From 6f8cfa703a6b5eabeef4b957d14cfc200a16c908 Mon Sep 17 00:00:00 2001
From: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Date: Sun, 13 Jul 2014 15:18:45 +0100
Subject: [PATCH] Add Args.Swap command for swapping arguments

The usecase:
my-cli user <USERID> set <FIELD> <VALUE>

Being able to swap <USERID> with set argument, we can have nested subcommands while preserving all variable arguments along the way.
---
 context.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/context.go b/context.go
index b2c51bb..1e023ce 100644
--- a/context.go
+++ b/context.go
@@ -140,6 +140,15 @@ func (a Args) Present() bool {
 	return len(a) != 0
 }
 
+// Swaps arguments at the given indexes
+func (a Args) Swap(from, to int) error {
+	if from >= len(a) || to >= len(a) {
+		return errors.New("index out of range")
+	}
+	a[from], a[to] = a[to], a[from]
+	return nil
+}
+
 func lookupInt(name string, set *flag.FlagSet) int {
 	f := set.Lookup(name)
 	if f != nil {