Merge pull request #483 from urfave/merging-from-v1

Merging from v1

.travis.yml

@@ -23,15 +23,11 @@ matrix:
   - go: 1.6.2
     os: osx
     env: pip_install="sudo pip install"
-  - go: 1.1.2
-    install: go get -v .
-    before_script: echo skipping gfmxr on ${TRAVIS_GO_VERSION}
-    script:
-    - ./runtests vet
-    - ./runtests test
 
 before_script:
 - $pip_install flake8
+- go get github.com/urfave/gfmxr/...
+- go get golang.org/x/tools/cmd/goimports
 - if [ ! -f node_modules/.bin/markdown-toc ] ; then
     npm install markdown-toc ;
   fi
@@ -43,6 +39,7 @@ before_script:
 
 script:
 - flake8 runtests cli-v1-to-v2
+- ./runtests gen
 - ./runtests vet
 - ./runtests test
 - ./runtests gfmxr

CHANGELOG.md

@@ -34,6 +34,13 @@
 
 ## [Unreleased] - (1.x series)
 ### Added
+- Flag type code generation via `go generate`
+
+### Changed
+- Raise minimum tested/supported Go version to 1.2+
+
+## [1.18.0] - 2016-06-27
+### Added
 - `./runtests` test runner with coverage tracking by default
 - testing on OS X
 - testing on Windows
@@ -46,6 +53,9 @@
 ### Fixed
 - Printing of command aliases in help text
 - Printing of visible flags for both struct and struct pointer flags
+- Display the `help` subcommand when using `CommandCategories`
+- No longer swallows `panic`s that occur within the `Action`s themselves when
+  detecting the signature of the `Action` field
 
 ## [1.17.0] - 2016-05-09
 ### Added
@@ -326,7 +336,8 @@ signature of `func(*cli.Context) error`, as defined by `cli.ActionFunc`.
 ### Added
 - Initial implementation.
 
-[Unreleased]: https://github.com/urfave/cli/compare/v1.17.0...HEAD
+[Unreleased]: https://github.com/urfave/cli/compare/v1.18.0...HEAD
+[1.18.0]: https://github.com/urfave/cli/compare/v1.17.0...v1.18.0
 [1.17.0]: https://github.com/urfave/cli/compare/v1.16.0...v1.17.0
 [1.16.0]: https://github.com/urfave/cli/compare/v1.15.0...v1.16.0
 [1.15.0]: https://github.com/urfave/cli/compare/v1.14.0...v1.15.0

README.md

@@ -60,18 +60,16 @@ organized, and expressive!
 
 ## Installation
 
-Make sure you have a working Go environment.  Go version 1.1+ is required for
+Make sure you have a working Go environment.  Go version 1.2+ is supported.  [See
-core cli, whereas use of the [`./altsrc`](./altsrc) input extensions requires Go
+the install instructions for Go](http://golang.org/doc/install.html).
-version 1.2+. [See the install
-instructions](http://golang.org/doc/install.html).
 
 To install cli, simply run:
 ```
 $ go get github.com/urfave/cli
 ```
 
-Make sure your `PATH` includes to the `$GOPATH/bin` directory so your commands
+Make sure your `PATH` includes the `$GOPATH/bin` directory so your commands can
-can be easily used:
+be easily used:
 ```
 export PATH=$PATH:$GOPATH/bin
 ```

altsrc/altsrc.go

@@ -0,0 +1,3 @@
+package altsrc
+
+//go:generate python ../generate-flag-types altsrc -i ../flag-types.json -o flag_generated.go

altsrc/flag.go

@@ -1,7 +1,6 @@
 package altsrc
 
 import (
-	"flag"
 	"fmt"
 	"os"
 	"strconv"
@@ -62,18 +61,6 @@ func InitInputSourceWithContext(flags []cli.Flag, createInputSource func(context
 	}
 }
 
-// GenericFlag is the flag type that wraps *cli.GenericFlag to allow
-// for other values to be specified
-type GenericFlag struct {
-	*cli.GenericFlag
-	set *flag.FlagSet
-}
-
-// NewGenericFlag creates a new GenericFlag
-func NewGenericFlag(flag *cli.GenericFlag) *GenericFlag {
-	return &GenericFlag{GenericFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a generic value to the flagSet if required
 func (f *GenericFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -93,25 +80,6 @@ func (f *GenericFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourc
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped GenericFlag.Apply
-func (f *GenericFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-	f.GenericFlag.Apply(set)
-}
-
-// StringSliceFlag is the flag type that wraps *cli.StringSliceFlag to allow
-// for other values to be specified
-type StringSliceFlag struct {
-	*cli.StringSliceFlag
-	set *flag.FlagSet
-}
-
-// NewStringSliceFlag creates a new StringSliceFlag
-func NewStringSliceFlag(flag *cli.StringSliceFlag) *StringSliceFlag {
-	return &StringSliceFlag{StringSliceFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a StringSlice value to the flagSet if required
 func (f *StringSliceFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -134,25 +102,6 @@ func (f *StringSliceFlag) ApplyInputSourceValue(context *cli.Context, isc InputS
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped StringSliceFlag.Apply
-func (f *StringSliceFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-	f.StringSliceFlag.Apply(set)
-}
-
-// IntSliceFlag is the flag type that wraps *cli.IntSliceFlag to allow
-// for other values to be specified
-type IntSliceFlag struct {
-	*cli.IntSliceFlag
-	set *flag.FlagSet
-}
-
-// NewIntSliceFlag creates a new IntSliceFlag
-func NewIntSliceFlag(flag *cli.IntSliceFlag) *IntSliceFlag {
-	return &IntSliceFlag{IntSliceFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a IntSlice value if required
 func (f *IntSliceFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -175,25 +124,6 @@ func (f *IntSliceFlag) ApplyInputSourceValue(context *cli.Context, isc InputSour
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped IntSliceFlag.Apply
-func (f *IntSliceFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-	f.IntSliceFlag.Apply(set)
-}
-
-// BoolFlag is the flag type that wraps *cli.BoolFlag to allow
-// for other values to be specified
-type BoolFlag struct {
-	*cli.BoolFlag
-	set *flag.FlagSet
-}
-
-// NewBoolFlag creates a new BoolFlag
-func NewBoolFlag(flag *cli.BoolFlag) *BoolFlag {
-	return &BoolFlag{BoolFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a Bool value to the flagSet if required
 func (f *BoolFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -212,25 +142,6 @@ func (f *BoolFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceCo
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped BoolFlag.Apply
-func (f *BoolFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-	f.BoolFlag.Apply(set)
-}
-
-// StringFlag is the flag type that wraps *cli.StringFlag to allow
-// for other values to be specified
-type StringFlag struct {
-	*cli.StringFlag
-	set *flag.FlagSet
-}
-
-// NewStringFlag creates a new StringFlag
-func NewStringFlag(flag *cli.StringFlag) *StringFlag {
-	return &StringFlag{StringFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a String value to the flagSet if required
 func (f *StringFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -249,26 +160,6 @@ func (f *StringFlag) ApplyInputSourceValue(context *cli.Context, isc InputSource
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped StringFlag.Apply
-func (f *StringFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-
-	f.StringFlag.Apply(set)
-}
-
-// IntFlag is the flag type that wraps *cli.IntFlag to allow
-// for other values to be specified
-type IntFlag struct {
-	*cli.IntFlag
-	set *flag.FlagSet
-}
-
-// NewIntFlag creates a new IntFlag
-func NewIntFlag(flag *cli.IntFlag) *IntFlag {
-	return &IntFlag{IntFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a int value to the flagSet if required
 func (f *IntFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -287,25 +178,6 @@ func (f *IntFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceCon
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped IntFlag.Apply
-func (f *IntFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-	f.IntFlag.Apply(set)
-}
-
-// DurationFlag is the flag type that wraps *cli.DurationFlag to allow
-// for other values to be specified
-type DurationFlag struct {
-	*cli.DurationFlag
-	set *flag.FlagSet
-}
-
-// NewDurationFlag creates a new DurationFlag
-func NewDurationFlag(flag *cli.DurationFlag) *DurationFlag {
-	return &DurationFlag{DurationFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a Duration value to the flagSet if required
 func (f *DurationFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -324,26 +196,6 @@ func (f *DurationFlag) ApplyInputSourceValue(context *cli.Context, isc InputSour
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped DurationFlag.Apply
-func (f *DurationFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-
-	f.DurationFlag.Apply(set)
-}
-
-// Float64Flag is the flag type that wraps *cli.Float64Flag to allow
-// for other values to be specified
-type Float64Flag struct {
-	*cli.Float64Flag
-	set *flag.FlagSet
-}
-
-// NewFloat64Flag creates a new Float64Flag
-func NewFloat64Flag(flag *cli.Float64Flag) *Float64Flag {
-	return &Float64Flag{Float64Flag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a Float64 value to the flagSet if required
 func (f *Float64Flag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -363,14 +215,6 @@ func (f *Float64Flag) ApplyInputSourceValue(context *cli.Context, isc InputSourc
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped Float64Flag.Apply
-func (f *Float64Flag) Apply(set *flag.FlagSet) {
-	f.set = set
-
-	f.Float64Flag.Apply(set)
-}
-
 func isEnvVarSet(envVars []string) bool {
 	for _, envVar := range envVars {
 		if envVal := os.Getenv(envVar); envVal != "" {

