library: os.Expand

_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))
+}