substitute location in error output with acme addr

uncrust.go

@@ -7,6 +7,8 @@ import (
 	"log"
 	"os"
 	"os/exec"
+	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -17,6 +19,8 @@ import (
 var (
 	fl_lang    = flag.String("l", "C", "Language")
 	fl_verbose = flag.Bool("v", false, "Verbosity on")
+
+	pos_rx = regexp.MustCompile(`File: stdin, orig line is ([\d]+), orig col is ([\d])`)
 )
 
 func main() {
@@ -54,7 +58,9 @@ func main() {
 		if _, ok := e.(*exec.ExitError); ok {
 			str := stderr.String()
 			if len(samfile) != 0 {
+				samfile = "./" + filepath.Base(samfile)
 				str = strings.ReplaceAll(str, "stdin, open_line is ", samfile+":")
+				str = pos_rx.ReplaceAllString(str, fmt.Sprintf("%s:$1:#$2", samfile))
 			}
 			log.Fatal("error: " + str)
 		}
@@ -87,11 +93,11 @@ func main() {
 	}
 
 	if len(edits) > 0 {
-		win.Write("ctl", []byte("mark"))
-		win.Write("ctl", []byte("nomark"))
 		if *fl_verbose {
 			log.Printf("Applying %d diffs:\n%s\n", len(edits), pretty(edits, samfile))
 		}
+		win.Write("ctl", []byte("mark"))
+		win.Write("ctl", []byte("nomark"))
 	}
 
 	for i := len(edits) - 1; i >= 0; i-- {