altsrc/flag_generated.go

@@ -0,0 +1,256 @@
+package altsrc
+
+import (
+	"flag"
+
+	"github.com/urfave/cli"
+)
+
+// WARNING: This file is generated!
+
+// BoolFlag is the flag type that wraps cli.BoolFlag to allow
+// for other values to be specified
+type BoolFlag struct {
+	*cli.BoolFlag
+	set *flag.FlagSet
+}
+
+// NewBoolFlag creates a new BoolFlag
+func NewBoolFlag(fl *cli.BoolFlag) *BoolFlag {
+	return &BoolFlag{BoolFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped BoolFlag.Apply
+func (f *BoolFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.BoolFlag.Apply(set)
+}
+
+// DurationFlag is the flag type that wraps cli.DurationFlag to allow
+// for other values to be specified
+type DurationFlag struct {
+	*cli.DurationFlag
+	set *flag.FlagSet
+}
+
+// NewDurationFlag creates a new DurationFlag
+func NewDurationFlag(fl *cli.DurationFlag) *DurationFlag {
+	return &DurationFlag{DurationFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped DurationFlag.Apply
+func (f *DurationFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.DurationFlag.Apply(set)
+}
+
+// Float64Flag is the flag type that wraps cli.Float64Flag to allow
+// for other values to be specified
+type Float64Flag struct {
+	*cli.Float64Flag
+	set *flag.FlagSet
+}
+
+// NewFloat64Flag creates a new Float64Flag
+func NewFloat64Flag(fl *cli.Float64Flag) *Float64Flag {
+	return &Float64Flag{Float64Flag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped Float64Flag.Apply
+func (f *Float64Flag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.Float64Flag.Apply(set)
+}
+
+// GenericFlag is the flag type that wraps cli.GenericFlag to allow
+// for other values to be specified
+type GenericFlag struct {
+	*cli.GenericFlag
+	set *flag.FlagSet
+}
+
+// NewGenericFlag creates a new GenericFlag
+func NewGenericFlag(fl *cli.GenericFlag) *GenericFlag {
+	return &GenericFlag{GenericFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped GenericFlag.Apply
+func (f *GenericFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.GenericFlag.Apply(set)
+}
+
+// Int64Flag is the flag type that wraps cli.Int64Flag to allow
+// for other values to be specified
+type Int64Flag struct {
+	*cli.Int64Flag
+	set *flag.FlagSet
+}
+
+// NewInt64Flag creates a new Int64Flag
+func NewInt64Flag(fl *cli.Int64Flag) *Int64Flag {
+	return &Int64Flag{Int64Flag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped Int64Flag.Apply
+func (f *Int64Flag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.Int64Flag.Apply(set)
+}
+
+// IntFlag is the flag type that wraps cli.IntFlag to allow
+// for other values to be specified
+type IntFlag struct {
+	*cli.IntFlag
+	set *flag.FlagSet
+}
+
+// NewIntFlag creates a new IntFlag
+func NewIntFlag(fl *cli.IntFlag) *IntFlag {
+	return &IntFlag{IntFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped IntFlag.Apply
+func (f *IntFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.IntFlag.Apply(set)
+}
+
+// IntSliceFlag is the flag type that wraps cli.IntSliceFlag to allow
+// for other values to be specified
+type IntSliceFlag struct {
+	*cli.IntSliceFlag
+	set *flag.FlagSet
+}
+
+// NewIntSliceFlag creates a new IntSliceFlag
+func NewIntSliceFlag(fl *cli.IntSliceFlag) *IntSliceFlag {
+	return &IntSliceFlag{IntSliceFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped IntSliceFlag.Apply
+func (f *IntSliceFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.IntSliceFlag.Apply(set)
+}
+
+// Int64SliceFlag is the flag type that wraps cli.Int64SliceFlag to allow
+// for other values to be specified
+type Int64SliceFlag struct {
+	*cli.Int64SliceFlag
+	set *flag.FlagSet
+}
+
+// NewInt64SliceFlag creates a new Int64SliceFlag
+func NewInt64SliceFlag(fl *cli.Int64SliceFlag) *Int64SliceFlag {
+	return &Int64SliceFlag{Int64SliceFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped Int64SliceFlag.Apply
+func (f *Int64SliceFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.Int64SliceFlag.Apply(set)
+}
+
+// Float64SliceFlag is the flag type that wraps cli.Float64SliceFlag to allow
+// for other values to be specified
+type Float64SliceFlag struct {
+	*cli.Float64SliceFlag
+	set *flag.FlagSet
+}
+
+// NewFloat64SliceFlag creates a new Float64SliceFlag
+func NewFloat64SliceFlag(fl *cli.Float64SliceFlag) *Float64SliceFlag {
+	return &Float64SliceFlag{Float64SliceFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped Float64SliceFlag.Apply
+func (f *Float64SliceFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.Float64SliceFlag.Apply(set)
+}
+
+// StringFlag is the flag type that wraps cli.StringFlag to allow
+// for other values to be specified
+type StringFlag struct {
+	*cli.StringFlag
+	set *flag.FlagSet
+}
+
+// NewStringFlag creates a new StringFlag
+func NewStringFlag(fl *cli.StringFlag) *StringFlag {
+	return &StringFlag{StringFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped StringFlag.Apply
+func (f *StringFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.StringFlag.Apply(set)
+}
+
+// StringSliceFlag is the flag type that wraps cli.StringSliceFlag to allow
+// for other values to be specified
+type StringSliceFlag struct {
+	*cli.StringSliceFlag
+	set *flag.FlagSet
+}
+
+// NewStringSliceFlag creates a new StringSliceFlag
+func NewStringSliceFlag(fl *cli.StringSliceFlag) *StringSliceFlag {
+	return &StringSliceFlag{StringSliceFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped StringSliceFlag.Apply
+func (f *StringSliceFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.StringSliceFlag.Apply(set)
+}
+
+// Uint64Flag is the flag type that wraps cli.Uint64Flag to allow
+// for other values to be specified
+type Uint64Flag struct {
+	*cli.Uint64Flag
+	set *flag.FlagSet
+}
+
+// NewUint64Flag creates a new Uint64Flag
+func NewUint64Flag(fl *cli.Uint64Flag) *Uint64Flag {
+	return &Uint64Flag{Uint64Flag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped Uint64Flag.Apply
+func (f *Uint64Flag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.Uint64Flag.Apply(set)
+}
+
+// UintFlag is the flag type that wraps cli.UintFlag to allow
+// for other values to be specified
+type UintFlag struct {
+	*cli.UintFlag
+	set *flag.FlagSet
+}
+
+// NewUintFlag creates a new UintFlag
+func NewUintFlag(fl *cli.UintFlag) *UintFlag {
+	return &UintFlag{UintFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped UintFlag.Apply
+func (f *UintFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.UintFlag.Apply(set)
+}

