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+// SPDX-FileCopyrightText: 2020 Ethel Morgan
+//
+// SPDX-License-Identifier: MIT
+
+/*
+Package flag wraps Go's built-in flag package, with the addition of idiomatic custom flags.
+
+Custom Flags
+
+Custom flags are wrappers around Go's built-in string flags, with a parser
+func. They can be used to parse custom flag types, or to have custom flag
+validators, while keeping the parsing & validation with the flag's definition.
+
+	var (
+		urlFlag = flag.Custom("url", "", "url to GET", func(raw string) (interface{}, error) {
+			return url.Parse(raw)
+		})
+		outputFlag = flag.Custom("output", "", "output format", func(raw string) (interface{}, error) {
+			if !(raw == "table" || raw == "json") {
+				return nil, fmt.Errorf("must be either json or table, got %v", raw)
+			}
+			return raw, nil
+		})
+	)
+
+	func main() {
+		flag.Parse()
+		urlFlag := (*urlFlag).(*url.URL)
+		outputFlag := (*outputFlag).(string)
+	}
+
+*/
+package flag