init go rewrite

um.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+)
+
+type Subcommand string
+
+const (
+	tag  Subcommand = "tag"
+	next Subcommand = "next"
+	last Subcommand = "last"
+	sort Subcommand = "sort"
+)
+
+var help string = fmt.Sprintf("um [%s | %s | %s | %s]", tag, next, last, sort)
+
+type Flag string
+
+const (
+	query  Flag = "query"
+	invert Flag = "invert"
+	key    Flag = "key"
+)
+
+func (f Flag) Dash() string {
+	return fmt.Sprintf("--%s", f)
+}
+
+// prepend --flag to args if a flag isn't there:
+// allows trailing flags:
+// um tag foo --invert
+// becomes:
+// um tag --query foo --invert
+func prependFlagToArgs(args []string, flag Flag) []string {
+	if len(args) >= 1 && !strings.HasPrefix(args[0], "-") {
+		args = append([]string{flag.Dash()}, args...)
+	}
+	return args
+}
+
+func main() {
+	tagFlags := flag.NewFlagSet(string(tag), flag.ExitOnError)
+	tagQuery := tagFlags.String(string(query), "", "tag query")
+	tagInvert := tagFlags.Bool(string(invert), false, "invert match")
+
+	sortFlags := flag.NewFlagSet(string(sort), flag.ExitOnError)
+	sortKey := sortFlags.String(string(key), "", "filename of ordered list to use as key")
+
+	// TODO: do something useful:
+	// run empty tag query?
+	if len(os.Args) < 2 {
+		fmt.Println(help)
+		os.Exit(1)
+	}
+
+	cmd := Subcommand(os.Args[1])
+	args := os.Args[2:]
+
+	switch cmd {
+	case next:
+		fmt.Printf("args: %#v\n", args)
+	case tag:
+		tagFlags.Parse(prependFlagToArgs(args, query))
+		fmt.Println(tag)
+		fmt.Printf("query: %#v\n", *tagQuery)
+		fmt.Printf("invert: %#v\n", *tagInvert)
+		fmt.Printf("args: %#v\n", tagFlags.Args())
+		tagFlags.Usage()
+	case sort:
+		sortFlags.Parse(args)
+		fmt.Println("subcmd sort")
+		fmt.Printf("key: %#v\n", *sortKey)
+		fmt.Printf("args: %#v\n", sortFlags.Args())
+		sortFlags.Usage()
+	default:
+		fmt.Println(help)
+		os.Exit(1)
+	}
+}