app.go

@@ -149,6 +149,10 @@ func (a *App) Setup() {
 		a.Categories.AddCommand(command.Category, command)
 	}
 	sort.Sort(a.Categories.(*commandCategories))
+
+	if a.Metadata == nil {
+		a.Metadata = make(map[string]interface{})
+	}
 }
 
 // Run is the entry point to the cli app. Parses the arguments slice and routes

app_test.go

@@ -896,6 +896,7 @@ func TestApp_Run_CommandWithSubcommandHasHelpTopic(t *testing.T) {
 			Name:        "foo",
 			Description: "descriptive wall of text about how it does foo things",
 			Subcommands: []*Command{subCmdBar, subCmdBaz},
+			Action:      func(c *Context) error { return nil },
 		}
 
 		app.Commands = []*Command{cmd}

cli.go

@@ -18,3 +18,5 @@
 //     app.Run(os.Args)
 //   }
 package cli
+
+//go:generate python ./generate-flag-types cli -i flag-types.json -o flag_generated.go

command_test.go

@@ -73,6 +73,55 @@ func TestCommand_Run_DoesNotOverwriteErrorFromBefore(t *testing.T) {
 	}
 }
 
+func TestCommand_Run_BeforeSavesMetadata(t *testing.T) {
+	var receivedMsgFromAction string
+	var receivedMsgFromAfter string
+
+	app := &App{
+		Commands: []*Command{
+			{
+				Name: "bar",
+				Before: func(c *Context) error {
+					c.App.Metadata["msg"] = "hello world"
+					return nil
+				},
+				Action: func(c *Context) error {
+					msg, ok := c.App.Metadata["msg"]
+					if !ok {
+						return errors.New("msg not found")
+					}
+					receivedMsgFromAction = msg.(string)
+					return nil
+				},
+				After: func(c *Context) error {
+					msg, ok := c.App.Metadata["msg"]
+					if !ok {
+						return errors.New("msg not found")
+					}
+					receivedMsgFromAfter = msg.(string)
+					return nil
+				},
+			},
+		},
+	}
+
+	err := app.Run([]string{"foo", "bar"})
+	if err != nil {
+		t.Fatalf("expected no error from Run, got %s", err)
+	}
+
+	expectedMsg := "hello world"
+
+	if receivedMsgFromAction != expectedMsg {
+		t.Fatalf("expected msg from Action to match. Given: %q\nExpected: %q",
+			receivedMsgFromAction, expectedMsg)
+	}
+	if receivedMsgFromAfter != expectedMsg {
+		t.Fatalf("expected msg from After to match. Given: %q\nExpected: %q",
+			receivedMsgFromAction, expectedMsg)
+	}
+}
+
 func TestCommand_OnUsageError_WithWrongFlagValue(t *testing.T) {
 	app := &App{
 		Commands: []*Command{

context.go

@@ -3,9 +3,7 @@ package cli
 import (
 	"errors"
 	"flag"
-	"strconv"
 	"strings"
-	"time"
 )
 
 // Context is a type that is passed through to
@@ -25,117 +23,6 @@ func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context {
 	return &Context{App: app, flagSet: set, parentContext: parentCtx}
 }
 
