions) by communicating over channels, and a race-condition tester is included in the standard distribution to help catch unsafe behavior. Still, it is important to realize that while Go provides building blocks that can be used to write correct, comprehensible concurrent code, arbitrary code isn't guaranteed to be safe.
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Some concurrency-related structural conventions of Go (channels and alternative channel inputs) are derived from Tony Hoare's communicating sequential processes model. Unlike previous concurrent programming languages such as occam or Limbo (a language on which Go co-designer Rob Pike worked[36]), Go does not provide any built-in notion of safe or verifiable concurrency.[33]
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Interface system[edit]
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In place of virtual inheritance, Go uses interfaces. An interface declaration is nothing but a list of required methods: for example, implementing io.Reader requires a Read method that takes a []byte and returns a count of bytes read and any error.[37] Code calling Read needn't know whether it's reading from an HTTP connection, a file, an in-memory buffer, or any other source.
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Go's standard library defines interfaces for a number of concepts: input sources and output sinks, sortable collections, objects printable as strings, cryptographic hashes, and so on.
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Go types don't declare which interfaces they implement: having the required methods is implementing the interface. In formal language, Go's interface system provides structural rather than nominal typing.
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The example below uses the io.Reader and io.Writer interfaces to test Go's implementation of SHA-256 on a standard test input, 1,000,000 repeats of the character \"a\". RepeatByte implements an io.Reader yielding an infinite stream of repeats of a byte, similar to Unix /dev/zero. The main() function uses RepeatByte to stream a million repeats of \"a\" into the hash function, then prints the result, which matches the expected value published online.[38] Even though both reader and writer interfaces are needed to make this work, the code needn't mention either; the compiler infers what types implement what interfaces:
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\npackage main\n \nimport (\n    \"fmt\"\n    \"io\"\n    \"crypto/sha256\"\n)\n \ntype RepeatByte byte\n \nfunc (r RepeatByte) Read(p []byte) (n int, err error) {\n    for i := range p {\n        p[i] = byte(r)\n    }\n    return len(p), nil\n}\n \nfunc main() {\n    testStream := RepeatByte('a')\n    hasher := sha256.New()\n    io.CopyN(hasher, testStream, 1000000)\n    fmt.Printf(\"%x\", hasher.Sum(nil))\n}\n
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(Run or edit this example online.)
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Also note type RepeatByte is defined as a byte, not a struct. Named types in Go needn't be structs, and any named type can have methods defined, satisfy interfaces, and act, for practical purposes, as objects; the standard library, for example, stores IP addresses in byte slices.[39]
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Besides calling methods via interfaces, Go allows converting interface values to other types with a run-time type check. The language constructs to do so are the type assertion,[40] which checks against a single potential type, and the type switch,[41] which checks against multiple types.
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interface{}, the empty interface, is an important corner case because it can refer to an item of any concrete type, including primitive types like string. Code using the empty interface can't simply call methods (or built-in operators) on the referred-to object, but it can store the interface{} value, try to convert it to a more useful type via a type assertion or type switch, or inspect it with Go's reflect package.[42] Because interface{} can refer to any value, it's a limited way to escape the restrictions of static typing, like void* in C but with additional run-time type checks.
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Interface values are stored in memory as a pointer to data and a second pointer to run-time type information.[43] Like other pointers in Go, interface values are nil if uninitialized.[44] Unlike in environments like Java's virtual machine, there is no object header; the run-time type information is only attached to interface values. So, the system imposes no per-object memory overhead for objects not accessed via interface, similar to C structs or C# ValueTypes.
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Go does not have interface inheritance, but one interface type can embed another; then the embedding interface requires all of the methods required by the embedded interface.[45]
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Omissions[edit]
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Go deliberately omits certain features common in other languages, including generic programming, assertions, pointer arithmetic, and inheritance. After initially omitting exceptions, the language added the panic/recover mechanism, but it is only meant for rare circumstances.[46][47][48]
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The Go authors express an openness to generic programming, explicitly argue against assertions and pointer arithmetic, while defending the choice to omit type inheritance as giving a more useful language, encouraging heavy use of interfaces instead.[2]
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Conventions and code style[edit]
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The Go authors and community put substantial effort into molding the style and design of Go programs:
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  • Indentation, spacing, and other surface-level details of code are automatically standardized by the go fmt tool. go vet and golint do additional checking automatically.
    • \n
  • Tools and libraries distributed with Go suggest standard approaches to things like API documentation (godoc[49]), testing (go test), building (go build), package management (go get), and so on.
