diff --git a/tool/generate.go b/tool/generate.go
index 3004615..44de80e 100644
--- a/tool/generate.go
+++ b/tool/generate.go
@@ -3,12 +3,16 @@
 package main
 
 import (
+    "fmt"
+    "io/ioutil"
     "os"
     "os/exec"
-    "io/ioutil"
-    "fmt"
+    "regexp"
+    "strings"
 )
 
+var docsPat = regexp.MustCompile("^\\s*\\/\\/\\s")
+
 // Just be sure to blow up on non-nil errors.
 func check(err error) {
     if err != nil {
@@ -16,6 +20,8 @@ func check(err error) {
     }
 }
 
+// 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()
@@ -35,6 +41,10 @@ func pipedCmd(path string, argv []string, source string) string {
     return string(bytes)
 }
 
+type segment struct {
+    docs, code string
+}
+
 func main() {
     // Accept exactly 1 argument - the input filename.
     if len(os.Args) != 2 {
@@ -44,16 +54,45 @@ func main() {
 
     // 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)
+    markdownPath, err := exec.LookPath("markdown")
+    check(err)
+    pygmentizePath, err := exec.LookPath("pygmentize")
+    check(err)
+    fmt.Println(markdownPath, pygmentizePath)
 
     // Read the source file in.
     sourceBytes, err := ioutil.ReadFile(os.Args[1])
     check(err)
-    source := string(sourceBytes)
-    fmt.Print(source)
 
-    // ...
+    // Split into lines.
+    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"
+        }
+    }
+    for _, seg := range segments {
+        fmt.Printf("%#v\n", *seg)
+    }
 }