-// Int looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Int(name string) int {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupInt(name, fs)
-	}
-	return 0
-}
-
-// Int64 looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Int64(name string) int64 {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupInt64(name, fs)
-	}
-	return 0
-}
-
-// Uint looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Uint(name string) uint {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupUint(name, fs)
-	}
-	return 0
-}
-
-// Uint64 looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Uint64(name string) uint64 {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupUint64(name, fs)
-	}
-	return 0
-}
-
-// Duration looks up the value of a local time.Duration flag, returns 0 if no
-// time.Duration flag exists
-func (c *Context) Duration(name string) time.Duration {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupDuration(name, fs)
-	}
-	return 0
-}
-
-// Float64 looks up the value of a local float64 flag, returns 0 if no float64
-// flag exists
-func (c *Context) Float64(name string) float64 {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupFloat64(name, fs)
-	}
-	return 0
-}
-
-// Int64Slice looks up the value of a local int slice flag, returns nil if no int
-// slice flag exists
-func (c *Context) Int64Slice(name string) []int64 {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupInt64Slice(name, fs)
-	}
-	return nil
-}
-
-// Float64Slice looks up the value of a local float64 slice flag, returns nil if no float
-// slice flag exists
-func (c *Context) Float64Slice(name string) []float64 {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupFloat64Slice(name, fs)
-	}
-	return nil
-}
-
-// Bool looks up the value of a local bool flag, returns false if no bool flag exists
-func (c *Context) Bool(name string) bool {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupBool(name, fs)
-	}
-	return false
-}
-
-// String looks up the value of a local string flag, returns "" if no string flag exists
-func (c *Context) String(name string) string {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupString(name, fs)
-	}
-	return ""
-}
-
-// StringSlice looks up the value of a local string slice flag, returns nil if no
-// string slice flag exists
-func (c *Context) StringSlice(name string) []string {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupStringSlice(name, fs)
-	}
-	return nil
-}
-
-// IntSlice looks up the value of a local int slice flag, returns nil if no int
-// slice flag exists
-func (c *Context) IntSlice(name string) []int {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupIntSlice(name, fs)
-	}
-	return nil
-}
-
-// Generic looks up the value of a local generic flag, returns nil if no generic
-// flag exists
-func (c *Context) Generic(name string) interface{} {
-	if fs := lookupFlagSet(name, c); fs != nil {
-		return lookupGeneric(name, fs)
-	}
-	return nil
-}
-
 // NumFlags returns the number of flags set
 func (c *Context) NumFlags() int {
 	return c.flagSet.NFlag()
@@ -210,151 +97,6 @@ func lookupFlagSet(name string, ctx *Context) *flag.FlagSet {
 	return nil
 }
 
-func lookupInt(name string, set *flag.FlagSet) int {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseInt(f.Value.String(), 0, 64)
-		if err != nil {
-			return 0
-		}
-		return int(val)
-	}
-
-	return 0
-}
-
-func lookupInt64(name string, set *flag.FlagSet) int64 {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseInt(f.Value.String(), 0, 64)
-		if err != nil {
-			return 0
-		}
-		return val
-	}
-
-	return 0
-}
-
-func lookupUint(name string, set *flag.FlagSet) uint {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseUint(f.Value.String(), 0, 64)
-		if err != nil {
-			return 0
-		}
-		return uint(val)
-	}
-
-	return 0
-}
-
-func lookupUint64(name string, set *flag.FlagSet) uint64 {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseUint(f.Value.String(), 0, 64)
-		if err != nil {
-			return 0
-		}
-		return val
-	}
-
-	return 0
-}
-
-func lookupDuration(name string, set *flag.FlagSet) time.Duration {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := time.ParseDuration(f.Value.String())
-		if err == nil {
-			return val
-		}
-	}
-
-	return 0
-}
-
-func lookupFloat64(name string, set *flag.FlagSet) float64 {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseFloat(f.Value.String(), 64)
-		if err != nil {
-			return 0
-		}
-		return val
-	}
-
-	return 0
-}
-
-func lookupString(name string, set *flag.FlagSet) string {
-	f := set.Lookup(name)
-	if f != nil {
-		return f.Value.String()
-	}
-
-	return ""
-}
-
-func lookupStringSlice(name string, set *flag.FlagSet) []string {
-	f := set.Lookup(name)
-	if f != nil {
-		return (f.Value.(*StringSlice)).Value()
-
-	}
-
-	return nil
-}
-
-func lookupIntSlice(name string, set *flag.FlagSet) []int {
-	f := set.Lookup(name)
-	if f != nil {
-		return (f.Value.(*IntSlice)).Value()
-
-	}
-
-	return nil
-}
-
-func lookupInt64Slice(name string, set *flag.FlagSet) []int64 {
-	f := set.Lookup(name)
-	if f != nil {
-		return (f.Value.(*Int64Slice)).Value()
-
-	}
-
-	return nil
-}
-
-func lookupFloat64Slice(name string, set *flag.FlagSet) []float64 {
-	f := set.Lookup(name)
-	if f != nil {
-		return (f.Value.(*Float64Slice)).Value()
-	}
-	return nil
-}
-
-func lookupGeneric(name string, set *flag.FlagSet) interface{} {
-	f := set.Lookup(name)
-	if f != nil {
-		return f.Value
-	}
-	return nil
-}
-
-func lookupBool(name string, set *flag.FlagSet) bool {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseBool(f.Value.String())
-		if err != nil {
-			return false
-		}
-		return val
-	}
-
-	return false
-}
-
 func copyFlag(name string, ff *flag.Flag, set *flag.FlagSet) {
 	switch ff.Value.(type) {
 	case Serializeder:

flag-types.json

@@ -0,0 +1,92 @@
+[
+  {
+    "name": "Bool",
+    "type": "bool",
+    "context_default": "false",
+    "parser": "strconv.ParseBool(f.Value.String())"
+  },
+  {
+    "name": "Duration",
+    "type": "time.Duration",
+    "doctail": " (see https://golang.org/pkg/time/#ParseDuration)",
+    "context_default": "0",
+    "parser": "time.ParseDuration(f.Value.String())"
+  },
+  {
+    "name": "Float64",
+    "type": "float64",
+    "context_default": "0",
+    "parser": "strconv.ParseFloat(f.Value.String(), 64)"
+  },
+  {
+    "name": "Generic",
+    "type": "Generic",
+    "dest": false,
+    "context_default": "nil",
+    "context_type": "interface{}"
+  },
+  {
+    "name": "Int64",
+    "type": "int64",
+    "context_default": "0",
+    "parser": "strconv.ParseInt(f.Value.String(), 0, 64)"
+  },
+  {
+    "name": "Int",
+    "type": "int",
+    "context_default": "0",
+    "parser": "strconv.ParseInt(f.Value.String(), 0, 64)",
+    "parser_cast": "int(parsed)"
+  },
+  {
+    "name": "IntSlice",
+    "type": "*IntSlice",
+    "dest": false,
+    "context_default": "nil",
+    "context_type": "[]int",
+    "parser": "(f.Value.(*IntSlice)).Value(), error(nil)"
+  },
+  {
+    "name": "Int64Slice",
+    "type": "*Int64Slice",
+    "dest": false,
+    "context_default": "nil",
+    "context_type": "[]int64",
+    "parser": "(f.Value.(*Int64Slice)).Value(), error(nil)"
+  },
+  {
+    "name": "Float64Slice",
+    "type": "*Float64Slice",
+    "dest": false,
+    "context_default": "nil",
+    "context_type": "[]float64",
+    "parser": "(f.Value.(*Float64Slice)).Value(), error(nil)"
+  },
+  {
+    "name": "String",
+    "type": "string",
+    "context_default": "\"\"",
+    "parser": "f.Value.String(), error(nil)"
+  },
+  {
+    "name": "StringSlice",
+    "type": "*StringSlice",
+    "dest": false,
+    "context_default": "nil",
+    "context_type": "[]string",
+    "parser": "(f.Value.(*StringSlice)).Value(), error(nil)"
+  },
+  {
+    "name": "Uint64",
+    "type": "uint64",
+    "context_default": "0",
+    "parser": "strconv.ParseUint(f.Value.String(), 0, 64)"
+  },
+  {
+    "name": "Uint",
+    "type": "uint",
+    "context_default": "0",
+    "parser": "strconv.ParseUint(f.Value.String(), 0, 64)",
+    "parser_cast": "uint(parsed)"
+  }
+]

