From f479c924b8b0b70e1fa627a92405b6bb87d1097a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89tienne=20Vallette=20d=27Osia?= <dohzya@gmail.com>
Date: Tue, 3 Mar 2015 15:50:53 +0900
Subject: [PATCH] Add Command's RemoveCommand method
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This method removes children commands of an existing command.

This allows to build CLI clients that can be extended by 3rd party tools,
for instance by adding commands _and replacing the “version” command_.

For now the 1st defined command will be executed, so it is not possible
to override an existing command. But anyway, deleting old command then
adding a new one is the ultimate way to be certain there is no
confusion.
---
 command.go | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/command.go b/command.go
index b1b69e3c..3538ccdc 100644
--- a/command.go
+++ b/command.go
@@ -581,6 +581,40 @@ func (c *Command) AddCommand(cmds ...*Command) {
 	}
 }
 
+// AddCommand removes one or more commands from a parent command.
+func (c *Command) RemoveCommand(cmds ...*Command) {
+	commands := []*Command{}
+main:
+	for _, command := range c.commands {
+		for _, cmd := range cmds {
+			if command == cmd {
+				command.parent = nil
+				continue main
+			}
+		}
+		commands = append(commands, command)
+	}
+	c.commands = commands
+	// recompute all lengths
+	c.commandsMaxUseLen = 0
+	c.commandsMaxCommandPathLen = 0
+	c.commandsMaxNameLen = 0
+	for _, command := range c.commands {
+		usageLen := len(command.Use)
+		if usageLen > c.commandsMaxUseLen {
+			c.commandsMaxUseLen = usageLen
+		}
+		commandPathLen := len(command.CommandPath())
+		if commandPathLen > c.commandsMaxCommandPathLen {
+			c.commandsMaxCommandPathLen = commandPathLen
+		}
+		nameLen := len(command.Name())
+		if nameLen > c.commandsMaxNameLen {
+			c.commandsMaxNameLen = nameLen
+		}
+	}
+}
+
 // Convenience method to Print to the defined output
 func (c *Command) Print(i ...interface{}) {
 	fmt.Fprint(c.Out(), i...)