Non-blocking version of GetSingleKey()

README.md

@@ -45,3 +45,36 @@ func main() {
 	}	
 }
 ```
+
+Example of getting keystrokes in a non-blocking loop:
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/eiannoe/keyboard"
+)
+
+func main() {
+	err := keyboard.Open()
+	if err != nil {
+		panic(err)
+	}
+	defer keyboard.Close()
+
+	fmt.Println("Press ESC to quit")
+	fmt.Println("Starting loop...")
+	for {
+		char, key, err := keyboard.GetKey()
+		if (err != nil) {
+			panic(err)
+		} else if (key == keyboard.KeyEsc) {
+			fmt.Println("Exiting loop!")
+			break
+		}
+		fmt.Printf("You pressed: %q\r\n", char)
+		time.Sleep(time.Second * 1)
+		fmt.Println("Continuing loop...")
+	}	
+}
+```

keyboard_common.go

@@ -1,143 +1,169 @@
 package keyboard
 
 type (
-    Key        uint16
+	Key uint16
 
-    keyEvent struct {
-        key    Key       // One of Key* constants, invalid if 'Ch' is not 0
-        rune   rune      // A unicode character
-        err    error     // Error in case if input failed
-    }
+	keyEvent struct {
+		key  Key   // One of Key* constants, invalid if 'Ch' is not 0
+		rune rune  // A unicode character
+		err  error // Error in case if input failed
+	}
 )
 
 // Key constants, see GetKey() function.
 const (
-    KeyF1 Key = 0xFFFF - iota
-    KeyF2
-    KeyF3
-    KeyF4
-    KeyF5
-    KeyF6
-    KeyF7
-    KeyF8
-    KeyF9
-    KeyF10
-    KeyF11
-    KeyF12
-    KeyInsert
-    KeyDelete
-    KeyHome
-    KeyEnd
-    KeyPgup
-    KeyPgdn
-    KeyArrowUp
-    KeyArrowDown
-    KeyArrowLeft
-    KeyArrowRight
-    key_min // see terminfo
+	KeyF1 Key = 0xFFFF - iota
+	KeyF2
+	KeyF3
+	KeyF4
+	KeyF5
+	KeyF6
+	KeyF7
+	KeyF8
+	KeyF9
+	KeyF10
+	KeyF11
+	KeyF12
+	KeyInsert
+	KeyDelete
+	KeyHome
+	KeyEnd
+	KeyPgup
+	KeyPgdn
+	KeyArrowUp
+	KeyArrowDown
+	KeyArrowLeft
+	KeyArrowRight
+	key_min // see terminfo
 )
 
 const (
-    KeyCtrlTilde      Key = 0x00
-    KeyCtrl2          Key = 0x00
-    KeyCtrlSpace      Key = 0x00
-    KeyCtrlA          Key = 0x01
-    KeyCtrlB          Key = 0x02
-    KeyCtrlC          Key = 0x03
-    KeyCtrlD          Key = 0x04
-    KeyCtrlE          Key = 0x05
-    KeyCtrlF          Key = 0x06
-    KeyCtrlG          Key = 0x07
-    KeyBackspace      Key = 0x08
-    KeyCtrlH          Key = 0x08
-    KeyTab            Key = 0x09
-    KeyCtrlI          Key = 0x09
-    KeyCtrlJ          Key = 0x0A
-    KeyCtrlK          Key = 0x0B
-    KeyCtrlL          Key = 0x0C
-    KeyEnter          Key = 0x0D
-    KeyCtrlM          Key = 0x0D
-    KeyCtrlN          Key = 0x0E
-    KeyCtrlO          Key = 0x0F
-    KeyCtrlP          Key = 0x10
-    KeyCtrlQ          Key = 0x11
-    KeyCtrlR          Key = 0x12
-    KeyCtrlS          Key = 0x13
-    KeyCtrlT          Key = 0x14
-    KeyCtrlU          Key = 0x15
-    KeyCtrlV          Key = 0x16
-    KeyCtrlW          Key = 0x17
-    KeyCtrlX          Key = 0x18
-    KeyCtrlY          Key = 0x19
-    KeyCtrlZ          Key = 0x1A
-    KeyEsc            Key = 0x1B
-    KeyCtrlLsqBracket Key = 0x1B
-    KeyCtrl3          Key = 0x1B
-    KeyCtrl4          Key = 0x1C
-    KeyCtrlBackslash  Key = 0x1C
-    KeyCtrl5          Key = 0x1D
-    KeyCtrlRsqBracket Key = 0x1D
-    KeyCtrl6          Key = 0x1E
-    KeyCtrl7          Key = 0x1F
-    KeyCtrlSlash      Key = 0x1F
-    KeyCtrlUnderscore Key = 0x1F
-    KeySpace          Key = 0x20
-    KeyBackspace2     Key = 0x7F
-    KeyCtrl8          Key = 0x7F
+	KeyCtrlTilde      Key = 0x00
+	KeyCtrl2          Key = 0x00
+	KeyCtrlSpace      Key = 0x00
+	KeyCtrlA          Key = 0x01
+	KeyCtrlB          Key = 0x02
