// Generate an HTML file from the book source. Derived from golit.
package main
import (
"fmt"
"io/ioutil"
"os"
"os/exec"
"regexp"
"strings"
)
func check(err error) {
if err != nil {
panic(err)
}
}
func whichRenderers() (string, string) {
markdownPath, err := exec.LookPath("markdown")
check(err)
pygmentizePath, err := exec.LookPath("pygmentize")
check(err)
return markdownPath, pygmentizePath
}
func render(bin string, arg []string, src string) string {
cmd := exec.Command(bin, arg...)
in, _ := cmd.StdinPipe()
out, _ := cmd.StdoutPipe()
cmd.Start()
in.Write([]byte(src))
in.Close()
bytes, _ := ioutil.ReadAll(out)
err := cmd.Wait()
check(err)
return string(bytes)
}
func readLines(path string) []string {
srcBytes, err := ioutil.ReadFile(path)
check(err)
return strings.Split(string(srcBytes), "\n")
}
func whichLexer(path string) string {
if strings.HasSuffix(path, ".go") {
return "go"
} else if strings.HasSuffix(path, ".sh") {
return "console"
}
panic("No lexer for " + path)
return ""
}
var docsPat = regexp.MustCompile("^\\s*(\\/\\/|#)\\s")
var headerPat = regexp.MustCompile("^\\s*(\\/\\/|#)\\s#+\\s")
type seg struct {
docs, code, docsRendered, codeRendered string
}
func main() {
if len(os.Args) <= 1 {
fmt.Fprintln(os.Stderr, "usage: tool/generate *.{go,sh} > output.html")
os.Exit(1)
}
markdownPath, pygmentizePath := whichRenderers()
fmt.Print(`
Go by Example
`)
for _, sourcePath := range os.Args[1:] {
lexer := whichLexer(sourcePath)
lines := readLines(sourcePath)
segs := []*seg{}
segs = append(segs, &seg{code: "", docs: ""})
lastSeen := ""
for _, line := range lines {
headerMatch := headerPat.MatchString(line)
docsMatch := docsPat.MatchString(line)
emptyMatch := line == ""
lastSeg := segs[len(segs)-1]
lastHeader := lastSeen == "header"
lastDocs := lastSeen == "docs"
newHeader := (lastSeen != "header") && lastSeg.docs != ""
newDocs := (lastSeen != "docs") && lastSeg.docs != ""
newCode := (lastSeen != "code") && lastSeg.code != ""
if headerMatch || (emptyMatch && lastHeader) {
trimmed := docsPat.ReplaceAllString(line, "")
if newHeader {
newSeg := seg{docs: trimmed, code: ""}
segs = append(segs, &newSeg)
} else {
lastSeg.docs = lastSeg.docs + "\n" + trimmed
}
lastSeen = "header"
} else if docsMatch || (emptyMatch && lastDocs) {
trimmed := docsPat.ReplaceAllString(line, "")
if newDocs {
newSeg := seg{docs: trimmed, code: ""}
segs = append(segs, &newSeg)
} else {
lastSeg.docs = lastSeg.docs + "\n" + trimmed
}
lastSeen = "docs"
} else {
if newCode {
newSeg := seg{docs: "", code: line}
segs = append(segs, &newSeg)
} else {
lastSeg.code = lastSeg.code + "\n" + line
}
lastSeen = "code"
}
}
segs = append(segs, &seg{code: "", docs: ""})
for _, seg := range segs {
if seg.docs != "" {
seg.docsRendered = render(markdownPath, []string{}, seg.docs)
}
if seg.code != "" {
seg.codeRendered = render(pygmentizePath, []string{"-l", lexer, "-f", "html"}, seg.code)
}
}
for _, seg := range segs {
codeClasses := "code"
if seg.code == "" {
codeClasses = codeClasses + " empty"
}
fmt.Printf(
`
| %s |
%s |
`, seg.docsRendered, codeClasses, seg.codeRendered)
}
}
fmt.Print(`
`)
}