flag.go

@@ -77,23 +77,6 @@ type Generic interface {
 	String() string
 }
 
-// GenericFlag is the flag type for types implementing Generic
-type GenericFlag struct {
-	Name    string
-	Aliases []string
-	Value   Generic
-	Usage   string
-	EnvVars []string
-	Hidden  bool
-}
-
-// String returns the string representation of the generic flag to display the
-// help text to the user (uses the String() method of the generic flag to show
-// the value)
-func (f *GenericFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply takes the flagset and calls Set on the generic flag with the value
 // provided by the user for parsing by the flag
 func (f *GenericFlag) Apply(set *flag.FlagSet) {
@@ -112,11 +95,6 @@ func (f *GenericFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of a flag.
-func (f *GenericFlag) Names() []string {
-	return flagNames(f)
-}
-
 // StringSlice wraps a []string to satisfy flag.Value
 type StringSlice struct {
 	slice      []string
@@ -162,22 +140,6 @@ func (f *StringSlice) Value() []string {
 	return f.slice
 }
 
-// StringSliceFlag is a string flag that can be specified multiple times on the
-// command-line
-type StringSliceFlag struct {
-	Name    string
-	Aliases []string
-	Value   *StringSlice
-	Usage   string
-	EnvVars []string
-	Hidden  bool
-}
-
-// String returns the usage
-func (f *StringSliceFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *StringSliceFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -203,11 +165,6 @@ func (f *StringSliceFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of a flag.
-func (f *StringSliceFlag) Names() []string {
-	return flagNames(f)
-}
-
 // IntSlice wraps an []int to satisfy flag.Value
 type IntSlice struct {
 	slice      []int
@@ -273,22 +230,6 @@ func (i *IntSlice) Value() []int {
 	return i.slice
 }
 
-// IntSliceFlag is an int flag that can be specified multiple times on the
-// command-line
-type IntSliceFlag struct {
-	Name    string
-	Aliases []string
-	Value   *IntSlice
-	Usage   string
-	EnvVars []string
-	Hidden  bool
-}
-
-// String returns the usage
-func (f *IntSliceFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *IntSliceFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -317,11 +258,6 @@ func (f *IntSliceFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *IntSliceFlag) Names() []string {
-	return flagNames(f)
-}
-
 // Int64Slice is an opaque type for []int to satisfy flag.Value
 type Int64Slice struct {
 	slice      []int64
@@ -367,22 +303,6 @@ func (f *Int64Slice) Value() []int64 {
 	return f.slice
 }
 
-// Int64SliceFlag is an int flag that can be specified multiple times on the
-// command-line
-type Int64SliceFlag struct {
-	Name    string
-	Aliases []string
-	Value   *Int64Slice
-	Usage   string
-	EnvVars []string
-	Hidden  bool
-}
-
-// String returns the usage
-func (f *Int64SliceFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *Int64SliceFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -411,27 +331,6 @@ func (f *Int64SliceFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of the flag.
-func (f *Int64SliceFlag) Names() []string {
-	return flagNames(f)
-}
-
-// BoolFlag is a switch that defaults to false
-type BoolFlag struct {
-	Name        string
-	Aliases     []string
-	Value       bool
-	Usage       string
-	EnvVars     []string
-	Destination *bool
-	Hidden      bool
-}
-
-// String returns a readable representation of this value (for usage defaults)
-func (f *BoolFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *BoolFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -455,27 +354,6 @@ func (f *BoolFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *BoolFlag) Names() []string {
-	return flagNames(f)
-}
-
-// StringFlag represents a flag that takes as string value
-type StringFlag struct {
-	Name        string
-	Aliases     []string
-	Value       string
-	Usage       string
-	EnvVars     []string
-	Destination *string
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *StringFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *StringFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -496,27 +374,6 @@ func (f *StringFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *StringFlag) Names() []string {
-	return flagNames(f)
-}
-
-// IntFlag is a flag that takes an integer
-type IntFlag struct {
-	Name        string
-	Aliases     []string
-	Value       int
-	Usage       string
-	EnvVars     []string
-	Destination *int
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *IntFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *IntFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -540,27 +397,6 @@ func (f *IntFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *IntFlag) Names() []string {
-	return flagNames(f)
-}
-
-// Int64Flag is a flag that takes a 64-bit integer
-type Int64Flag struct {
-	Name        string
-	Aliases     []string
-	Value       int64
-	Usage       string
-	EnvVars     []string
-	Destination *int64
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *Int64Flag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *Int64Flag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -584,27 +420,6 @@ func (f *Int64Flag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of the flag.
-func (f *Int64Flag) Names() []string {
-	return flagNames(f)
-}
-
-// UintFlag is a flag that takes an unsigned integer
-type UintFlag struct {
-	Name        string
-	Aliases     []string
-	Value       uint
-	Usage       string
-	EnvVars     []string
-	Destination *uint
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *UintFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *UintFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -628,27 +443,6 @@ func (f *UintFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of the flag.
-func (f *UintFlag) Names() []string {
-	return flagNames(f)
-}
-
-// Uint64Flag is a flag that takes an unsigned 64-bit integer
-type Uint64Flag struct {
-	Name        string
-	Aliases     []string
-	Value       uint64
-	Usage       string
-	EnvVars     []string
-	Destination *uint64
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *Uint64Flag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *Uint64Flag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -672,28 +466,6 @@ func (f *Uint64Flag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of the flag.
-func (f *Uint64Flag) Names() []string {
-	return flagNames(f)
-}
-
-// DurationFlag is a flag that takes a duration specified in Go's duration
-// format: https://golang.org/pkg/time/#ParseDuration
-type DurationFlag struct {
-	Name        string
-	Aliases     []string
-	Value       time.Duration
-	Usage       string
-	EnvVars     []string
-	Destination *time.Duration
-	Hidden      bool
-}
-
-// String returns a readable representation of this value (for usage defaults)
-func (f *DurationFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *DurationFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -717,27 +489,6 @@ func (f *DurationFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *DurationFlag) Names() []string {
-	return flagNames(f)
-}
-
-// Float64Flag is a flag that takes an float value
-type Float64Flag struct {
-	Name        string
-	Aliases     []string
-	Value       float64
-	Usage       string
-	EnvVars     []string
-	Destination *float64
-	Hidden      bool
-}
-
-// String returns the usage
-func (f *Float64Flag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *Float64Flag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -760,20 +511,11 @@ func (f *Float64Flag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the name of the flag.
-func (f *Float64Flag) Names() []string {
-	return flagNames(f)
-}
-
-
-
-
 // NewFloat64Slice makes a *Float64Slice with default values
 func NewFloat64Slice(defaults ...float64) *Float64Slice {
 	return &Float64Slice{slice: append([]float64{}, defaults...)}
 }
 
