Merge pull request #466 from urfave/flag-context-gen

Generate code for flag types and context accessors

.travis.yml

@@ -23,11 +23,13 @@ matrix:
 
 before_script:
 - 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
 
 script:
+- ./runtests gen
 - ./runtests vet
 - ./runtests test
 - ./runtests gfmxr

CHANGELOG.md

@@ -3,6 +3,9 @@
 **ATTN**: This project uses [semantic versioning](http://semver.org/).
 
 ## [Unreleased]
+### Added
+- Flag type code generation via `go generate`
+
 ### Changed
 - Raise minimum tested/supported Go version to 1.2+
 

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"
@@ -63,18 +62,6 @@ 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 {
@@ -94,25 +81,6 @@ 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 {
@@ -135,25 +103,6 @@ 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 {
@@ -176,25 +125,6 @@ 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 {
@@ -213,25 +143,6 @@ 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)
-}
-
-// BoolTFlag is the flag type that wraps cli.BoolTFlag to allow
-// for other values to be specified
-type BoolTFlag struct {
-	cli.BoolTFlag
-	set *flag.FlagSet
-}
-
-// NewBoolTFlag creates a new BoolTFlag
-func NewBoolTFlag(flag cli.BoolTFlag) *BoolTFlag {
-	return &BoolTFlag{BoolTFlag: flag, set: nil}
-}
-
 // ApplyInputSourceValue applies a BoolT value to the flagSet if required
 func (f *BoolTFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceContext) error {
 	if f.set != nil {
@@ -250,26 +161,6 @@ func (f *BoolTFlag) ApplyInputSourceValue(context *cli.Context, isc InputSourceC
 	return nil
 }
 
-// Apply saves the flagSet for later usage then calls
-// the wrapped BoolTFlag.Apply
-func (f *BoolTFlag) Apply(set *flag.FlagSet) {
-	f.set = set
-
-	f.BoolTFlag.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 {
@@ -288,26 +179,6 @@ 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 {
@@ -326,25 +197,6 @@ 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 {
@@ -363,26 +215,6 @@ 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 {
@@ -402,14 +234,6 @@ 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 strings.Split(envVars, ",") {
 		envVar = strings.TrimSpace(envVar)

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)
+}
+
+// BoolTFlag is the flag type that wraps cli.BoolTFlag to allow
+// for other values to be specified
+type BoolTFlag struct {
+	cli.BoolTFlag
+	set *flag.FlagSet
+}
+
+// NewBoolTFlag creates a new BoolTFlag
+func NewBoolTFlag(fl cli.BoolTFlag) *BoolTFlag {
+	return &BoolTFlag{BoolTFlag: fl, set: nil}
+}
+
+// Apply saves the flagSet for later usage calls, then calls the
+// wrapped BoolTFlag.Apply
+func (f *BoolTFlag) Apply(set *flag.FlagSet) {
+	f.set = set
+	f.BoolTFlag.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)
+}
+
+// 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)
+}

cli.go

@@ -17,3 +17,5 @@
 //     app.Run(os.Args)
 //   }
 package cli
+
+//go:generate python ./generate-flag-types cli -i flag-types.json -o flag_generated.go

context.go

@@ -3,9 +3,7 @@ package cli
 import (
 	"errors"
 	"flag"
-	"strconv"
 	"strings"
-	"time"
 )
 
