Changed manual sysData construction to use a helper function instead.

button.go

@@ -19,11 +19,7 @@ type Button struct {
 // NewButton creates a new button with the specified text.
 func NewButton(text string) (b *Button) {
 	return &Button{
-		sysData:	&sysData{
+		sysData:	mksysdata(c_button),
-			cSysData:		cSysData{
-				ctype:	c_button,
-			},
-		},
 		initText:	text,
 		Clicked:	make(chan struct{}),
 	}

checkbox.go

@@ -20,11 +20,7 @@ type Checkbox struct {
 // NewCheckbox creates a new checkbox with the specified text.
 func NewCheckbox(text string) (c *Checkbox) {
 	return &Checkbox{
-		sysData:	&sysData{
+		sysData:	mksysdata(c_checkbox),
-			cSysData:		cSysData{
-				ctype:	c_checkbox,
-			},
-		},
 		initText:	text,
 	}
 }

sysdata.go

@@ -36,3 +36,11 @@ const (
 	c_checkbox
 	nctypes
 )
+
+func mksysdata(ctype int) *sysData {
+	return &sysData{
+		cSysData:		cSysData{
+			ctype:	ctype,
+		},
+	}
+}

window.go

@@ -25,11 +25,7 @@ type Window struct {
 // NewWindow creates a new window with the given title and size. The window is not constructed at the OS level until a call to Open().
 func NewWindow(title string, width int, height int) *Window {
 	return &Window{
-		sysData:		&sysData{
+		sysData:		mksysdata(c_window),
-			cSysData:		cSysData{
-				ctype:	c_window,
-			},
-		},
 		initTitle:		title,
 		initWidth:		width,
 		initHeight:	height,