Improve documentation.

README.md

@@ -2,7 +2,9 @@
 
 [![GoDoc](https://godoc.org/github.com/ncruces/zenity?status.svg)](https://godoc.org/github.com/ncruces/zenity)
 
-This repo includes both a cross-platform Go package providing [Zenity](https://help.gnome.org/users/zenity/)-like dialogs,
+This repo includes both a cross-platform Go package providing
+[Zenity](https://help.gnome.org/users/zenity/)-like dialogs
+(simple dialogs that interact graphically with the user),
 as well as a *“port”* of the `zenity` command to both Windows and macOS based on that library.
 
 **This is a work in progress.**

color.go

@@ -0,0 +1,22 @@
+package zenity
+
+import "image/color"
+
+// SelectColor displays the color selection dialog.
+//
+// Returns nil on cancel.
+//
+// Valid options: Title, Color, ShowPalette.
+func SelectColor(options ...Option) (color.Color, error) {
+	return selectColor(options...)
+}
+
+// Color returns an Option to set the color.
+func Color(c color.Color) Option {
+	return func(o *options) { o.color = c }
+}
+
+// ShowPalette returns an Option to show the palette.
+func ShowPalette() Option {
+	return func(o *options) { o.palette = true }
+}

color_darwin.go

@@ -7,7 +7,7 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-func SelectColor(options ...Option) (color.Color, error) {
+func selectColor(options ...Option) (color.Color, error) {
 	opts := optsParse(options)
 
 	var data zenutil.Color

color_unix.go

@@ -9,12 +9,7 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-// Display color selection dialog.
-//
-// Returns nil on cancel.
-//
-// Valid options: Title, Color, ShowPalette.
-func SelectColor(options ...Option) (color.Color, error) {
+func selectColor(options ...Option) (color.Color, error) {
 	opts := optsParse(options)
 
 	args := []string{"--color-selection"}

color_windows.go

@@ -20,7 +20,7 @@ func init() {
 	}
 }
 
-func SelectColor(options ...Option) (color.Color, error) {
+func selectColor(options ...Option) (color.Color, error) {
 	opts := optsParse(options)
 
 	// load custom colors

file.go

@@ -5,6 +5,87 @@ import (
 	"path/filepath"
 )
 
+// SelectFile displays the file selection dialog.
+//
+// Returns an empty string on cancel.
+//
+// Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
+func SelectFile(options ...Option) (string, error) {
+	return selectFile(options...)
+}
+
+// SelectFileMutiple displays the multiple file selection dialog.
+//
+// Returns a nil slice on cancel.
+//
+// Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
+func SelectFileMutiple(options ...Option) ([]string, error) {
+	return selectFileMutiple(options...)
+}
+
+// SelectFileSave displays the save file selection dialog.
+//
+// Returns an empty string on cancel.
+//
+// Valid options: Title, Filename, ConfirmOverwrite, ConfirmCreate, ShowHidden,
+// FileFilter(s).
+func SelectFileSave(options ...Option) (string, error) {
+	return selectFileSave(options...)
+}
+
+// Filename returns an Option to set the filename.
+//
+// You can specify a file name, a directory path, or both.
+// Specifying a file name, makes it the default selected file.
+// Specifying a directory path, makes it the default dialog location.
+func Filename(filename string) Option {
+	return func(o *options) { o.filename = filename }
+}
+
+// Directory returns an Option to activate directory-only selection.
+func Directory() Option {
+	return func(o *options) { o.directory = true }
+}
+
+// ConfirmOverwrite returns an Option to confirm file selection if filename
+// already exists.
+func ConfirmOverwrite() Option {
+	return func(o *options) { o.overwrite = true }
+}
+
+// ConfirmCreate returns an Option to confirm file selection if filename does
+// not yet exist (Windows only).
+func ConfirmCreate() Option {
+	return func(o *options) { o.create = true }
+}
+
+// ShowHidden returns an Option to show hidden files (Windows and macOS only).
+func ShowHidden() Option {
+	return func(o *options) { o.hidden = true }
+}
+
+// FileFilter encapsulates a filename filter.
+//
+// macOS hides filename filters from the user,
+// and only supports filtering by extension (or "type").
+type FileFilter struct {
+	Name     string   // display string that describes the filter (optional)
+	Patterns []string // filter patterns for the display string
+}
+
+// Build returns an Option to set a filename filter.
+func (f FileFilter) Build() Option {
+	return func(o *options) { o.filters = append(o.filters, f) }
+}
+
+// FileFilters is a list of filename filters.
+type FileFilters []FileFilter
+
+// Build returns an Option to set filename filters.
+func (f FileFilters) Build() Option {
+	return func(o *options) { o.filters = append(o.filters, f...) }
+}
+
 func splitDirAndName(path string) (dir, name string) {
 	path = filepath.Clean(path)
 	fi, err := os.Stat(path)