-
 // Float64Slice is an opaque type for []float64 to satisfy flag.Value
 type Float64Slice struct {
 	slice      []float64
@@ -819,22 +561,6 @@ func (f *Float64Slice) Value() []float64 {
 	return f.slice
 }
 
-// Float64SliceFlag is a float64 flag that can be specified multiple times on the
-// command-line
-type Float64SliceFlag struct {
-	Name    string
-	Aliases []string
-	Value   *Float64Slice
-	Usage   string
-	EnvVars []string
-	Hidden  bool
-}
-
-// String returns the usage
-func (f *Float64SliceFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f *Float64SliceFlag) Apply(set *flag.FlagSet) {
 	if f.EnvVars != nil {
@@ -863,13 +589,6 @@ func (f *Float64SliceFlag) Apply(set *flag.FlagSet) {
 	}
 }
 
-// Names returns the names of the flag.
-func (f *Float64SliceFlag) Names() []string {
-	return flagNames(f)
-}
-
-
-
 func visibleFlags(fl []Flag) []Flag {
 	visible := []Flag{}
 	for _, flag := range fl {

flag_generated.go

@@ -0,0 +1,524 @@
+package cli
+
+import (
+	"flag"
+	"strconv"
+	"time"
+)
+
+// WARNING: This file is generated!
+
+// BoolFlag is a flag with type bool
+type BoolFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       bool
+	Destination *bool
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *BoolFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *BoolFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Bool looks up the value of a local BoolFlag, returns
+// false if not found
+func (c *Context) Bool(name string) bool {
+	return lookupBool(name, c.flagSet)
+}
+
+func lookupBool(name string, set *flag.FlagSet) bool {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseBool(f.Value.String())
+		if err != nil {
+			return false
+		}
+		return parsed
+	}
+	return false
+}
+
+// DurationFlag is a flag with type time.Duration (see https://golang.org/pkg/time/#ParseDuration)
+type DurationFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       time.Duration
+	Destination *time.Duration
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *DurationFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *DurationFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Duration looks up the value of a local DurationFlag, returns
+// 0 if not found
+func (c *Context) Duration(name string) time.Duration {
+	return lookupDuration(name, c.flagSet)
+}
+
+func lookupDuration(name string, set *flag.FlagSet) time.Duration {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := time.ParseDuration(f.Value.String())
+		if err != nil {
+			return 0
+		}
+		return parsed
+	}
+	return 0
+}
+
+// Float64Flag is a flag with type float64
+type Float64Flag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       float64
+	Destination *float64
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *Float64Flag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *Float64Flag) Names() []string {
+	return flagNames(f)
+}
+
+// Float64 looks up the value of a local Float64Flag, returns
+// 0 if not found
+func (c *Context) Float64(name string) float64 {
+	return lookupFloat64(name, c.flagSet)
+}
+
+func lookupFloat64(name string, set *flag.FlagSet) float64 {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseFloat(f.Value.String(), 64)
+		if err != nil {
+			return 0
+		}
+		return parsed
+	}
+	return 0
+}
+
+// GenericFlag is a flag with type Generic
+type GenericFlag struct {
+	Name    string
+	Aliases []string
+	Usage   string
+	EnvVars []string
+	Hidden  bool
+	Value   Generic
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *GenericFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *GenericFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Generic looks up the value of a local GenericFlag, returns
+// nil if not found
+func (c *Context) Generic(name string) interface{} {
+	return lookupGeneric(name, c.flagSet)
+}
+
+func lookupGeneric(name string, set *flag.FlagSet) interface{} {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := f.Value, error(nil)
+		if err != nil {
+			return nil
+		}
+		return parsed
+	}
+	return nil
+}
+
+// Int64Flag is a flag with type int64
+type Int64Flag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       int64
+	Destination *int64
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *Int64Flag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *Int64Flag) Names() []string {
+	return flagNames(f)
+}
+
+// Int64 looks up the value of a local Int64Flag, returns
+// 0 if not found
+func (c *Context) Int64(name string) int64 {
+	return lookupInt64(name, c.flagSet)
+}
+
+func lookupInt64(name string, set *flag.FlagSet) int64 {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseInt(f.Value.String(), 0, 64)
+		if err != nil {
+			return 0
+		}
+		return parsed
+	}
+	return 0
+}
+
+// IntFlag is a flag with type int
+type IntFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       int
+	Destination *int
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *IntFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *IntFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Int looks up the value of a local IntFlag, returns
+// 0 if not found
+func (c *Context) Int(name string) int {
+	return lookupInt(name, c.flagSet)
+}
+
+func lookupInt(name string, set *flag.FlagSet) int {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseInt(f.Value.String(), 0, 64)
+		if err != nil {
+			return 0
+		}
+		return int(parsed)
+	}
+	return 0
+}
+
+// IntSliceFlag is a flag with type *IntSlice