+	KeyCtrlC          Key = 0x03
+	KeyCtrlD          Key = 0x04
+	KeyCtrlE          Key = 0x05
+	KeyCtrlF          Key = 0x06
+	KeyCtrlG          Key = 0x07
+	KeyBackspace      Key = 0x08
+	KeyCtrlH          Key = 0x08
+	KeyTab            Key = 0x09
+	KeyCtrlI          Key = 0x09
+	KeyCtrlJ          Key = 0x0A
+	KeyCtrlK          Key = 0x0B
+	KeyCtrlL          Key = 0x0C
+	KeyEnter          Key = 0x0D
+	KeyCtrlM          Key = 0x0D
+	KeyCtrlN          Key = 0x0E
+	KeyCtrlO          Key = 0x0F
+	KeyCtrlP          Key = 0x10
+	KeyCtrlQ          Key = 0x11
+	KeyCtrlR          Key = 0x12
+	KeyCtrlS          Key = 0x13
+	KeyCtrlT          Key = 0x14
+	KeyCtrlU          Key = 0x15
+	KeyCtrlV          Key = 0x16
+	KeyCtrlW          Key = 0x17
+	KeyCtrlX          Key = 0x18
+	KeyCtrlY          Key = 0x19
+	KeyCtrlZ          Key = 0x1A
+	KeyEsc            Key = 0x1B
+	KeyCtrlLsqBracket Key = 0x1B
+	KeyCtrl3          Key = 0x1B
+	KeyCtrl4          Key = 0x1C
+	KeyCtrlBackslash  Key = 0x1C
+	KeyCtrl5          Key = 0x1D
+	KeyCtrlRsqBracket Key = 0x1D
+	KeyCtrl6          Key = 0x1E
+	KeyCtrl7          Key = 0x1F
+	KeyCtrlSlash      Key = 0x1F
+	KeyCtrlUnderscore Key = 0x1F
+	KeySpace          Key = 0x20
+	KeyBackspace2     Key = 0x7F
+	KeyCtrl8          Key = 0x7F
 )
 
 var (
-    isOpen        bool = false
-    waitingForKey bool = false
+	isOpen        bool = false
+	waitingForKey bool = false
 
-    input_comm = make(chan keyEvent)
-    cancel_key = make(chan struct{})
+	input_comm = make(chan keyEvent)
+	cancel_key = make(chan struct{})
 )
 
 func Open() (err error) {
-    if (isOpen) {
-        return
-    }
-    err = initConsole()
-    if err == nil {
-        isOpen = true
-    }
-    return
+	if isOpen {
+		return
+	}
+	err = initConsole()
+	if err == nil {
+		isOpen = true
+	}
+	return
 }
 
 // Should be called after successful initialization when functionality isn't required anymore.
 func Close() {
-    if !isOpen {
-        return
-    }
-    if waitingForKey {
-        cancel_key <- struct{}{}
-    }
-    releaseConsole()
-    isOpen = false
+	if !isOpen {
+		return
+	}
+	if waitingForKey {
+		cancel_key <- struct{}{}
+	}
+	releaseConsole()
+	isOpen = false
 }
 
 func GetKey() (rune, Key, error) {
-    if !isOpen {
-        panic("function GetKey() should be called after Open()")
-    }
-    waitingForKey = true
-    defer func() { waitingForKey = false }()
-
-    select {
-    case ev := <-input_comm:
-        return ev.rune, ev.key, ev.err
-
-    case <-cancel_key:
-        return 0, 0, nil
-    }
+	if !isOpen {
+		panic("function GetKey() should be called after Open()")
+	}
+	waitingForKey = true
+	defer func() { waitingForKey = false }()
+
+	select {
+	case ev := <-input_comm:
+		return ev.rune, ev.key, ev.err
+
+	case <-cancel_key:
+		return 0, 0, nil
+	}
+}
+
+func GetKeyNonBlocking() (rune, Key, error) {
+	if !isOpen {
+		panic("function GetKeyNonBlocking() should be called after Open()")
+	}
+	waitingForKey = true
+	defer func() { waitingForKey = false }()
+
+	select {
+	case ev := <-input_comm:
+		return ev.rune, ev.key, ev.err
+
+	case <-cancel_key:
+		return 0, 0, nil
+	default:
+		return 0, 0, nil
+	}
 }
 
 func GetSingleKey() (ch rune, key Key, err error) {
-    err = Open()
-    if err == nil {
-        ch, key, err = GetKey()
-        Close()
-    }
-    return
-}
+	err = Open()
+	if err == nil {
+		ch, key, err = GetKey()
+		Close()
+	}
+	return
+}
+
+func GetSingleKeyNonBlocking() (ch rune, key Key, err error) {
+	err = Open()
+	if err == nil {
+		ch, key, err = GetKeyNonBlocking()
+	}
+	return
+}