From 6b625c0e8dedb8c38e251df7d11ce215b9cc1fdb Mon Sep 17 00:00:00 2001
From: Qi Xiao <xiaqqaix@gmail.com>
Date: Tue, 23 Feb 2016 13:29:10 +0100
Subject: [PATCH] New builtin "tilde-abbr".

---
 eval/builtin_func.go |  7 +++++++
 util/getwd.go        | 13 +++++++++----
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/eval/builtin_func.go b/eval/builtin_func.go
index de530102..e1f10af1 100644
--- a/eval/builtin_func.go
+++ b/eval/builtin_func.go
@@ -96,6 +96,8 @@ func init() {
 
 		&BuiltinFn{"fg", wrapFn(fg)},
 
+		&BuiltinFn{"tilde-abbr", wrapFn(tildeAbbr)},
+
 		&BuiltinFn{"-sleep", wrapFn(_sleep)},
 		&BuiltinFn{"-stack", wrapFn(_stack)},
 		&BuiltinFn{"-log", wrapFn(_log)},
@@ -639,6 +641,11 @@ func fg(ec *EvalCtx, pids ...int) {
 	throwCompositeError(errors)
 }
 
+func tildeAbbr(ec *EvalCtx, path string) {
+	out := ec.ports[1].Chan
+	out <- String(util.TildeAbbr(path))
+}
+
 func _sleep(ec *EvalCtx, t float64) {
 	d := time.Duration(float64(time.Second) * t)
 	select {
diff --git a/util/getwd.go b/util/getwd.go
index f81377fd..ed673e03 100644
--- a/util/getwd.go
+++ b/util/getwd.go
@@ -12,13 +12,18 @@ func Getwd() string {
 	if err != nil {
 		return "?"
 	}
+	return TildeAbbr(pwd)
+}
+
+// TildeAbbr abbreviates the user's home directory to ~.
+func TildeAbbr(path string) string {
 	home, err := GetHome("")
 	if err == nil {
-		if pwd == home {
+		if path == home {
 			return "~"
-		} else if strings.HasPrefix(pwd, home+"/") {
-			return "~" + pwd[len(home):]
+		} else if strings.HasPrefix(path, home+"/") {
+			return "~" + path[len(home):]
 		}
 	}
-	return pwd
+	return path
 }