1 files changed, 48 insertions, 0 deletions
diff --git a/parsefuncs.go b/parsefuncs.go
new file mode 100644
index 0000000..0263a5a
--- /dev/null
+++ b/parsefuncs.go
@@ -0,0 +1,48 @@
+// SPDX-FileCopyrightText: 2020 Ethel Morgan
+//
+// SPDX-License-Identifier: MIT
+
+package flag
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+func RequiredString(raw string) (interface{}, error) {
+	if raw == "" {
+		return nil, errors.New("must not be empty")
+	}
+	return raw, nil
+}
+
+func StringEnum(values ...string) ParseFunc {
+	return func(raw string) (interface{}, error) {
+		for _, value := range values {
+			if value == raw {
+				return raw, nil
+			}
+		}
+		return raw, fmt.Errorf("must be one of %q", values)
+	}
+}
+
+func IntList(raw string) (interface{}, error) {
+	var ints []int
+
+	if raw == "" {
+		return ints, nil
+	}
+
+	for _, raw := range strings.Split(raw, ",") {
+		i, err := strconv.Atoi(raw)
+		if err != nil {
+			return ints, err
+		}
+		ints = append(ints, i)
+	}
+
+	return ints, nil
+}