Add WrapCSV, handle nil flag.Values

README.md

@@ -105,6 +105,7 @@ Here's a compact overview:
 | [URL](https://godoc.org/github.com/sgreben/flagvar#URL)         | https://github.com | *url.URL                             |
 | [URLs](https://godoc.org/github.com/sgreben/flagvar#URLs)        | https://github.com | []*url.URL                           |
 | [Wrap](https://godoc.org/github.com/sgreben/flagvar#Wrap)        |                    |                                      |
+| [WrapCSV](https://godoc.org/github.com/sgreben/flagvar#WrapCSV)        |                    |                                      |
 | [WrapFunc](https://godoc.org/github.com/sgreben/flagvar#WrapFunc)    |                    |                                      |
 | [WrapPointer](https://godoc.org/github.com/sgreben/flagvar#WrapPointer)    |                    |                                      |
 

alternative.go

@@ -24,5 +24,8 @@ func (fv *Alternative) String() string {
 	if fv.EitherOk {
 		return fv.Either.String()
 	}
-	return fv.Or.String()
+	if fv.Or != nil {
+		return fv.Or.String()
+	}
+	return ""
 }

wrap.go

@@ -1,6 +1,9 @@
 package flagvar
 
-import "flag"
+import (
+	"flag"
+	"strings"
+)
 
 // WrapPointer wraps a pointer to a `flag.Value`
 // This can be used to switch between different argument parsers.
@@ -14,6 +17,9 @@ func (fv *WrapPointer) Set(v string) error {
 }
 
 func (fv WrapPointer) String() string {
+	if fv.Value == nil || (*fv.Value) == nil {
+		return ""
+	}
 	return (*fv.Value).String()
 }
 
@@ -27,6 +33,9 @@ func (fv WrapFunc) Set(v string) error {
 }
 
 func (fv WrapFunc) String() string {
+	if fv == nil {
+		return ""
+	}
 	return fv().String()
 }
 
@@ -46,5 +55,51 @@ func (fv *Wrap) Set(v string) error {
 }
 
 func (fv *Wrap) String() string {
+	if fv.Value == nil {
+		return ""
+	}
+	return fv.Value.String()
+}
+
+// WrapCSV wraps a `flag.Value` and calls `UpdatedOne` after each single value and `UpdatedAll` after each CSV batch.
+// The `Separator` field is used instead of the comma when set.
+type WrapCSV struct {
+	Value      flag.Value
+	Separator  string
+	UpdatedOne func()
+	UpdatedAll func()
+	StringFunc func() string
+}
+
+// Set is flag.Value.Set
+func (fv *WrapCSV) Set(v string) error {
+	separator := fv.Separator
+	if separator == "" {
+		separator = ","
+	}
+	parts := strings.Split(v, separator)
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		err := fv.Value.Set(part)
+		if err != nil {
+			return err
+		}
+		if fv.UpdatedOne != nil {
+			fv.UpdatedOne()
+		}
+	}
+	if fv.UpdatedAll != nil {
+		fv.UpdatedAll()
+	}
+	return nil
+}
+
+func (fv *WrapCSV) String() string {
+	if fv.StringFunc != nil {
+		return fv.StringFunc()
+	}
+	if fv.Value == nil {
+		return ""
+	}
 	return fv.Value.String()
 }

wrap_test.go

@@ -2,7 +2,10 @@ package flagvar_test
 
 import (
 	"flag"
+	"fmt"
 	"reflect"
+	"sort"
+	"strings"
 	"testing"
 
 	"github.com/sgreben/flagvar"
@@ -64,3 +67,86 @@ func TestWrap(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestWrapCSV(t *testing.T) {
+	sv := &flagvar.Strings{}
+	fv := flagvar.WrapCSV{Value: sv}
+	var fs flag.FlagSet
+	fs.Var(&fv, "wrap-csv", "")
+
+	err := fs.Parse([]string{"-wrap-csv", "abc,def", "-wrap-csv", "xyz"})
+	if err != nil {
+		t.Fail()
+	}
+	if !reflect.DeepEqual(sv.Values, []string{"abc", "def", "xyz"}) {
+		t.Fail()
+	}
+}
+
+func TestWrapCSVFail(t *testing.T) {
+	sv := &flagvar.IP{}
+	fv := flagvar.WrapCSV{Value: sv}
+	var fs flag.FlagSet
+	fs.Var(&fv, "wrap-csv", "")
+
+	err := fs.Parse([]string{"-wrap-csv", "127.0.0.1,def"})
+	if err == nil {
+		t.Fail()
+	}
+}
+
+func TestWrapCSVSeparator(t *testing.T) {
+	sv := &flagvar.Strings{}
+	fv := flagvar.WrapCSV{
+		Value:     sv,
+		Separator: ";",
+	}
+	var fs flag.FlagSet
+	fs.Var(&fv, "wrap-csv", "")
+
+	err := fs.Parse([]string{"-wrap-csv", "abc;def", "-wrap-csv", "xyz"})
+	if err != nil {
+		t.Fail()
+	}
+	if !reflect.DeepEqual(sv.Values, []string{"abc", "def", "xyz"}) {
+		t.Fail()
+	}
+}
+
+func TestWrapCSVUpdated(t *testing.T) {
+	sv := &flagvar.Assignment{}
+	current := map[string]string{}
+	final := map[string]string{}
+	fv := flagvar.WrapCSV{
+		Value: sv,
+		UpdatedOne: func() {
+			current[sv.Value.Key] = sv.Value.Value
+		},
+		UpdatedAll: func() {
+			final = current
+			current = map[string]string{}
+		},
+		StringFunc: func() string {
+			var out []string
+			for k, v := range final {
+				out = append(out, fmt.Sprintf("%s=%s", k, v))
+			}
+			sort.Strings(out)
+			return strings.Join(out, ",")
+		},
+	}
+	var fs flag.FlagSet
+	fs.Var(&fv, "wrap-csv", "")
+
+	err := fs.Parse([]string{"-wrap-csv", "xyz=abc", "-wrap-csv", "abc=def,def=xyz"})
+	if err != nil {
+		t.Fail()
+	}
+	fmt.Println(final)
+	if !reflect.DeepEqual(final, map[string]string{"abc": "def", "def": "xyz"}) {
+		t.Fail()
+	}
+	if !reflect.DeepEqual(fv.String(), `abc=def,def=xyz`) {
+		t.Fail()
+	}
+}