Trigger ExitChecker on pressed keys (#162)

* prompt.go handleKeyBinding can indicate one should Exit if an exit checker function is set

* Use new name exitChecker instead of old exitor

* ExitChecker API change: breakline bool

- breakline true means the executor has been called: check for exit
- breakline false means no executor, just a character typed: check for
exit

prompt.go

@@ -12,9 +12,11 @@ import (
 type Executor func(string)
 
 // ExitChecker is called after user input to check if prompt must stop and exit go-prompt Run loop.
-// User input means: selecting/typing an entry, then <return>, and the executor is called.
-// Then, if said entry content matches the ExitChecker function criteria, exit go-prompt (not the overall Go program)
-type ExitChecker func(string) bool
+// User input means: selecting/typing an entry, then, if said entry content matches the ExitChecker function criteria:
+// - immediate exit (if breakline is false) without executor called
+// - exit after typing <return> (meaning breakline is true), and the executor is called first, before exit.
+// Exit means exit go-prompt (not the overall Go program)
+type ExitChecker func(in string, breakline bool) bool
 
 // Completer should return the suggest item from Document.
 type Completer func(Document) []Suggest
@@ -85,7 +87,7 @@ func (p *Prompt) Run() {
 
 				p.renderer.Render(p.buf, p.completion)
 
-				if p.exitChecker != nil && p.exitChecker(e.input) {
+				if p.exitChecker != nil && p.exitChecker(e.input, true) {
 					p.skipTearDown = true
 					return
 				}
@@ -155,7 +157,7 @@ func (p *Prompt) feed(b []byte) (shouldExit bool, exec *Exec) {
 		p.buf.InsertText(string(b), false, true)
 	}
 
-	p.handleKeyBinding(key)
+	shouldExit = p.handleKeyBinding(key)
 	return
 }
 
@@ -185,7 +187,8 @@ func (p *Prompt) handleCompletionKeyBinding(key Key, completing bool) {
 	}
 }
 
-func (p *Prompt) handleKeyBinding(key Key) {
+func (p *Prompt) handleKeyBinding(key Key) bool {
+	shouldExit := false
 	for i := range commonKeyBindings {
 		kb := commonKeyBindings[i]
 		if kb.Key == key {
@@ -209,6 +212,10 @@ func (p *Prompt) handleKeyBinding(key Key) {
 			kb.Fn(p.buf)
 		}
 	}
+	if p.exitChecker != nil && p.exitChecker(p.buf.Text(), false) {
+		shouldExit = true
+	}
+	return shouldExit
 }
 
 func (p *Prompt) handleASCIICodeBinding(b []byte) bool {