basic command completion for single match

comp.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+)
+
+var (
+	gCmdWords = []string{"set", "map", "cmd"}
+	gOptWords = []string{
+		"preview",
+		"nopreview",
+		"hidden",
+		"nohidden",
+		"tabstop",
+		"scrolloff",
+		"sortby",
+		"showinfo",
+		"opener",
+		"ratios",
+	}
+)
+
+func matchWord(s string, words []string) string {
+	var match string
+
+	for _, w := range words {
+		if strings.HasPrefix(w, s) {
+			if match != "" {
+				return s
+			}
+			match = w
+		}
+	}
+
+	if match != "" {
+		return match + " "
+	}
+
+	return s
+}
+
+func matchFile(s string) string {
+	var match string
+
+	wd, err := os.Getwd()
+	if err != nil {
+		log.Print(err)
+	}
+
+	fi, err := ioutil.ReadDir(wd)
+	if err != nil {
+		log.Print(err)
+	}
+
+	for _, f := range fi {
+		if strings.HasPrefix(f.Name(), s) {
+			if match != "" {
+				return s
+			}
+			match = f.Name()
+		}
+	}
+
+	if match != "" {
+		return match + " "
+	}
+
+	return s
+}
+
+func compCmd(acc []rune) []rune {
+	if len(acc) == 0 || acc[len(acc)-1] == ' ' {
+		return acc
+	}
+
+	s := string(acc)
+	f := strings.Fields(s)
+
+	switch len(f) {
+	case 0: // do nothing
+	case 1:
+		words := gCmdWords
+		for c, _ := range gOpts.cmds {
+			words = append(words, c)
+		}
+		return []rune(matchWord(s, words))
+	default:
+		switch f[0] {
+		case "set":
+			opt := matchWord(f[1], gOptWords)
+			ret := []rune(f[0])
+			ret = append(ret, ' ')
+			ret = append(ret, []rune(opt)...)
+			return ret
+		case "map", "cmd": // do nothing
+		default:
+			ret := []rune(f[0])
+			ret = append(ret, ' ')
+			for i := 1; i < len(f); i++ {
+				name := matchFile(f[i])
+				ret = append(ret, []rune(name)...)
+			}
+			return ret
+		}
+	}
+
+	return acc
+}

ui.go

@@ -445,6 +445,8 @@ func (ui *UI) prompt(pref string) string {
 					termbox.SetCursor(win.x, win.y)
 					termbox.Flush()
 					return string(acc)
+				case termbox.KeyTab:
+					acc = compCmd(acc)
 				case termbox.KeyEsc:
 					return ""
 				}