+type IntSliceFlag struct {
+	Name    string
+	Aliases []string
+	Usage   string
+	EnvVars []string
+	Hidden  bool
+	Value   *IntSlice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *IntSliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *IntSliceFlag) Names() []string {
+	return flagNames(f)
+}
+
+// IntSlice looks up the value of a local IntSliceFlag, returns
+// nil if not found
+func (c *Context) IntSlice(name string) []int {
+	return lookupIntSlice(name, c.flagSet)
+}
+
+func lookupIntSlice(name string, set *flag.FlagSet) []int {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := (f.Value.(*IntSlice)).Value(), error(nil)
+		if err != nil {
+			return nil
+		}
+		return parsed
+	}
+	return nil
+}
+
+// Int64SliceFlag is a flag with type *Int64Slice
+type Int64SliceFlag struct {
+	Name    string
+	Aliases []string
+	Usage   string
+	EnvVars []string
+	Hidden  bool
+	Value   *Int64Slice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *Int64SliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *Int64SliceFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Int64Slice looks up the value of a local Int64SliceFlag, returns
+// nil if not found
+func (c *Context) Int64Slice(name string) []int64 {
+	return lookupInt64Slice(name, c.flagSet)
+}
+
+func lookupInt64Slice(name string, set *flag.FlagSet) []int64 {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := (f.Value.(*Int64Slice)).Value(), error(nil)
+		if err != nil {
+			return nil
+		}
+		return parsed
+	}
+	return nil
+}
+
+// Float64SliceFlag is a flag with type *Float64Slice
+type Float64SliceFlag struct {
+	Name    string
+	Aliases []string
+	Usage   string
+	EnvVars []string
+	Hidden  bool
+	Value   *Float64Slice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *Float64SliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *Float64SliceFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Float64Slice looks up the value of a local Float64SliceFlag, returns
+// nil if not found
+func (c *Context) Float64Slice(name string) []float64 {
+	return lookupFloat64Slice(name, c.flagSet)
+}
+
+func lookupFloat64Slice(name string, set *flag.FlagSet) []float64 {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := (f.Value.(*Float64Slice)).Value(), error(nil)
+		if err != nil {
+			return nil
+		}
+		return parsed
+	}
+	return nil
+}
+
+// StringFlag is a flag with type string
+type StringFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       string
+	Destination *string
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *StringFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *StringFlag) Names() []string {
+	return flagNames(f)
+}
+
+// String looks up the value of a local StringFlag, returns
+// "" if not found
+func (c *Context) String(name string) string {
+	return lookupString(name, c.flagSet)
+}
+
+func lookupString(name string, set *flag.FlagSet) string {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := f.Value.String(), error(nil)
+		if err != nil {
+			return ""
+		}
+		return parsed
+	}
+	return ""
+}
+
+// StringSliceFlag is a flag with type *StringSlice
+type StringSliceFlag struct {
+	Name    string
+	Aliases []string
+	Usage   string
+	EnvVars []string
+	Hidden  bool
+	Value   *StringSlice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *StringSliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *StringSliceFlag) Names() []string {
+	return flagNames(f)
+}
+
+// StringSlice looks up the value of a local StringSliceFlag, returns
+// nil if not found
+func (c *Context) StringSlice(name string) []string {
+	return lookupStringSlice(name, c.flagSet)
+}
+
+func lookupStringSlice(name string, set *flag.FlagSet) []string {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := (f.Value.(*StringSlice)).Value(), error(nil)
+		if err != nil {
+			return nil
+		}
+		return parsed
+	}
+	return nil
+}
+
+// Uint64Flag is a flag with type uint64
+type Uint64Flag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       uint64
+	Destination *uint64
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *Uint64Flag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *Uint64Flag) Names() []string {
+	return flagNames(f)
+}
+
+// Uint64 looks up the value of a local Uint64Flag, returns
+// 0 if not found
+func (c *Context) Uint64(name string) uint64 {
+	return lookupUint64(name, c.flagSet)
+}
+
+func lookupUint64(name string, set *flag.FlagSet) uint64 {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseUint(f.Value.String(), 0, 64)
+		if err != nil {
+			return 0
+		}
+		return parsed
+	}
+	return 0
+}
+
+// UintFlag is a flag with type uint
+type UintFlag struct {
+	Name        string
+	Aliases     []string
+	Usage       string
+	EnvVars     []string
+	Hidden      bool
+	Value       uint
+	Destination *uint
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f *UintFlag) String() string {
+	return FlagStringer(f)
+}
+
+// Names returns the names of the flag
+func (f *UintFlag) Names() []string {
+	return flagNames(f)
+}
+
+// Uint looks up the value of a local UintFlag, returns
+// 0 if not found
+func (c *Context) Uint(name string) uint {
+	return lookupUint(name, c.flagSet)
+}
+
+func lookupUint(name string, set *flag.FlagSet) uint {
+	f := set.Lookup(name)
+	if f != nil {
+		parsed, err := strconv.ParseUint(f.Value.String(), 0, 64)
+		if err != nil {
+			return 0
+		}
+		return uint(parsed)
+	}
+	return 0
+}

