Forbid the serve command to work on a non-existent directory

git-svn-id: file:///srv/svn/repo/aya/trunk@92 cec141ff-132a-4243-88a5-ce187bd62f94

cmd/aya/buildall.go

@@ -38,7 +38,7 @@ func buildAll(watch bool) {
 					run(vars, "prehook")
 					modified = true
 				}
-				fmt.Println("GEN", path)
+				fmt.Println(path)
 				return build(path, nil, vars)
 			}
 			return nil

cmd/aya/main.go

@@ -50,7 +50,12 @@ func main() {
 	case "help":
 		aya.PrintUsage()
 	case "serve":
-		aya.HttpServe(PUBDIR, 8000)
+		d, err := os.Stat(PUBDIR)
+		if err != nil {
+			log.Fatal("[aya.HttpServe] I see, you want me to serve a non-existent directory, huh?")
+		} else {
+			aya.HttpServe(fmt.Sprint(d), 8000)
+		}
 	case "var":
 		if len(args) == 0 {
 			log.Fatal("[var] Filename expected")