Line Filters+ | ///
+
+ |
Generate literate-programming style HTML +documentation form 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")
+
+ |
Abort on non-nil errors. + | func check(err error) {
+ if err != nil {
+ panic(err)
+ }
+}
+
+ |
For docs and code rendering: pipe source data +through binary at path with given argv, return +the output. + | func pipedCmd(path string, argv []string, source string) string {
+ cmd := exec.Command(path, argv...)
+ in, err := cmd.StdinPipe()
+ check(err)
+ out, err := cmd.StdoutPipe()
+ check(err)
+ err = cmd.Start()
+ check(err)
+ in.Write([]byte(source))
+ 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. + | if len(os.Args) != 2 {
+ fmt.Fprintln(os.Stderr, "Usage: tool/generate input.go > output.html")
+ os.Exit(1)
+ }
+
+ |
Ensure that we have | 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])
+ check(err)
+ lines := strings.Split(string(sourceBytes), "\n")
+
+ |
Group lines into docs/code segments. + | segments := []*segment{}
+ segments = append(segments, &segment{code: "", docs: ""})
+ lastLine := ""
+ for _, line := range lines {
+ 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 | 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.Print(`
+<!DOCTYPE html>
+<html>
+ <head>
+ <meta http-eqiv="content-type" content="text/html;charset=utf-8">
+ <title>Page Title</title>
+ <link rel=stylesheet href="book.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>`)
+
+ |
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>
+`)
+}
+
+ |