 // Context is a type that is passed through to
@@ -26,190 +24,6 @@ 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 {
-	return lookupInt(name, c.flagSet)
-}
-
-// Int64 looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Int64(name string) int64 {
-	return lookupInt64(name, c.flagSet)
-}
-
-// Uint looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Uint(name string) uint {
-	return lookupUint(name, c.flagSet)
-}
-
-// Uint64 looks up the value of a local int flag, returns 0 if no int flag exists
-func (c *Context) Uint64(name string) uint64 {
-	return lookupUint64(name, c.flagSet)
-}
-
-// 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 {
-	return lookupDuration(name, c.flagSet)
-}
-
-// Float64 looks up the value of a local float64 flag, returns 0 if no float64
-// flag exists
-func (c *Context) Float64(name string) float64 {
-	return lookupFloat64(name, c.flagSet)
-}
-
-// Bool looks up the value of a local bool flag, returns false if no bool flag exists
-func (c *Context) Bool(name string) bool {
-	return lookupBool(name, c.flagSet)
-}
-
-// BoolT looks up the value of a local boolT flag, returns false if no bool flag exists
-func (c *Context) BoolT(name string) bool {
-	return lookupBoolT(name, c.flagSet)
-}
-
-// String looks up the value of a local string flag, returns "" if no string flag exists
-func (c *Context) String(name string) string {
-	return lookupString(name, c.flagSet)
-}
-
-// 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 {
-	return lookupStringSlice(name, c.flagSet)
-}
-
-// 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 {
-	return lookupIntSlice(name, c.flagSet)
-}
-
-// 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 {
-	return lookupInt64Slice(name, c.flagSet)
-}
-
-// Generic looks up the value of a local generic flag, returns nil if no generic
-// flag exists
-func (c *Context) Generic(name string) interface{} {
-	return lookupGeneric(name, c.flagSet)
-}
-
-// GlobalInt looks up the value of a global int flag, returns 0 if no int flag exists
-func (c *Context) GlobalInt(name string) int {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupInt(name, fs)
-	}
-	return 0
-}
-
-// GlobalInt64 looks up the value of a global int flag, returns 0 if no int flag exists
-func (c *Context) GlobalInt64(name string) int64 {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupInt64(name, fs)
-	}
-	return 0
-}
-
-// GlobalUint looks up the value of a global int flag, returns 0 if no int flag exists
-func (c *Context) GlobalUint(name string) uint {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupUint(name, fs)
-	}
-	return 0
-}
-
-// GlobalUint64 looks up the value of a global int flag, returns 0 if no int flag exists
-func (c *Context) GlobalUint64(name string) uint64 {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupUint64(name, fs)
-	}
-	return 0
-}
-
-// GlobalFloat64 looks up the value of a global float64 flag, returns float64(0)
-// if no float64 flag exists
-func (c *Context) GlobalFloat64(name string) float64 {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupFloat64(name, fs)
-	}
-	return float64(0)
-}
-
-// GlobalDuration looks up the value of a global time.Duration flag, returns 0
-// if no time.Duration flag exists
-func (c *Context) GlobalDuration(name string) time.Duration {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupDuration(name, fs)
-	}
-	return 0
-}
-
-// GlobalBool looks up the value of a global bool flag, returns false if no bool
-// flag exists
-func (c *Context) GlobalBool(name string) bool {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupBool(name, fs)
-	}
-	return false
-}
-
-// GlobalBoolT looks up the value of a global bool flag, returns true if no bool
-// flag exists
-func (c *Context) GlobalBoolT(name string) bool {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupBoolT(name, fs)
-	}
-	return false
-}
-
-// GlobalString looks up the value of a global string flag, returns "" if no
-// string flag exists
-func (c *Context) GlobalString(name string) string {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupString(name, fs)
-	}
-	return ""
-}
-
-// GlobalStringSlice looks up the value of a global string slice flag, returns
-// nil if no string slice flag exists
-func (c *Context) GlobalStringSlice(name string) []string {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupStringSlice(name, fs)
-	}
-	return nil
-}
-
-// GlobalIntSlice looks up the value of a global int slice flag, returns nil if
-// no int slice flag exists
-func (c *Context) GlobalIntSlice(name string) []int {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupIntSlice(name, fs)
-	}
-	return nil
-}
-
-// GlobalInt64Slice looks up the value of a global int slice flag, returns nil if
-// no int slice flag exists
-func (c *Context) GlobalInt64Slice(name string) []int64 {
-	if fs := lookupGlobalFlagSet(name, c); fs != nil {
-		return lookupInt64Slice(name, fs)
-	}
-	return nil
-}
-
-// GlobalGeneric looks up the value of a global generic flag, returns nil if no
-// generic flag exists
-func (c *Context) GlobalGeneric(name string) interface{} {
-	if fs := lookupGlobalFlagSet(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()
@@ -357,156 +171,6 @@ func lookupGlobalFlagSet(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 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 lookupBoolT(name string, set *flag.FlagSet) bool {
-	f := set.Lookup(name)
-	if f != nil {
-		val, err := strconv.ParseBool(f.Value.String())
-		if err != nil {
-			return true
-		}
-		return val
-	}
-
-	return false
-}
-
 func copyFlag(name string, ff *flag.Flag, set *flag.FlagSet) {
 	switch ff.Value.(type) {
 	case *StringSlice:

