skate-map: a bit more help output

1 files changed, 8 insertions, 7 deletions

diff --git a/skate/cmd/skate-map/main.go b/skate/cmd/skate-map/main.go
index d5f22fd..227acf2 100644
--- a/skate/cmd/skate-map/main.go
+++ b/skate/cmd/skate-map/main.go
@@ -54,16 +54,18 @@ var (
 	extraValue  = flag.String("x", "", "extra value to pass to configurable mappers")
 	bestEffort  = flag.Bool("B", false, "best effort")
 	logFile     = flag.String("log", "", "log filename")
-	skipOnEmpty = flag.Int("skip-on-empty", -1, "omit docs with empty value in given field, zero indexed")
+	skipOnEmpty = flag.Int("skip-on-empty", -1, "omit docs with empty value in given column (zero indexed)")
+
+	help = `skate-map available mappers
+
+    $ skate-map -m ts < file.ndj > file.tsv
+	`
 )
 
 func main() {
 	flag.Parse()
-	// TODO
-	// [ ] add prefixes and a way to derive multiple keys in one go
-	// [ ] how to store multiple keys, sorted?
-	// [ ] maybe wrap jq and parallel for arbitrary nested keys
 	availableMappers := map[string]skate.Mapper{
+		// Add new mapper functions here.
 		"id": skate.Identity,
 		"ff": skate.CreateFixedMapper(*extraValue),
 		"ti": skate.MapperTitle,
@@ -102,8 +104,7 @@ func main() {
 			}
 		}
 	default:
-		fmt.Println("skate-map available mappers")
-		fmt.Println()
+		fmt.Println(help)
 		w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
 		for k, v := range availableMappers {
 			fmt.Fprintf(w, "%s\t%s\n", k, skate.NameOf(v))