file_darwin.go

@@ -7,7 +7,7 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-func SelectFile(options ...Option) (string, error) {
+func selectFile(options ...Option) (string, error) {
 	opts := optsParse(options)
 
 	data := zenutil.File{
@@ -35,7 +35,7 @@ func SelectFile(options ...Option) (string, error) {
 	return string(out), nil
 }
 
-func SelectFileMutiple(options ...Option) ([]string, error) {
+func selectFileMutiple(options ...Option) ([]string, error) {
 	opts := optsParse(options)
 
 	data := zenutil.File{
@@ -68,7 +68,7 @@ func SelectFileMutiple(options ...Option) ([]string, error) {
 	return strings.Split(string(out), zenutil.Separator), nil
 }
 
-func SelectFileSave(options ...Option) (string, error) {
+func selectFileSave(options ...Option) (string, error) {
 	opts := optsParse(options)
 
 	data := zenutil.File{

file_unix.go

@@ -9,12 +9,7 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-// Display file selection dialog.
-//
-// Returns an empty string on cancel.
-//
-// Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
-func SelectFile(options ...Option) (string, error) {
+func selectFile(options ...Option) (string, error) {
 	opts := optsParse(options)
 
 	args := []string{"--file-selection"}
@@ -42,12 +37,7 @@ func SelectFile(options ...Option) (string, error) {
 	return string(out), nil
 }
 
-// Display multiple file selection dialog.
-//
-// Returns a nil slice on cancel.
-//
-// Valid options: Title, Directory, Filename, ShowHidden, FileFilter(s).
-func SelectFileMutiple(options ...Option) ([]string, error) {
+func selectFileMutiple(options ...Option) ([]string, error) {
 	opts := optsParse(options)
 
 	args := []string{"--file-selection", "--multiple", "--separator", zenutil.Separator}
@@ -75,12 +65,7 @@ func SelectFileMutiple(options ...Option) ([]string, error) {
 	return strings.Split(string(out), zenutil.Separator), nil
 }
 
-// Display save file selection dialog.
-//
-// Returns an empty string on cancel.
-//
-// Valid options: Title, Filename, ConfirmOverwrite, ConfirmCreate, ShowHidden, FileFilter(s).
-func SelectFileSave(options ...Option) (string, error) {
+func selectFileSave(options ...Option) (string, error) {
 	opts := optsParse(options)
 
 	args := []string{"--file-selection", "--save"}

file_windows.go

@@ -17,7 +17,7 @@ var (
 	shCreateItemFromParsingName = shell32.NewProc("SHCreateItemFromParsingName")
 )
 
-func SelectFile(options ...Option) (string, error) {
+func selectFile(options ...Option) (string, error) {
 	opts := optsParse(options)
 	if opts.directory {
 		res, _, err := pickFolders(opts, false)
@@ -53,7 +53,7 @@ func SelectFile(options ...Option) (string, error) {
 	return syscall.UTF16ToString(res[:]), nil
 }
 
-func SelectFileMutiple(options ...Option) ([]string, error) {
+func selectFileMutiple(options ...Option) ([]string, error) {
 	opts := optsParse(options)
 	if opts.directory {
 		_, res, err := pickFolders(opts, true)
@@ -114,7 +114,7 @@ func SelectFileMutiple(options ...Option) ([]string, error) {
 	return split, nil
 }
 
-func SelectFileSave(options ...Option) (string, error) {
+func selectFileSave(options ...Option) (string, error) {
 	opts := optsParse(options)
 	if opts.directory {
 		res, _, err := pickFolders(opts, false)

internal/zenutil/env_unix.go

@@ -1,5 +1,6 @@
 // +build !windows,!darwin
 
+// Package zenutil is internal. DO NOT USE.
 package zenutil
 
 const LineBreak = "\n"

