From 31eb6be473df4930679259cfa284ef4cc80d1d8c Mon Sep 17 00:00:00 2001
From: chzyer <0@0xdf.com>
Date: Fri, 2 Sep 2016 20:10:31 +0800
Subject: [PATCH] support insert tag char (#74)

---
 complete_tag.go | 7 +++++++
 readline.go     | 3 +++
 runebuf.go      | 8 +++++++-
 runes.go        | 4 ++++
 4 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 complete_tag.go

diff --git a/complete_tag.go b/complete_tag.go
new file mode 100644
index 0000000..2039458
--- /dev/null
+++ b/complete_tag.go
@@ -0,0 +1,7 @@
+package readline
+
+type TabCompleter struct{}
+
+func (t *TabCompleter) Do([]rune, int) ([][]rune, int) {
+	return [][]rune{[]rune("\t")}, 0
+}
diff --git a/readline.go b/readline.go
index 4b866fb..20a2108 100644
--- a/readline.go
+++ b/readline.go
@@ -93,6 +93,9 @@ func (c *Config) Init() error {
 		c.EOFPrompt = ""
 	}
 
+	if c.AutoComplete == nil {
+		c.AutoComplete = &TabCompleter{}
+	}
 	if c.FuncGetWidth == nil {
 		c.FuncGetWidth = GetScreenWidth
 	}
diff --git a/runebuf.go b/runebuf.go
index e402aed..538832e 100644
--- a/runebuf.go
+++ b/runebuf.go
@@ -430,7 +430,13 @@ func (r *RuneBuffer) output() []byte {
 		}
 
 	} else {
-		buf.Write([]byte(string(r.buf)))
+		for idx := range r.buf {
+			if r.buf[idx] == '\t' {
+				buf.WriteString(strings.Repeat(" ", TabWidth))
+			} else {
+				buf.WriteRune(r.buf[idx])
+			}
+		}
 		if r.isInLineEdge() {
 			buf.Write([]byte(" \b"))
 		}
diff --git a/runes.go b/runes.go
index b85af7a..8ed54ce 100644
--- a/runes.go
+++ b/runes.go
@@ -6,6 +6,7 @@ import (
 )
 
 var runes = Runes{}
+var TabWidth = 4
 
 type Runes struct{}
 
@@ -98,6 +99,9 @@ var doubleWidth = []*unicode.RangeTable{
 }
 
 func (Runes) Width(r rune) int {
+	if r == '\t' {
+		return TabWidth
+	}
 	if unicode.IsOneOf(zeroWidth, r) {
 		return 0
 	}