flag-types.json

@@ -0,0 +1,93 @@
+[
+  {
+    "name": "Bool",
+    "type": "bool",
+    "value": false,
+    "context_default": "false",
+    "parser": "strconv.ParseBool(f.Value.String())"
+  },
+  {
+    "name": "BoolT",
+    "type": "bool",
+    "value": false,
+    "doctail": " that is true by default",
+    "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": "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

@@ -70,22 +70,6 @@ type Generic interface {
 	String() string
 }
 
-// GenericFlag is the flag type for types implementing Generic
-type GenericFlag struct {
-	Name   string
-	Value  Generic
-	Usage  string
-	EnvVar 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) {
@@ -105,11 +89,6 @@ func (f GenericFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of a flag.
-func (f GenericFlag) GetName() string {
-	return f.Name
-}
-
 // StringSlice is an opaque type for []string to satisfy flag.Value
 type StringSlice []string
 
@@ -129,21 +108,6 @@ func (f *StringSlice) Value() []string {
 	return *f
 }
 
-// StringSliceFlag is a string flag that can be specified multiple times on the
-// command-line
-type StringSliceFlag struct {
-	Name   string
-	Value  *StringSlice
-	Usage  string
-	EnvVar 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.EnvVar != "" {
@@ -169,11 +133,6 @@ func (f StringSliceFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of a flag.
-func (f StringSliceFlag) GetName() string {
-	return f.Name
-}
-
 // IntSlice is an opaque type for []int to satisfy flag.Value
 type IntSlice []int
 
@@ -197,21 +156,6 @@ func (f *IntSlice) Value() []int {
 	return *f
 }
 
-// IntSliceFlag is an int flag that can be specified multiple times on the
-// command-line
-type IntSliceFlag struct {
-	Name   string
-	Value  *IntSlice
-	Usage  string
-	EnvVar 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.EnvVar != "" {
@@ -240,11 +184,6 @@ func (f IntSliceFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f IntSliceFlag) GetName() string {
-	return f.Name
-}
-
 // Int64Slice is an opaque type for []int to satisfy flag.Value
 type Int64Slice []int64
 
@@ -268,21 +207,6 @@ func (f *Int64Slice) Value() []int64 {
 	return *f
 }
 
-// Int64SliceFlag is an int flag that can be specified multiple times on the
-// command-line
-type Int64SliceFlag struct {
-	Name   string
-	Value  *Int64Slice
-	Usage  string
-	EnvVar 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.EnvVar != "" {
@@ -311,25 +235,6 @@ func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f Int64SliceFlag) GetName() string {
-	return f.Name
-}
-
-// BoolFlag is a switch that defaults to false
-type BoolFlag struct {
-	Name        string
-	Usage       string
-	EnvVar      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) {
 	val := false
@@ -355,26 +260,6 @@ func (f BoolFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f BoolFlag) GetName() string {
-	return f.Name
-}
-
-// BoolTFlag this represents a boolean flag that is true by default, but can
-// still be set to false by --some-flag=false
-type BoolTFlag struct {
-	Name        string
-	Usage       string
-	EnvVar      string
-	Destination *bool
-	Hidden      bool
-}
-
-// String returns a readable representation of this value (for usage defaults)
-func (f BoolTFlag) String() string {
-	return FlagStringer(f)
-}
-
 // Apply populates the flag given the flag set and environment
 func (f BoolTFlag) Apply(set *flag.FlagSet) {
 	val := true
@@ -400,26 +285,6 @@ func (f BoolTFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f BoolTFlag) GetName() string {
-	return f.Name
-}
-
-// StringFlag represents a flag that takes as string value
-type StringFlag struct {
-	Name        string
-	Value       string
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -441,26 +306,6 @@ func (f StringFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f StringFlag) GetName() string {
-	return f.Name
-}
-
-// IntFlag is a flag that takes an integer
-type IntFlag struct {
-	Name        string
-	Value       int
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -485,26 +330,6 @@ func (f IntFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f IntFlag) GetName() string {
-	return f.Name
-}
-
-// Int64Flag is a flag that takes a 64-bit integer
-type Int64Flag struct {
-	Name        string
-	Value       int64
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -529,26 +354,6 @@ func (f Int64Flag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f Int64Flag) GetName() string {
-	return f.Name
-}
-
-// UintFlag is a flag that takes an unsigned integer
-type UintFlag struct {
-	Name        string
-	Value       uint
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -573,26 +378,6 @@ func (f UintFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f UintFlag) GetName() string {
-	return f.Name
-}
-
-// Uint64Flag is a flag that takes an unsigned 64-bit integer
-type Uint64Flag struct {
-	Name        string
-	Value       uint64
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -617,27 +402,6 @@ func (f Uint64Flag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f Uint64Flag) GetName() string {
-	return f.Name
-}
-
-// 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
-	Value       time.Duration
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -662,26 +426,6 @@ func (f DurationFlag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f DurationFlag) GetName() string {
-	return f.Name
-}
-
-// Float64Flag is a flag that takes an float value
-type Float64Flag struct {
-	Name        string
-	Value       float64
-	Usage       string
-	EnvVar      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.EnvVar != "" {
@@ -705,11 +449,6 @@ func (f Float64Flag) Apply(set *flag.FlagSet) {
 	})
 }
 
