1 files changed, 71 insertions, 0 deletions
diff --git a/opts.go b/opts.go
new file mode 100644
index 0000000..c7ab697
--- /dev/null
+++ b/opts.go
@@ -0,0 +1,71 @@
+package opts
+
+type ArgMode int
+
+const (
+	None ArgMode = iota
+	Required
+	Optional
+)
+
+type Flag struct {
+	Key   rune
+	Value string
+}
+
+type LongOpt struct {
+	Short rune
+	Long  string
+	Arg   ArgMode
+}
+
+func Get(args []string, optstr string) (flags []Flag, optind int, err error) {
+	argmap := make(map[rune]bool)
+
+	rs := []rune(optstr)
+	for i, r := range rs {
+		if r != ':' {
+			argmap[r] = false
+		} else if i > 0 {
+			argmap[rs[i-1]] = true
+		}
+	}
+
+	for i := 1; i < len(args); i++ {
+		arg := args[i]
+		if len(arg) == 0 || arg == "-" || arg[0] != '-' {
+			optind = i
+			return
+		} else if arg == "--" {
+			optind = i + 1
+			return
+		}
+
+		rs := []rune(arg[1:])
+	outer:
+		for j, r := range rs {
+			argp, ok := argmap[r]
+			if !ok {
+				return nil, 0, ErrBadOption(r)
+			}
+
+			switch {
+			case argp && j < len(rs)-1:
+				s := string(rs[j+1:])
+				flags = append(flags, Flag{r, s})
+				break outer
+			case argp:
+				i++
+				if i >= len(args) {
+					return nil, 0, ErrNoArgument(r)
+				}
+				flags = append(flags, Flag{r, args[i]})
+				break outer
+			}
+			flags = append(flags, Flag{Key: r})
+		}
+	}
+
+	optind = len(args)
+	return
+}