Add OptionShowCompletionAtStart option

completion.go

@@ -36,6 +36,7 @@ type CompletionManager struct {
 
 	verticalScroll int
 	wordSeparator  string
+	showAtStart    bool
 }
 
 // GetSelectedSuggestion returns the selected item.

option.go

@@ -225,6 +225,15 @@ func OptionAddASCIICodeBind(b ...ASCIICodeBind) Option {
 	}
 }
 
+// OptionShowCompletionAtStart to set whether completion window is open at start or not.
+// This option only affects Prompt.Input().
+func OptionShowCompletionAtStart() Option {
+	return func(p *Prompt) error {
+		p.completion.showAtStart = true
+		return nil
+	}
+}
+
 // New returns a Prompt with powerful auto-completion.
 func New(executor Executor, completer Completer, opts ...Option) *Prompt {
 	pt := &Prompt{

prompt.go

@@ -232,6 +232,9 @@ func (p *Prompt) Input() string {
 	p.setUp()
 	defer p.tearDown()
 
+	if p.completion.showAtStart {
+		p.completion.Update(*p.buf.Document())
+	}
 	p.renderer.Render(p.buf, p.completion)
 	bufCh := make(chan []byte, 128)
 	stopReadBufCh := make(chan struct{})