Merge pull request #297 from ston1th/master

Added destination scan support for flags

README.md

@@ -158,6 +158,32 @@ app.Action = func(c *cli.Context) {
 ...
 ```
 
+You can also set a destination variable for a flag, to which the content will be scanned.
+``` go
+...
+var language string
+app.Flags = []cli.Flag {
+  cli.StringFlag{
+    Name:        "lang",
+    Value:       "english",
+    Usage:       "language for the greeting",
+    Destination: &language,
+  },
+}
+app.Action = func(c *cli.Context) {
+  name := "someone"
+  if len(c.Args()) > 0 {
+    name = c.Args()[0]
+  }
+  if language == "spanish" {
+    println("Hola", name)
+  } else {
+    println("Hello", name)
+  }
+}
+...
+```
+
 See full list of flags at http://godoc.org/github.com/codegangsta/cli
 
 #### Alternate Names

flag.go

@@ -240,6 +240,7 @@ type BoolFlag struct {
 	Name        string
 	Usage       string
 	EnvVar      string
+	Destination *bool
 }
 
 // String returns a readable representation of this value (for usage defaults)
@@ -264,6 +265,10 @@ func (f BoolFlag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.BoolVar(f.Destination, name, val, f.Usage)
+			return
+		}
 		set.Bool(name, val, f.Usage)
 	})
 }
@@ -278,6 +283,7 @@ type BoolTFlag struct {
 	Name        string
 	Usage       string
 	EnvVar      string
+	Destination *bool
 }
 
 // String returns a readable representation of this value (for usage defaults)
@@ -302,6 +308,10 @@ func (f BoolTFlag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.BoolVar(f.Destination, name, val, f.Usage)
+			return
+		}
 		set.Bool(name, val, f.Usage)
 	})
 }
@@ -316,6 +326,7 @@ type StringFlag struct {
 	Value       string
 	Usage       string
 	EnvVar      string
+	Destination *string
 }
 
 // String returns the usage
@@ -345,6 +356,10 @@ func (f StringFlag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.StringVar(f.Destination, name, f.Value, f.Usage)
+			return
+		}
 		set.String(name, f.Value, f.Usage)
 	})
 }
@@ -360,6 +375,7 @@ type IntFlag struct {
 	Value       int
 	Usage       string
 	EnvVar      string
+	Destination *int
 }
 
 // String returns the usage
@@ -383,6 +399,10 @@ func (f IntFlag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.IntVar(f.Destination, name, f.Value, f.Usage)
+			return
+		}
 		set.Int(name, f.Value, f.Usage)
 	})
 }
@@ -398,6 +418,7 @@ type DurationFlag struct {
 	Value       time.Duration
 	Usage       string
 	EnvVar      string
+	Destination *time.Duration
 }
 
 // String returns a readable representation of this value (for usage defaults)
@@ -421,6 +442,10 @@ func (f DurationFlag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.DurationVar(f.Destination, name, f.Value, f.Usage)
+			return
+		}
 		set.Duration(name, f.Value, f.Usage)
 	})
 }
@@ -436,6 +461,7 @@ type Float64Flag struct {
 	Value       float64
 	Usage       string
 	EnvVar      string
+	Destination *float64
 }
 
 // String returns the usage
@@ -458,6 +484,10 @@ func (f Float64Flag) Apply(set *flag.FlagSet) {
 	}
 
 	eachName(f.Name, func(name string) {
+		if f.Destination != nil {
+			set.Float64Var(f.Destination, name, f.Value, f.Usage)
+			return
+		}
 		set.Float64(name, f.Value, f.Usage)
 	})
 }

flag_test.go

@@ -305,6 +305,24 @@ func TestParseMultiString(t *testing.T) {
 	}).Run([]string{"run", "-s", "10"})
 }
 
+func TestParseDestinationString(t *testing.T) {
+	var dest string
+	a := App{
+		Flags: []Flag{
+			StringFlag{
+				Name:        "dest",
+				Destination: &dest,
+			},
+		},
+		Action: func(ctx *Context) {
+			if dest != "10" {
+				t.Errorf("expected destination String 10")
+			}
+		},
+	}
+	a.Run([]string{"run", "--dest", "10"})
+}
+
 func TestParseMultiStringFromEnv(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("APP_COUNT", "20")
@@ -412,6 +430,24 @@ func TestParseMultiInt(t *testing.T) {
 	a.Run([]string{"run", "-s", "10"})
 }
 
+func TestParseDestinationInt(t *testing.T) {
+	var dest int
+	a := App{
+		Flags: []Flag{
+			IntFlag{
+				Name:        "dest",
+				Destination: &dest,
+			},
+		},
+		Action: func(ctx *Context) {
+			if dest != 10 {
+				t.Errorf("expected destination Int 10")
+			}
+		},
+	}
+	a.Run([]string{"run", "--dest", "10"})
+}
+
 func TestParseMultiIntFromEnv(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("APP_TIMEOUT_SECONDS", "10")
@@ -521,6 +557,24 @@ func TestParseMultiFloat64(t *testing.T) {
 	a.Run([]string{"run", "-s", "10.2"})
 }
 
+func TestParseDestinationFloat64(t *testing.T) {
+	var dest float64
+	a := App{
+		Flags: []Flag{
+			Float64Flag{
+				Name:        "dest",
+				Destination: &dest,
+			},
+		},
+		Action: func(ctx *Context) {
+			if dest != 10.2 {
+				t.Errorf("expected destination Float64 10.2")
+			}
+		},
+	}
+	a.Run([]string{"run", "--dest", "10.2"})
+}
+
 func TestParseMultiFloat64FromEnv(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("APP_TIMEOUT_SECONDS", "15.5")
@@ -576,6 +630,24 @@ func TestParseMultiBool(t *testing.T) {
 	a.Run([]string{"run", "--serve"})
 }
 
+func TestParseDestinationBool(t *testing.T) {
+	var dest bool
+	a := App{
+		Flags: []Flag{
+			BoolFlag{
+				Name:        "dest",
+				Destination: &dest,
+			},
+		},
+		Action: func(ctx *Context) {
+			if dest != true {
+				t.Errorf("expected destination Bool true")
+			}
+		},
+	}
+	a.Run([]string{"run", "--dest"})
+}
+
 func TestParseMultiBoolFromEnv(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("APP_DEBUG", "1")
@@ -631,6 +703,24 @@ func TestParseMultiBoolT(t *testing.T) {
 	a.Run([]string{"run", "--serve"})
 }
 
+func TestParseDestinationBoolT(t *testing.T) {
+	var dest bool
+	a := App{
+		Flags: []Flag{
+			BoolTFlag{
+				Name:        "dest",
+				Destination: &dest,
+			},
+		},
+		Action: func(ctx *Context) {
+			if dest != true {
+				t.Errorf("expected destination BoolT true")
+			}
+		},
+	}
+	a.Run([]string{"run", "--dest"})
+}
+
 func TestParseMultiBoolTFromEnv(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("APP_DEBUG", "0")