From cbd891785ebfcf058c1ed4ca09096130f312fab4 Mon Sep 17 00:00:00 2001
From: xushiwei <x@goplus.org>
Date: Mon, 29 Jul 2024 11:06:33 +0800
Subject: [PATCH] library: os.Expand

---
 _cmptest/envexpand/expand.go | 20 ++++++++++++++++++++
 internal/lib/os/env.go       |  2 --
 2 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 _cmptest/envexpand/expand.go

diff --git a/_cmptest/envexpand/expand.go b/_cmptest/envexpand/expand.go
new file mode 100644
index 00000000..0c4baaf0
--- /dev/null
+++ b/_cmptest/envexpand/expand.go
@@ -0,0 +1,20 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+func main() {
+	mapper := func(placeholderName string) string {
+		switch placeholderName {
+		case "DAY_PART":
+			return "morning"
+		case "NAME":
+			return "Gopher"
+		}
+		return ""
+	}
+
+	fmt.Println(os.Expand("Good ${DAY_PART}, $NAME!", mapper))
+}
diff --git a/internal/lib/os/env.go b/internal/lib/os/env.go
index 7c0f3174..550dac19 100644
--- a/internal/lib/os/env.go
+++ b/internal/lib/os/env.go
@@ -10,7 +10,6 @@ import (
 	"syscall"
 )
 
-/* TODO(xsw):
 // Expand replaces ${var} or $var in the string based on the mapping function.
 // For example, os.ExpandEnv(s) is equivalent to os.Expand(s, os.Getenv).
 func Expand(s string, mapping func(string) string) string {
@@ -94,7 +93,6 @@ func getShellName(s string) (string, int) {
 	}
 	return s[:i], i
 }
-*/
 
 // Getenv retrieves the value of the environment variable named by the key.
 // It returns the value, which will be empty if the variable is not present.