-// GetName returns the name of the flag.
-func (f Float64Flag) GetName() string {
-	return f.Name
-}
-
 func visibleFlags(fl []Flag) []Flag {
 	visible := []Flag{}
 	for _, flag := range fl {

flag_generated.go

@@ -0,0 +1,627 @@
+package cli
+
+import (
+	"flag"
+	"strconv"
+	"time"
+)
+
+// WARNING: This file is generated!
+
+// BoolFlag is a flag with type bool
+type BoolFlag struct {
+	Name        string
+	Usage       string
+	EnvVar      string
+	Hidden      bool
+	Destination *bool
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f BoolFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f BoolFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalBool looks up the value of a global BoolFlag, returns
+// false if not found
+func (c *Context) GlobalBool(name string) bool {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupBool(name, fs)
+	}
+	return false
+}
+
+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
+}
+
+// BoolTFlag is a flag with type bool that is true by default
+type BoolTFlag struct {
+	Name        string
+	Usage       string
+	EnvVar      string
+	Hidden      bool
+	Destination *bool
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f BoolTFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f BoolTFlag) GetName() string {
+	return f.Name
+}
+
+// BoolT looks up the value of a local BoolTFlag, returns
+// false if not found
+func (c *Context) BoolT(name string) bool {
+	return lookupBoolT(name, c.flagSet)
+}
+
+// GlobalBoolT looks up the value of a global BoolTFlag, returns
+// false if not found
+func (c *Context) GlobalBoolT(name string) bool {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupBoolT(name, fs)
+	}
+	return false
+}
+
+func lookupBoolT(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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f DurationFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalDuration looks up the value of a global DurationFlag, returns
+// 0 if not found
+func (c *Context) GlobalDuration(name string) time.Duration {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupDuration(name, fs)
+	}
+	return 0
+}
+
+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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f Float64Flag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalFloat64 looks up the value of a global Float64Flag, returns
+// 0 if not found
+func (c *Context) GlobalFloat64(name string) float64 {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupFloat64(name, fs)
+	}
+	return 0
+}
+
+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
+	Usage  string
+	EnvVar string
+	Hidden bool
+	Value  Generic
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f GenericFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f GenericFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalGeneric looks up the value of a global GenericFlag, returns
+// nil if not found
+func (c *Context) GlobalGeneric(name string) interface{} {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupGeneric(name, fs)
+	}
+	return nil
+}
+
+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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f Int64Flag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalInt64 looks up the value of a global Int64Flag, returns
+// 0 if not found
+func (c *Context) GlobalInt64(name string) int64 {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupInt64(name, fs)
+	}
+	return 0
+}
+
+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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f IntFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalInt looks up the value of a global IntFlag, returns
+// 0 if not found
+func (c *Context) GlobalInt(name string) int {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupInt(name, fs)
+	}
+	return 0
+}
+
+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
+	Usage  string
+	EnvVar string
+	Hidden bool
+	Value  *IntSlice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f IntSliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f IntSliceFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalIntSlice looks up the value of a global IntSliceFlag, returns
+// nil if not found
+func (c *Context) GlobalIntSlice(name string) []int {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupIntSlice(name, fs)
+	}
+	return nil
+}
+
+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
+	Usage  string
+	EnvVar string
+	Hidden bool
