gobyexample/tool/generate.go
Mark McGranaghan 905d6d97c3 just use go/run
2012-09-29 14:17:53 -07:00

145 lines
4.2 KiB
Go

// ## golit
// **golit** generates literate-programming style HTML
// documentation from a Go source files.
package main
import (
"fmt"
"io/ioutil"
"os"
"os/exec"
"regexp"
"strings"
)
// Recognize doc lines, extract their comment prefixes.
var docsPat = regexp.MustCompile("^\\s*\\/\\/\\s")
// Recognize title prefixes, for titling web page.
var titlePat = regexp.MustCompile("^\\/\\/\\s##\\s")
// Abort on non-nil errors.
func check(err error) {
if err != nil {
panic(err)
}
}
// We'll implement Markdown rendering and Pygments syntax
// highlighting by piping data through external programs.
// This is a general helper for handling both cases.
func pipedCmd(binary string, argv []string, input string) string {
cmd := exec.Command(binary, argv...)
in, err := cmd.StdinPipe()
check(err)
out, err := cmd.StdoutPipe()
check(err)
err = cmd.Start()
check(err)
in.Write([]byte(input))
check(err)
err = in.Close()
check(err)
bytes, err := ioutil.ReadAll(out)
check(err)
err = cmd.Wait()
check(err)
return string(bytes)
}
// We'll break the code into {docs, code} pairs,
// and then render those text segments before
// including them in the HTML doc.
type segment struct {
docs, code, docsRendered, codeRendered string
}
func main() {
// Accept exactly 1 argument - the input filename, less the .go extension.
if len(os.Args) != 2 {
fmt.Fprintln(os.Stderr, "Usage: go run tool/generate.go input > output.html")
os.Exit(1)
}
// Ensure that we have `markdown` and `pygmentize`,
// binaries, remember their paths.
markdownPath, err := exec.LookPath("markdown")
check(err)
pygmentizePath, err := exec.LookPath("pygmentize")
check(err)
// Read the source file in, split into lines.
sourceBytes, err := ioutil.ReadFile(os.Args[1]+".go")
check(err)
lines := strings.Split(string(sourceBytes), "\n")
// Group lines into docs/code segments.
// Special case the header to go in its own segment.
segments := []*segment{}
segments = append(segments, &segment{code: "", docs: docsPat.ReplaceAllString(lines[0], "")})
segments = append(segments, &segment{code: "", docs: ""})
lastLine := ""
for _, line := range lines[2:] {
head := segments[len(segments)-1]
// Doc line - trim off the comment markers.
if (line == "" && lastLine == "docs") || docsPat.MatchString(line) {
trimLine := docsPat.ReplaceAllString(line, "")
if !(lastLine == "code" && head.docs != "") {
head.docs = head.docs + "\n" + trimLine
} else {
segments = append(segments, &segment{docs: trimLine, code: ""})
}
lastLine = "docs"
// Code line - preserve all whitespace.
} else {
if !(lastLine == "docs" && head.code != "") {
head.code = head.code + "\n" + line
} else {
segments = append(segments, &segment{docs: "", code: line})
}
lastLine = "code"
}
}
// Render docs via `markdown` and code via
// `pygmentize` in each segment.
for _, seg := range segments {
seg.docsRendered = pipedCmd(markdownPath, []string{}, seg.docs)
seg.codeRendered = pipedCmd(pygmentizePath, []string{"-l", "go", "-f", "html"}, seg.code+" ")
}
// Print HTML header.
fmt.Printf(`
<!DOCTYPE html>
<html>
<head>
<meta http-eqiv="content-type" content="text/html;charset=utf-8">
<title>%s</title>
<link rel=stylesheet href="http://jashkenas.github.com/docco/resources/docco.css">
</head>
<body>
<div id="container">
<div id="background"></div>
<table cellspacing="0" cellpadding="0">
<thead>
<tr><td class=docs></td><td class=code></td></tr>
</thead>
<tbody>`, titlePat.ReplaceAllString(lines[0], ""))
// Print HTML docs/code segments.
for _, seg := range segments {
fmt.Printf("<tr><td class=docs>%s</td><td class=code>%s</td></tr>\n", seg.docsRendered, seg.codeRendered)
}
// Print HTML footer.
fmt.Print(`
</tbody>
</table>
</div>
</body>
</html>
`)
}