msg.go

@@ -0,0 +1,97 @@
+package zenity
+
+// ErrExtraButton is returned by dialog functions when the extra button is
+// pressed.
+const ErrExtraButton = constError("Extra button pressed.")
+
+// Question displays the question dialog.
+//
+// Returns true on OK, false on Cancel, or ErrExtraButton.
+//
+// Valid options: Title, Icon, OKLabel, CancelLabel, ExtraButton, NoWrap,
+// Ellipsize, DefaultCancel.
+func Question(text string, options ...Option) (bool, error) {
+	return message(questionKind, text, options)
+}
+
+// Info displays the info dialog.
+//
+// Returns true on OK, false on dismiss, or ErrExtraButton.
+//
+// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
+func Info(text string, options ...Option) (bool, error) {
+	return message(infoKind, text, options)
+}
+
+// Warning displays the warning dialog.
+//
+// Returns true on OK, false on dismiss, or ErrExtraButton.
+//
+// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
+func Warning(text string, options ...Option) (bool, error) {
+	return message(warningKind, text, options)
+}
+
+// Error displays the error dialog.
+//
+// Returns true on OK, false on dismiss, or ErrExtraButton.
+//
+// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
+func Error(text string, options ...Option) (bool, error) {
+	return message(errorKind, text, options)
+}
+
+type messageKind int
+
+const (
+	questionKind messageKind = iota
+	infoKind
+	warningKind
+	errorKind
+)
+
+// MessageIcon is the enumeration for message dialog icons.
+type MessageIcon int
+
+// Icons for
+const (
+	ErrorIcon MessageIcon = iota + 1
+	WarningIcon
+	InfoIcon
+	QuestionIcon
+)
+
+// Icon returns an Option to set the dialog icon.
+func Icon(icon MessageIcon) Option {
+	return func(o *options) { o.icon = icon }
+}
+
+// OKLabel returns an Option to set the label of the OK button.
+func OKLabel(ok string) Option {
+	return func(o *options) { o.ok = ok }
+}
+
+// CancelLabel returns an Option to set the label of the Cancel button.
+func CancelLabel(cancel string) Option {
+	return func(o *options) { o.cancel = cancel }
+}
+
+// ExtraButton returns an Option to add an extra button.
+func ExtraButton(extra string) Option {
+	return func(o *options) { o.extra = extra }
+}
+
+// NoWrap returns an Option to disable enable text wrapping.
+func NoWrap() Option {
+	return func(o *options) { o.nowrap = true }
+}
+
+// Ellipsize returns an Option to enable ellipsizing in the dialog text.
+func Ellipsize() Option {
+	return func(o *options) { o.ellipsize = true }
+}
+
+// DefaultCancel returns an Option to give Cancel button focus by default.
+func DefaultCancel() Option {
+	return func(o *options) { o.defcancel = true }
+}

msg_darwin.go

@@ -6,26 +6,10 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-func Question(text string, options ...Option) (bool, error) {
-	return message(0, text, options)
-}
-
-func Info(text string, options ...Option) (bool, error) {
-	return message(1, text, options)
-}
-
-func Warning(text string, options ...Option) (bool, error) {
-	return message(2, text, options)
-}
-
-func Error(text string, options ...Option) (bool, error) {
-	return message(3, text, options)
-}
-
-func message(typ int, text string, options []Option) (bool, error) {
+func message(kind messageKind, text string, options []Option) (bool, error) {
 	opts := optsParse(options)
 	data := zenutil.Msg{Text: text}
-	dialog := typ == 0 || opts.icon != 0
+	dialog := kind == questionKind || opts.icon != 0
 
 	if dialog {
 		data.Operation = "displayDialog"
@@ -46,17 +30,17 @@ func message(typ int, text string, options []Option) (bool, error) {
 			data.Text = opts.title
 		}
 
-		switch typ {
-		case 1:
+		switch kind {
+		case infoKind:
 			data.As = "informational"
-		case 2:
+		case warningKind:
 			data.As = "warning"
-		case 3:
+		case errorKind:
 			data.As = "critical"
 		}
 	}
 
-	if typ != 0 {
+	if kind != questionKind {
 		if dialog {
 			opts.ok = "OK"
 		}
@@ -69,7 +53,7 @@ func message(typ int, text string, options []Option) (bool, error) {
 		if opts.cancel == "" {
 			opts.cancel = "Cancel"
 		}
-		if typ == 0 {
+		if kind == questionKind {
 			if opts.extra == "" {
 				data.Buttons = []string{opts.cancel, opts.ok}
 				data.Default = 2

msg_unix.go

@@ -8,47 +8,20 @@ import (
 	"github.com/ncruces/zenity/internal/zenutil"
 )
 