    • \n
  • Syntax rules require things that are optional in other languages, for example by banning cyclic dependencies, unused variables or imports, and implicit type conversions.
    • \n
  • The omission of certain features (for example, functional-programming shortcuts like map and C++-style try/finally blocks) tends to encourage a particular explicit, concrete, and imperative programming style.
    • \n
  • Core developers write extensively about Go idioms, style, and philosophy, in the Effective Go document and code review comments reference, presentations, blog posts, and public mailing list messages.
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When adapting to the Go ecosystem after working in other languages, differences in style and approach can be as important as low-level language and library differences.
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Language tools[edit]
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Go includes the same sort of debugging, testing, and code-vetting tools as many language distributions. The Go distribution includes go vet, which analyzes code searching for common stylistic problems and mistakes. A profiler, unit testing tool, gdb debugging support, and a race condition tester are also in the distribution. The Go distribution includes its own build system, which requires only information in the Go files themselves, no separate build files.
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There is an ecosystem of third-party tools that add to the standard distribution, such as gocode, which enables code autocompletion in many text editors, goimports (by a Go team member), which automatically adds/removes package imports as needed, errcheck, which detects code that might unintentionally ignore errors, and more. Plugins exist to add language support in widely used text editors, and at least one IDE, LiteIDE, targets Go in particular.
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Examples[edit]
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Hello world[edit]
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Here is a Hello world program in Go:
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\npackage main\n \nimport \"fmt\"\n \nfunc main() {\n    fmt.Println(\"Hello, World\")\n}\n
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(Run or edit this example online.)
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Echo[edit]
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This imitates the Unix echo command in Go:[50]
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\npackage main\n \nimport (\n    \"flag\"\n    \"fmt\"\n    \"strings\"\n)\n \nfunc main() {\n    var omitNewline bool\n    flag.BoolVar(&omitNewline, \"n\", false, \"don't print final newline\")\n    flag.Parse() // Scans the arg list and sets up flags.\n \n    str := strings.Join(flag.Args(), \" \")\n    if omitNewline {\n        fmt.Print(str)\n    } else {\n        fmt.Println(str)\n    }\n}\n
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File Read[edit]
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\n// Reading and writing files are basic tasks needed for\n// many Go programs. First we'll look at some examples of\n// reading files.\n \npackage main\n \nimport (\n    \"bufio\"\n    \"fmt\"\n    \"io\"\n    \"io/ioutil\"\n    \"os\"\n)\n \n// Reading files requires checking most calls for errors.\n// This helper will streamline our error checks below.\nfunc check(e error) {\n    if e != nil {\n        panic(e)\n    }\n}\n \nfunc main() {\n \n    // Perhaps the most basic file reading task is\n    // slurping a file's entire contents into memory.\n    dat, err := ioutil.ReadFile(\"/tmp/dat\")\n    check(err)\n    fmt.Print(string(dat))\n \n    // You'll often want more control over how and what\n    // parts of a file are read. For these tasks, start\n    // by `Open`ing a file to obtain an `os.File` value.\n    f, err := os.Open(\"/tmp/dat\")\n    check(err)\n \n    // Read some bytes from the beginning of the file.\n    // Allow up to 5 to be read but also note how many\n    // actually were read.\n    b1 := make([]byte, 5)\n    n1, err := f.Read(b1)\n    check(err)\n    fmt.Printf(\"%d bytes: %s\\n\", n1, string(b1))\n \n    // You can also `Seek` to a known location in the file\n    // and `Read` from there.\n    o2, err := f.Seek(6, 0)\n    check(err)\n    b2 := make([]byte, 2)\n    n2, err := f.Read(b2)\n    check(err)\n    fmt.Printf(\"%d bytes @ %d: %s\\n\", n2, o2, string(b2))\n \n    // The `io` package provides some functions that may\n    // be helpful for file reading. For example, reads\n    // like the ones above can be more robustly\n    // implemented with `ReadAtLeast`.\n    o3, err := f.Seek(6, 0)\n    check(err)\n    b3 := make([]byte, 2)\n    n3, err := io.ReadAtLeast(f, b3, 2)\n    check(err)\n    fmt.Printf(\"%d bytes @ %d: %s\\n\", n3, o3, string(b3))\n \n    // There is no built-in rewind, but `Seek(0, 0)`\n    // accomplishes this.\n    _, err = f.Seek(0, 0)\n    check(err)\n \n    // The `bufio` package implements a buffered\n    // reader that may be useful both for its efficiency\n    // with many small reads and because of the additional\n    // reading methods it provides.\n    r4 := bufio.NewReader(f)\n    b4, err := r4.Peek(5)\n    check(err)\n    fmt.Printf(\"5 bytes: %s\\n\", string(b4))\n \n    // Close the file when you're done (usually this would\n    // be scheduled immediately after `Open`ing with\n    // `defer`).\n    f.Close()\n \n}\n
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[51][52]
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Notable users[edit]
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Some notable open-source applications in Go include:
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Other companies and sites using Go (generally together with other languages, not exclusively) include:[53][54]
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Libraries[edit]
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Go's open-source libraries include:
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  • Go's standard library, which covers a lot of fundamental functionality:\n
      \n
    • Algorithms: compression, cryptography, sorting, math, indexing, and text and string manipulation.
