add ability to parse []string types

command.go

@@ -1,19 +1,19 @@
 package cli
 
 import (
-	"os"
 	"fmt"
 	"io/ioutil"
+	"os"
 	"strings"
 )
 
 type Command struct {
-	Name          string
-	ShortName     string
-	Usage         string
-	Description   string
-	Action      func (context *Context)
-	Flags         []Flag
+	Name        string
+	ShortName   string
+	Usage       string
+	Description string
+	Action      func(context *Context)
+	Flags       []Flag
 }
 
 func (c Command) Run(ctx *Context) {
@@ -52,7 +52,6 @@ func (c Command) Run(ctx *Context) {
 
 	context := NewContext(ctx.App, set, ctx.globalSet)
 	checkCommandHelp(context, c.Name)
-
 	c.Action(context)
 }
 

context.go

@@ -34,6 +34,10 @@ func (c *Context) String(name string) string {
 	return c.lookupString(name, c.flagSet)
 }
 
+func (c *Context) StringSlice(name string) flag.Value {
+	return c.lookupStringSlice(name, c.flagSet)
+}
+
 // Looks up the value of a global int flag, returns 0 if no int flag exists
 func (c *Context) GlobalInt(name string) int {
 	return c.lookupInt(name, c.globalSet)
@@ -75,6 +79,15 @@ func (c *Context) lookupString(name string, set *flag.FlagSet) string {
 	return ""
 }
 
+func (c *Context) lookupStringSlice(name string, set *flag.FlagSet) flag.Value {
+	f := set.Lookup(name)
+	if f != nil {
+		return f.Value
+	}
+
+	return nil
+}
+
 func (c *Context) lookupBool(name string, set *flag.FlagSet) bool {
 	f := set.Lookup(name)
 	if f != nil {

flag.go

@@ -8,14 +8,48 @@ type Flag interface {
 	Apply(*flag.FlagSet)
 }
 
+type SliceFlag interface {
+	Value() []string
+}
+
 func flagSet(name string, flags []Flag) *flag.FlagSet {
 	set := flag.NewFlagSet(name, flag.ContinueOnError)
+
 	for _, f := range flags {
 		f.Apply(set)
 	}
 	return set
 }
 
+type StringSlice []string
+
+func (i *StringSlice) Set(value string) error {
+	*i = append(*i, value)
+	return nil
+}
+
+func (i *StringSlice) String() string {
+	return fmt.Sprintf("%s", *i)
+}
+
+func (i *StringSlice) Value() []string {
+	return *i
+}
+
+type StringSliceFlag struct {
+	Name  string
+	Value *StringSlice
+	Usage string
+}
+
+func (f StringSliceFlag) String() string {
+	return fmt.Sprintf("%s%v '%v'\t%v", prefixFor(f.Name), f.Name, "-"+f.Name+" option -"+f.Name+" option", f.Usage)
+}
+
+func (f StringSliceFlag) Apply(set *flag.FlagSet) {
+	set.Var(f.Value, f.Name, f.Usage)
+}
+
 type BoolFlag struct {
 	Name  string
 	Usage string