+	Value  *Int64Slice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f Int64SliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f Int64SliceFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalInt64Slice looks up the value of a global Int64SliceFlag, returns
+// nil if not found
+func (c *Context) GlobalInt64Slice(name string) []int64 {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupInt64Slice(name, fs)
+	}
+	return nil
+}
+
+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
+}
+
+// StringFlag is a flag with type string
+type StringFlag struct {
+	Name        string
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f StringFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalString looks up the value of a global StringFlag, returns
+// "" if not found
+func (c *Context) GlobalString(name string) string {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupString(name, fs)
+	}
+	return ""
+}
+
+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
+	Usage  string
+	EnvVar string
+	Hidden bool
+	Value  *StringSlice
+}
+
+// String returns a readable representation of this value
+// (for usage defaults)
+func (f StringSliceFlag) String() string {
+	return FlagStringer(f)
+}
+
+// GetName returns the name of the flag
+func (f StringSliceFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalStringSlice looks up the value of a global StringSliceFlag, returns
+// nil if not found
+func (c *Context) GlobalStringSlice(name string) []string {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupStringSlice(name, fs)
+	}
+	return nil
+}
+
+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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f Uint64Flag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalUint64 looks up the value of a global Uint64Flag, returns
+// 0 if not found
+func (c *Context) GlobalUint64(name string) uint64 {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupUint64(name, fs)
+	}
+	return 0
+}
+
+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
+	Usage       string
+	EnvVar      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)
+}
+
+// GetName returns the name of the flag
+func (f UintFlag) GetName() string {
+	return f.Name
+}
+
+// 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)
+}
+
+// GlobalUint looks up the value of a global UintFlag, returns
+// 0 if not found
+func (c *Context) GlobalUint(name string) uint {
+	if fs := lookupGlobalFlagSet(name, c); fs != nil {
+		return lookupUint(name, fs)
+	}
+	return 0
+}
+
+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 +1,244 @@
+#!/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('value', 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
+            Usage string
+            EnvVar string
+            Hidden bool
+        """.format(**typedef))
+
+        if typedef['value']:
+            _fwrite(outfile, """\
+            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)
+            }}
+
+            // GetName returns the name of the flag
+            func (f {name}Flag) GetName() string {{
+                return f.Name
+            }}
+
+            // {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)
+            }}
+
+            // Global{name} looks up the value of a global {name}Flag, returns
+            // {context_default} if not found
+            func (c *Context) Global{name}(name string) {context_type} {{
+                if fs := lookupGlobalFlagSet(name, c); fs != nil {{
+                    return lookup{name}(name, fs)
+                }}
+                return {context_default}
+            }}
+
+            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

@@ -20,6 +20,7 @@ def main(sysargs=sys.argv[:]):
         'test': _test,
         'gfmxr': _gfmxr,
         'toc': _toc,
+        'gen': _gen,
     }
 
     parser = argparse.ArgumentParser()
@@ -34,7 +35,7 @@ def main(sysargs=sys.argv[:]):
 
 def _test():
     if check_output('go version'.split()).split()[2] < 'go1.2':
-        _run('go test -v .'.split())
+        _run('go test -v .')
         return
 
     coverprofiles = []
@@ -51,7 +52,7 @@ 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)
 
 
@@ -60,15 +61,27 @@ def _gfmxr():
 
 
 def _vet():
-    _run('go vet ./...'.split())
+    _run('go vet ./...')
 
 
 def _toc():
-    _run(['node_modules/.bin/markdown-toc', '-i', 'README.md'])
+    _run('node_modules/.bin/markdown-toc -i README.md')
-    _run(['git', 'diff', '--quiet'])
+    _run('git diff --exit-code')
+
+
+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)
     check_call(command)