generate-flag-types

@@ -0,0 +1,231 @@
+#!/usr/bin/env python
+"""
+The flag types that ship with the cli library have many things in common, and
+so we can take advantage of the `go generate` command to create much of the
+source code from a list of definitions.  These definitions attempt to cover
+the parts that vary between flag types, and should evolve as needed.
+
+An example of the minimum definition needed is:
+
+    {
+      "name": "SomeType",
+      "type": "sometype",
+      "context_default": "nil"
+    }
+
+In this example, the code generated for the `cli` package will include a type
+named `SomeTypeFlag` that is expected to wrap a value of type `sometype`.
+Fetching values by name via `*cli.Context` will default to a value of `nil`.
+
+A more complete, albeit somewhat redundant, example showing all available
+definition keys is:
+
+    {
+      "name": "VeryMuchType",
+      "type": "*VeryMuchType",
+      "value": true,
+      "dest": false,
+      "doctail": " which really only wraps a []float64, oh well!",
+      "context_type": "[]float64",
+      "context_default": "nil",
+      "parser": "parseVeryMuchType(f.Value.String())",
+      "parser_cast": "[]float64(parsed)"
+    }
+
+The meaning of each field is as follows:
+
+               name (string) - The type "name", which will be suffixed with
+                               `Flag` when generating the type definition
+                               for `cli` and the wrapper type for `altsrc`
+               type (string) - The type that the generated `Flag` type for `cli`
+                               is expected to "contain" as its `.Value` member
+                value (bool) - Should the generated `cli` type have a `Value`
+                               member?
+                 dest (bool) - Should the generated `cli` type support a
+                               destination pointer?
+            doctail (string) - Additional docs for the `cli` flag type comment
+       context_type (string) - The literal type used in the `*cli.Context`
+                               reader func signature
+    context_default (string) - The literal value used as the default by the
+                               `*cli.Context` reader funcs when no value is
+                               present
+             parser (string) - Literal code used to parse the flag `f`,
+                               expected to have a return signature of
+                               (value, error)
+        parser_cast (string) - Literal code used to cast the `parsed` value
+                               returned from the `parser` code
+"""
+
+from __future__ import print_function, unicode_literals
+
+import argparse
+import json
+import os
+import subprocess
+import sys
+import tempfile
+import textwrap
+
+
+class _FancyFormatter(argparse.ArgumentDefaultsHelpFormatter,
+                      argparse.RawDescriptionHelpFormatter):
+    pass
+
+
+def main(sysargs=sys.argv[:]):
+    parser = argparse.ArgumentParser(
+        description='Generate flag type code!',
+        formatter_class=_FancyFormatter)
+    parser.add_argument(
+        'package',
+        type=str, default='cli', choices=_WRITEFUNCS.keys(),
+        help='Package for which flag types will be generated'
+    )
+    parser.add_argument(
+        '-i', '--in-json',
+        type=argparse.FileType('r'),
+        default=sys.stdin,
+        help='Input JSON file which defines each type to be generated'
+    )
+    parser.add_argument(
+        '-o', '--out-go',
+        type=argparse.FileType('w'),
+        default=sys.stdout,
+        help='Output file/stream to which generated source will be written'
+    )
+    parser.epilog = __doc__
+
+    args = parser.parse_args(sysargs[1:])
+    _generate_flag_types(_WRITEFUNCS[args.package], args.out_go, args.in_json)
+    return 0
+
+
+def _generate_flag_types(writefunc, output_go, input_json):
+    types = json.load(input_json)
+
+    tmp = tempfile.NamedTemporaryFile(suffix='.go', delete=False)
+    writefunc(tmp, types)
+    tmp.close()
+
+    new_content = subprocess.check_output(
+        ['goimports', tmp.name]
+    ).decode('utf-8')
+
+    print(new_content, file=output_go, end='')
+    output_go.flush()
+    os.remove(tmp.name)
+
+
+def _set_typedef_defaults(typedef):
+    typedef.setdefault('doctail', '')
+    typedef.setdefault('context_type', typedef['type'])
+    typedef.setdefault('dest', True)
+    typedef.setdefault('parser', 'f.Value, error(nil)')
+    typedef.setdefault('parser_cast', 'parsed')
+
+
+def _write_cli_flag_types(outfile, types):
+    _fwrite(outfile, """\
+        package cli
+
+        // WARNING: This file is generated!
+
+        """)
+
+    for typedef in types:
+        _set_typedef_defaults(typedef)
+
+        _fwrite(outfile, """\
+        // {name}Flag is a flag with type {type}{doctail}
+        type {name}Flag struct {{
+            Name string
+            Aliases []string
+            Usage string
+            EnvVars []string
+            Hidden bool
+            Value {type}
+        """.format(**typedef))
+
+        if typedef['dest']:
+            _fwrite(outfile, """\
+            Destination *{type}
+            """.format(**typedef))
+
+        _fwrite(outfile, "\n}\n\n")
+
+        _fwrite(outfile, """\
+            // String returns a readable representation of this value
+            // (for usage defaults)
+            func (f *{name}Flag) String() string {{
+                return FlagStringer(f)
+            }}
+
+            // Names returns the names of the flag
+            func (f *{name}Flag) Names() []string {{
+                return flagNames(f)
+            }}
+
+            // {name} looks up the value of a local {name}Flag, returns
+            // {context_default} if not found
+            func (c *Context) {name}(name string) {context_type} {{
+                return lookup{name}(name, c.flagSet)
+            }}
+
+            func lookup{name}(name string, set *flag.FlagSet) {context_type} {{
+                f := set.Lookup(name)
+                if f != nil {{
+                    parsed, err := {parser}
+                    if err != nil {{
+                        return {context_default}
+                    }}
+                    return {parser_cast}
+                }}
+                return {context_default}
+            }}
+            """.format(**typedef))
+
+
+def _write_altsrc_flag_types(outfile, types):
+    _fwrite(outfile, """\
+        package altsrc
+
+        // WARNING: This file is generated!
+
+        """)
+
+    for typedef in types:
+        _set_typedef_defaults(typedef)
+
+        _fwrite(outfile, """\
+        // {name}Flag is the flag type that wraps cli.{name}Flag to allow
+        // for other values to be specified
+        type {name}Flag struct {{
+            *cli.{name}Flag
+            set *flag.FlagSet
+        }}
+
+        // New{name}Flag creates a new {name}Flag
+        func New{name}Flag(fl *cli.{name}Flag) *{name}Flag {{
+            return &{name}Flag{{{name}Flag: fl, set: nil}}
+        }}
+
+        // Apply saves the flagSet for later usage calls, then calls the
+        // wrapped {name}Flag.Apply
+        func (f *{name}Flag) Apply(set *flag.FlagSet) {{
+            f.set = set
+            f.{name}Flag.Apply(set)
+        }}
+        """.format(**typedef))
+
+
+def _fwrite(outfile, text):
+    print(textwrap.dedent(text), end='', file=outfile)
+
+
+_WRITEFUNCS = {
+    'cli': _write_cli_flag_types,
+    'altsrc': _write_altsrc_flag_types
+}
+
+if __name__ == '__main__':
+    sys.exit(main())

runtests

@@ -38,7 +38,7 @@ def _target(func):
 @_target
 def _test():
     if check_output('go version'.split()).split()[2] < 'go1.2':
-        _run('go test -v .'.split())
+        _run('go test -v .')
         return
 
     coverprofiles = []
@@ -55,7 +55,7 @@ def _test():
         ])
 
     combined_name = _combine_coverprofiles(coverprofiles)
-    _run('go tool cover -func={}'.format(combined_name).split())
+    _run('go tool cover -func={}'.format(combined_name))
     os.remove(combined_name)
 
 
@@ -66,7 +66,7 @@ def _gfmxr():
 
 @_target
 def _vet():
-    _run('go vet ./...'.split())
+    _run('go vet ./...')
 
 
 @_target
@@ -101,10 +101,23 @@ def _toc():
         os.path.join('node_modules', '.bin', 'markdown-toc'),
         '-i', 'README.md'
     ])
-    _run(['git', 'diff', '--quiet'])
+    _run('git diff --exit-code')
+
+
+@_target
+def _gen():
+    go_version = check_output('go version'.split()).split()[2]
+    if go_version < 'go1.4':
+        print('runtests: skip on {}'.format(go_version), file=sys.stderr)
+        return
+
+    _run('go generate ./...')
+    _run('git diff --exit-code')
 
 
 def _run(command):
+    if hasattr(command, 'split'):
+        command = command.split()
     print('runtests: {}'.format(' '.join(command)), file=sys.stderr)
     sys.stderr.flush()
     check_call(command)