      • \n
    • External interfaces: I/O, network clients and servers, parsing and writing common formats, running system calls, and interacting with C code.
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    • Development tools: reflection, runtime control, debugging, profiling, unit testing, synchronization, and parsing Go.
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  • Third-party libraries with more specialized tools:\n\n
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Some sites help index the libraries outside the Go distribution:
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Community and conferences[edit]
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  • Gopher Academy, Gopher Academy is a group of developers working to educate and promote the golang community.
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  • Golangprojects.com, lists programming jobs and projects where companies are looking for people that know Go
    • \n
  • GopherCon The first Go conference. Denver, Colorado, USA April 24-26 2014
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  • dotGo European conference. Paris, France October 10 2014
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  • GopherConIndia The first Go conference in India. Bangalore Feb. 19-21 2015
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Reception[edit]
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Go's initial release led to much discussion.
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Michele Simionato wrote in an article for artima.com:[62]
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Here I just wanted to point out the design choices about interfaces and inheritance. Such ideas are not new and it is a shame that no popular language has followed such particular route in the design space. I hope Go will become popular; if not, I hope such ideas will finally enter in a popular language, we are already 10 or 20 years too late :-(
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Dave Astels at Engine Yard wrote:[63]
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Go is extremely easy to dive into. There are a minimal number of fundamental language concepts and the syntax is clean and designed to be clear and unambiguous. Go is still experimental and still a little rough around the edges.
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Ars Technica interviewed Rob Pike, one of the authors of Go, and asked why a new language was needed. He replied that:[64]
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It wasn't enough to just add features to existing programming languages, because sometimes you can get more in the long run by taking things away. They wanted to start from scratch and rethink everything. ... [But they did not want] to deviate too much from what developers already knew because they wanted to avoid alienating Go's target audience.
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Go was named Programming Language of the Year by the TIOBE Programming Community Index in its first year, 2009, for having a larger 12-month increase in popularity (in only 2 months, after its introduction in November) than any other language that year, and reached 13th place by January 2010,[65] surpassing established languages like Pascal. As of August 2014[update], its ranking had dropped to 38th in the index, placing it lower than COBOL and Fortran.[66] Go is already in commercial use by several large organizations.[67]
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Regarding Go, Bruce Eckel has stated:[68]
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The complexity of C++ (even more complexity has been added in the new C++), and the resulting impact on productivity, is no longer justified. All the hoops that the C++ programmer had to jump through in order to use a C-compatible language make no sense anymore -- they're just a waste of time and effort. Now, Go makes much more sense for the class of problems that C++ was originally intended to solve.
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Mascot[edit]
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Go's mascot is a gopher designed by Renée French, who also designed Glenda, the Plan 9 Bunny. The logo and mascot are licensed under Creative Commons Attribution 3.0 license.[69]
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Naming dispute[edit]
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On the day of the general release of the language, Francis McCabe, developer of the Go! programming language (note the exclamation point), requested a name change of Google's language to prevent confusion with his language.[70] The issue was closed by a Google developer on 12 October 2010 with the custom status \"Unfortunate\" and with the following comment: \"there are many computing products and services named Go. In the 11 months since our release, there has been minimal confusion of the two languages.\"[71]
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See also[edit]
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\"PortalFree software portal
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Notes[edit]
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    \n
  1. ^ Usually, exactly one of the result and error values has a value other than the type's zero value; sometimes both do, as when a read or write can only be partially completed, and sometimes neither, as when a read returns 0 bytes. See Semipredicate problem: Multivalued return.
    2. \n
\n
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References[edit]
\n
This article incorporates material from the official Go tutorial, which is licensed under the Creative Commons Attribution 3.0 license.