-// Display question dialog.
-//
-// Returns true on OK, false on Cancel, or ErrExtraButton.
-//
-// Valid options: Title, Icon, OKLabel, CancelLabel, ExtraButton, NoWrap,
-// Ellipsize, DefaultCancel.
-func Question(text string, options ...Option) (bool, error) {
-	return message("--question", text, options)
-}
-
-// Display info dialog.
-//
-// Returns true on OK, false on dismiss, or ErrExtraButton.
-//
-// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
-func Info(text string, options ...Option) (bool, error) {
-	return message("--info", text, options)
-}
-
-// Display warning dialog.
-//
-// Returns true on OK, false on dismiss, or ErrExtraButton.
-//
-// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
-func Warning(text string, options ...Option) (bool, error) {
-	return message("--warning", text, options)
-}
-
-// Display error dialog.
-//
-// Returns true on OK, false on dismiss, or ErrExtraButton.
-//
-// Valid options: Title, Icon, OKLabel, ExtraButton, NoWrap, Ellipsize.
-func Error(text string, options ...Option) (bool, error) {
-	return message("--error", text, options)
-}
-
-func message(arg, text string, options []Option) (bool, error) {
+func message(kind messageKind, text string, options []Option) (bool, error) {
 	opts := optsParse(options)
 
-	args := []string{arg}
+	var args []string
+	switch kind {
+	case questionKind:
+		args = append(args, "--question")
+	case infoKind:
+		args = append(args, "--info")
+	case warningKind:
+		args = append(args, "--warning")
+	case errorKind:
+		args = append(args, "--error")
+	}
 	if text != "" {
 		args = append(args, "--text", text, "--no-markup")
 	}

msg_windows.go

@@ -10,31 +10,15 @@ var (
 	messageBox = user32.NewProc("MessageBoxW")
 )
 
-func Question(text string, options ...Option) (bool, error) {
-	return message(0, text, options)
-}
-
-func Info(text string, options ...Option) (bool, error) {
-	return message(1, text, options)
-}
-
-func Warning(text string, options ...Option) (bool, error) {
-	return message(2, text, options)
-}
-
-func Error(text string, options ...Option) (bool, error) {
-	return message(3, text, options)
-}
-
-func message(typ int, text string, options []Option) (bool, error) {
+func message(kind messageKind, text string, options []Option) (bool, error) {
 	opts := optsParse(options)
 
 	var flags, caption uintptr
 
 	switch {
-	case typ == 0 && opts.extra != "":
+	case kind == questionKind && opts.extra != "":
 		flags |= 0x3 // MB_YESNOCANCEL
-	case typ == 0 || opts.extra != "":
+	case kind == questionKind || opts.extra != "":
 		flags |= 0x1 // MB_OKCANCEL
 	}
 
@@ -49,7 +33,7 @@ func message(typ int, text string, options []Option) (bool, error) {
 		flags |= 0x40 // MB_ICONINFORMATION
 	}
 
-	if typ == 0 && opts.defcancel {
+	if kind == questionKind && opts.defcancel {
 		if opts.extra == "" {
 			flags |= 0x100 // MB_DEFBUTTON2
 		} else {
@@ -65,7 +49,7 @@ func message(typ int, text string, options []Option) (bool, error) {
 		runtime.LockOSThread()
 		defer runtime.UnlockOSThread()
 
-		hook, err := hookMessageLabels(typ, opts)
+		hook, err := hookMessageLabels(kind, opts)
 		if hook == 0 {
 			return false, err
 		}
@@ -79,7 +63,7 @@ func message(typ int, text string, options []Option) (bool, error) {
 	if n == 0 {
 		return false, err
 	}
-	if n == 7 || n == 2 && typ != 0 { // IDNO
+	if n == 7 || n == 2 && kind != questionKind { // IDNO
 		return false, ErrExtraButton
 	}
 	if n == 1 || n == 6 { // IDOK, IDYES
@@ -88,7 +72,7 @@ func message(typ int, text string, options []Option) (bool, error) {
 	return false, nil
 }
 
-func hookMessageLabels(typ int, opts options) (hook uintptr, err error) {
+func hookMessageLabels(kind messageKind, opts options) (hook uintptr, err error) {
 	tid, _, _ := getCurrentThreadId.Call()
 	hook, _, err = setWindowsHookEx.Call(12, // WH_CALLWNDPROCRET
 		syscall.NewCallback(func(code int, wparam uintptr, lparam *_CWPRETSTRUCT) uintptr {
@@ -107,7 +91,7 @@ func hookMessageLabels(typ int, opts options) (hook uintptr, err error) {
 								case 1, 6: // IDOK, IDYES
 									text = opts.ok
 								case 2: // IDCANCEL
-									if typ == 0 {
+									if kind == questionKind {
 										text = opts.cancel
 									} else if opts.extra != "" {
 										text = opts.extra

zenity.go

@@ -1,19 +1,21 @@
+// Package zenity provides cross-platform access to simple dialogs that interact
+// graphically with the user.
+//
+// It is inspired by, and closely follows the API of, the zenity program, which
+// it uses to provide the functionality on various Unixes. See:
+//
+// https://help.gnome.org/users/zenity/
+//
+// This package does not require cgo, and it does not impose any threading or
+// initialization requirements.
 package zenity
 
 import "image/color"
 
