From f91b5b558a354da6f1381fa8ca37ac78f5e859f3 Mon Sep 17 00:00:00 2001
From: John Guo <john@johng.cn>
Date: Wed, 24 Nov 2021 22:45:34 +0800
Subject: [PATCH] improve package gcmd

---
 os/gcmd/gcmd_parser.go | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/os/gcmd/gcmd_parser.go b/os/gcmd/gcmd_parser.go
index 746381c9a..1ed5f28eb 100644
--- a/os/gcmd/gcmd_parser.go
+++ b/os/gcmd/gcmd_parser.go
@@ -8,6 +8,7 @@
 package gcmd
 
 import (
+	"context"
 	"os"
 	"strings"
 
@@ -30,6 +31,16 @@ type Parser struct {
 	commandFuncMap   map[string]func() // Command function map for function handler.
 }
 
+// ParserFromCtx retrieves and returns Parser from context.
+func ParserFromCtx(ctx context.Context) *Parser {
+	if v := ctx.Value(CtxKeyParser); v != nil {
+		if p, ok := v.(*Parser); ok {
+			return p
+		}
+	}
+	return nil
+}
+
 // Parse creates and returns a new Parser with os.Args and supported options.
 //
 // Note that the parameter `supportedOptions` is as [option name: need argument], which means