\n
\n
    \n
  1. ^ \"Go 1.3.3 is released\". golang-nuts group. 1 October 2014. Retrieved 5 November 2014. 
    2. \n
  2. ^ a b c \"Language Design FAQ\". golang.org. 16 January 2010. Retrieved 27 February 2010. 
    3. \n
  3. ^ \"Go Porting Efforts\". Go Language Resources. cat-v. 12 January 2010. Retrieved 18 January 2010. 
    4. \n
  4. ^ \"Text file LICENSE\". The Go Programming Language. Google. Retrieved 5 October 2012. 
    5. \n
  5. ^ \"Additional IP Rights Grant\". The Go Programming Language. Google. Retrieved 5 October 2012. 
    6. \n
  6. ^ Kincaid, Jason (10 November 2009). \"Google’s Go: A New Programming Language That’s Python Meets C++\". TechCrunch. Retrieved 18 January 2010. 
    7. \n
  7. ^ \"Go FAQ: Is Google using Go internally?\". Retrieved 9 March 2013. 
    8. \n
  8. ^ \"Installing Go\". golang.org. The Go Authors. 11 June 2010. Retrieved 11 June 2010. 
    9. \n
  9. ^ \"FAQ: Implementation\". golang.org. 16 January 2010. Retrieved 18 January 2010. 
    10. \n
  10. ^ \"Installing GCC: Configuration\". Retrieved 3 December 2011. \"Ada, Go and Objective-C++ are not default languages\" 
    11. \n
  11. ^ Andrew Binstock (18 May 2011). \"Dr. Dobb's: Interview with Ken Thompson\". Retrieved 7 February 2014. 
    12. \n
  12. ^ \"Frequently Asked Questions (FAQ) - The Go Programming Language\". Golang.org. Retrieved 2014-03-27. 
    13. \n
  13. ^ Pike, Rob. \"The Go Programming Language\". YouTube. Retrieved 1 Jul 2011. 
    14. \n
  14. ^ Rob Pike (10 November 2009). The Go Programming Language (flv) (Tech talk). Google. Event occurs at 8:53. 
    15. \n
  15. ^ Download and install packages and dependencies - go - The Go Programming Language; see godoc.org for addresses and documentation of some packages
    16. \n
  16. ^ godoc.org and, for the standard library, golang.org/pkg
    17. \n
  17. ^ Rob Pike, on The Changelog podcast
    18. \n
  18. ^ Rob Pike, Less is exponentially more
    19. \n
  19. ^ Assignability - the Go Language Specification
    20. \n
  20. ^ Constants - the Go Language Specification
    21. \n
  21. ^ \"A Tutorial for the Go Programming Language\". The Go Programming Language. Google. Retrieved 10 March 2013. \"In Go the rule about visibility of information is simple: if a name (of a top-level type, function, method, constant or variable, or of a structure field or method) is capitalized, users of the package may see it. Otherwise, the name and hence the thing being named is visible only inside the package in which it is declared.\" 
    22. \n
  22. ^ Download and install packages and dependencies - go - The Go Programming Language
    23. \n
  23. ^ Share by communicating - Effective Go
    24. \n
  24. ^ Andrew Gerrand, Share memory by communicating
    25. \n
  25. ^ Andrew Gerrand, Codewalk: Share memory by communicating
    26. \n
  26. ^ For more discussion, see Rob Pike, Concurrency is not Parallelism
    27. \n
  27. ^ The Go Programming Language Specification. This deliberately glosses over some details in the spec: close, channel range expressions, the two-argument form of the receive operator, unidrectional channel types, and so on.
    28. \n
  28. ^ Concurrency patterns in Go
    29. \n
  29. ^ John Graham-Cumming, Recycling Memory Buffers in Go
    30. \n
  30. ^ tree.go
    31. \n
  31. ^ Ewen Cheslack-Postava, Iterators in Go
    32. \n
  32. ^ sync - The Go Programming Language
    33. \n
  33. ^ a b \"The Go Memory Model\". Google. Retrieved 5 January 2011. 