-// Errors
-
 type constError string
 
 func (e constError) Error() string { return string(e) }
 
-// Message errors
-
-const ErrExtraButton = constError("Extra button pressed.")
-
-// Options
-
 type options struct {
 	// General options
 	title string
@@ -40,7 +42,8 @@ type options struct {
 	defcancel bool
 }
 
-// Options are arguments passed to dialog functions to customize their behavior.
+// An Option is an argument passed to dialog functions to customize their
+// behavior.
 type Option func(*options)
 
 func optsParse(options []Option) (res options) {
@@ -50,121 +53,7 @@ func optsParse(options []Option) (res options) {
 	return
 }
 
-// General options
-
-// Option to set the dialog title.
+// Title returns an Option to set the dialog title.
 func Title(title string) Option {
 	return func(o *options) { o.title = title }
 }
-
-// File selection options
-
-// Option to set the filename.
-//
-// You can specify a file name, a directory path, or both.
-// Specifying a file name, makes it the default selected file.
-// Specifying a directory path, makes it the default dialog location.
-func Filename(filename string) Option {
-	return func(o *options) { o.filename = filename }
-}
-
-// Option to activate directory-only selection.
-func Directory() Option {
-	return func(o *options) { o.directory = true }
-}
-
-// Option to confirm file selection if filename already exists.
-func ConfirmOverwrite() Option {
-	return func(o *options) { o.overwrite = true }
-}
-
-// Option to confirm file selection if filename does not yet exist (Windows only).
-func ConfirmCreate() Option {
-	return func(o *options) { o.create = true }
-}
-
-// Option to show hidden files (Windows and macOS only).
-func ShowHidden() Option {
-	return func(o *options) { o.hidden = true }
-}
-
-// FileFilter encapsulates a filename filter.
-//
-// macOS hides filename filters from the user,
-// and only supports filtering by extension (or "type").
-type FileFilter struct {
-	Name     string   // display string that describes the filter (optional)
-	Patterns []string // filter patterns for the display string
-}
-
-// Build option to set a filename filter.
-func (f FileFilter) Build() Option {
-	return func(o *options) { o.filters = append(o.filters, f) }
-}
-
-// FileFilters is a list of filename filters.
-type FileFilters []FileFilter
-
-// Build option to set filename filters.
-func (f FileFilters) Build() Option {
-	return func(o *options) { o.filters = append(o.filters, f...) }
-}
-
-// Color selection options
-
-// Option to set the color.
-func Color(c color.Color) Option {
-	return func(o *options) { o.color = c }
-}
-
-// Option to show the palette.
-func ShowPalette() Option {
-	return func(o *options) { o.palette = true }
-}
-
-// Message options
-
-// MessageIcon is the enumeration for message dialog icons.
-type MessageIcon int
-
-const (
-	ErrorIcon MessageIcon = iota + 1
-	WarningIcon
-	InfoIcon
-	QuestionIcon
-)
-
-// Option to set the dialog icon.
-func Icon(icon MessageIcon) Option {
-	return func(o *options) { o.icon = icon }
-}
-
-// Option to set the label of the OK button.
-func OKLabel(ok string) Option {
-	return func(o *options) { o.ok = ok }
-}
-
-// Option to set the label of the Cancel button.
-func CancelLabel(cancel string) Option {
-	return func(o *options) { o.cancel = cancel }
-}
-
-// Option to add an extra button.
-func ExtraButton(extra string) Option {
-	return func(o *options) { o.extra = extra }
-}
-
-// Option to disable enable text wrapping.
-func NoWrap() Option {
-	return func(o *options) { o.nowrap = true }
-}
-
-// Option to enable ellipsizing in the dialog text.
-func Ellipsize() Option {
-	return func(o *options) { o.ellipsize = true }
-}
-
-// Option to give Cancel button focus by default.
-func DefaultCancel() Option {
-	return func(o *options) { o.defcancel = true }
-}