    34. \n
  34. ^ Russ Cox, Off to the Races
    35. \n
  35. ^ Rob Pike (October 25, 2012). \"Go at Google: Language Design in the Service of Software Engineering\". Google, Inc.  \"There is one important caveat: Go is not purely memory safe in the presence of concurrency.\"
    36. \n
  36. ^ Brian W. Kernighan, A Descent Into Limbo
    37. \n
  37. ^ Reader - io - The Go Programming Language
    38. \n
  38. ^ SHA-256 test vectors, set 1, vector #8
    39. \n
  39. ^ src/pkg/net/ip.go
    40. \n
  40. ^ Type Assertions - The Go Language Specification
    41. \n
  41. ^ Type switches - The Go Language Specification
    42. \n
  42. ^ reflect.ValueOf(i interface{}) converts an interface{} to a reflect.Value that can be further inspected
    43. \n
  43. ^ \"Go Data Structures: Interfaces\". Retrieved 15 November 2012. 
    44. \n
  44. ^ Interface types - The Go Programming Language Specification
    45. \n
  45. ^ \"Effective Go — Interfaces and methods & Embedding\". Google. Retrieved 28 November 2011. 
    46. \n
  46. ^ Panic And Recover, Go wiki
    47. \n
  47. ^ Release notes, 30 March 2010
    48. \n
  48. ^ \"Proposal for an exception-like mechanism\". golang-nuts. 25 March 2010. Retrieved 25 March 2010. 
    49. \n
  49. ^ Commentary - Effective Go
    50. \n
  50. ^ \"A Tutorial for the Go Programming Language\". golang.org. 16 January 2010. Retrieved 18 January 2010. 
    51. \n
  51. ^ https://gobyexample.com/reading-files.  Missing or empty |title= (help)
    52. \n
  52. ^ http://golang.org/pkg/os/.  Missing or empty |title= (help)
    53. \n
  53. ^ Erik Unger, The Case For Go
    54. \n
  54. ^ Andrew Gerrand, Four years of Go, The Go Blog
    55. \n
  55. ^ dl.google.com: Powered by Go
    56. \n
  56. ^ Matt Welsh, Rewriting a Large Production System in Go
    57. \n
  57. ^ David Symonds, High Performance Apps on Google App Engine
    58. \n
  58. ^ Patrick Lee, Open Sourcing Our Go Libraries, 7 July 2014.
    59. \n
  59. ^ John Graham-Cumming, Go at CloudFlare
    60. \n
  60. ^ John Graham-Cumming, What we've been doing with Go
    61. \n
  61. ^ Peter Bourgon, Go at SoundCloud
    62. \n
  62. ^ Simionato, Michele (15 November 2009). \"Interfaces vs Inheritance (or, watch out for Go!)\". artima. Retrieved 15 November 2009. 
    63. \n
  63. ^ Astels, Dave (9 November 2009). \"Ready, Set, Go!\". engineyard. Retrieved 9 November 2009. 
    64. \n
  64. ^ Paul, Ryan (10 November 2009). \"Go: new open source programming language from Google\". Ars Technica. Retrieved 13 November 2009. 
    65. \n
  65. ^ \"Google's Go Wins Programming Language Of The Year Award\". jaxenter. Retrieved 5 December 2012.  |first1= missing |last1= in Authors list (help)
    66. \n
  66. ^ \"TIOBE Programming Community Index for August 2014\". TIOBE Software. August 2014. Retrieved 22 August 2014. 
    67. \n
  67. ^ \"Organizations Using Go\". 
    68. \n
  68. ^ Bruce Eckel (27 August 2011). \"Calling Go from Python via JSON-RPC\". Retrieved 29 August 2011. 
    69. \n
  69. ^ \"FAQ — The Go Programming Language\". Golang.org. Retrieved 2013-06-25. 
    70. \n
  70. ^ Claburn, Thomas (11 November 2009). \"Google 'Go' Name Brings Accusations Of Evil'\". InformationWeek. Retrieved 18 January 2010. 
    71. \n
  71. ^ \"Issue 9 - go — I have already used the name for *MY* programming language\". Google Code. Google Inc. Retrieved 12 October 2010. 
    72. \n
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  },
  {
    "path": "tests/run.py",
    "content": "#!/usr/bin/env python\n\nfrom __future__ import print_function\nfrom hashlib import sha1\nfrom subprocess import Popen, PIPE, STDOUT\n\ndata = open(\"index.html\", \"r\").read()\n\nfor line in open(\"cmds.txt\", \"r\"):\n    line = line.strip()\n    p = Popen(['pup', line], stdout=PIPE, stdin=PIPE, stderr=PIPE)\n    h = sha1()\n    h.update(p.communicate(input=data)[0])\n    print(\"%s %s\" % (h.hexdigest(), line))\n"
  },
  {
    "path": "tests/test",
    "content": "#!/bin/bash\n\npython run.py > test_results.txt\ndiff expected_output.txt test_results.txt\n"
  }
]