xP: implement Readline's M-b and M-f

xP/public/xP.js

@@ -692,7 +692,7 @@ let Input = {
 			textarea.selectionStart, textarea.selectionEnd, textarea.value]
 	},
 
-	complete: textarea => {
+	complete: (b, textarea) => {
 		if (textarea.selectionStart !== textarea.selectionEnd)
 			return false
 
@@ -726,7 +726,7 @@ let Input = {
 		return true
 	},
 
-	submit: textarea => {
+	submit: (b, textarea) => {
 		rpc.send({
 			command: 'BufferInput',
 			bufferName: bufferCurrent,
@@ -736,41 +736,76 @@ let Input = {
 		// b.history[b.history.length] is virtual, and is represented
 		// either by textarea contents when it's currently being edited,
 		// or by b.input in all other cases.
-		let b = buffers.get(bufferCurrent)
 		b.history.push(textarea.value)
 		b.historyAt = b.history.length
 		textarea.value = ''
 		return true
 	},
 
-	previous: textarea => {
-		let b = buffers.get(bufferCurrent)
-		if (b === undefined)
+	backward: (b, textarea) => {
+		if (textarea.selectionStart !== textarea.selectionEnd)
 			return false
 
-		if (b.historyAt > 0) {
-			if (b.historyAt == b.history.length)
-				b.input = textarea.value
-			textarea.value = b.history[--b.historyAt]
-		} else {
-			beep()
-		}
+		let point = textarea.selectionStart
+		if (point < 1)
+			return false
+		while (point && /\s/.test(textarea.value.charAt(--point))) {}
+		while (point-- && !/\s/.test(textarea.value.charAt(point))) {}
+		point++
+		textarea.setSelectionRange(point, point)
 		return true
 	},
 
-	next: textarea => {
-		let b = buffers.get(bufferCurrent)
-		if (b === undefined)
+	forward: (b, textarea) => {
+		if (textarea.selectionStart !== textarea.selectionEnd)
 			return false
 
-		if (b.historyAt < b.history.length) {
-			if (++b.historyAt == b.history.length)
-				textarea.value = b.input
-			else
-				textarea.value = b.history[b.historyAt]
-		} else {
-			beep()
-		}
+		let point = textarea.selectionStart, len = textarea.value.length
+		if (point + 1 > len)
+			return false
+		while (point < len && /\s/.test(textarea.value.charAt(point))) point++
+		while (point < len && !/\s/.test(textarea.value.charAt(point))) point++
+		textarea.setSelectionRange(point, point)
+		return true
+	},
+
+	first: (b, textarea) => {
+		if (b.historyAt <= 0)
+			return false
+
+		if (b.historyAt == b.history.length)
+			b.input = textarea.value
+		textarea.value = b.history[(b.historyAt = 0)]
+		return true
+	},
+
+	last: (b, textarea) => {
+		if (b.historyAt >= b.history.length)
+			return false
+
+		b.historyAt = b.history.length
+		textarea.value = b.input
+		return true
+	},
+
+	previous: (b, textarea) => {
+		if (b.historyAt <= 0)
+			return false
+
+		if (b.historyAt == b.history.length)
+			b.input = textarea.value
+		textarea.value = b.history[--b.historyAt]
+		return true
+	},
+
+	next: (b, textarea) => {
+		if (b.historyAt >= b.history.length)
+			return false
+
+		if (++b.historyAt == b.history.length)
+			textarea.value = b.input
+		else
+			textarea.value = b.history[b.historyAt]
 		return true
 	},
 
@@ -778,28 +813,35 @@ let Input = {
 		// TODO: And perhaps on other actions, too.
 		rpc.send({command: 'Active'})
 
+		let b = buffers.get(bufferCurrent)
+		if (b === undefined)
+			return
+
 		let textarea = event.currentTarget
 		let handled = false
+		let success = true
 		if (hasShortcutModifiers(event)) {
+			handled = true
 			switch (event.key) {
-			case 'p':
-				handled = Input.previous(textarea)
-				break
-			case 'n':
-				handled = Input.next(textarea)
-				break
+			case 'b': success = Input.backward(b, textarea); break
+			case 'f': success = Input.forward(b, textarea);  break
+			case '<': success = Input.first(b, textarea);    break
+			case '>': success = Input.last(b, textarea);     break
+			case 'p': success = Input.previous(b, textarea); break
+			case 'n': success = Input.next(b, textarea);     break
+			default:  handled = false
 			}
 		} else if (!event.altKey && !event.ctrlKey && !event.metaKey &&
 				!event.shiftKey) {
+			handled = true
 			switch (event.keyCode) {
-			case 9:
-				handled = Input.complete(textarea)
-				break
-			case 13:
-				handled = Input.submit(textarea)
-				break
+			case 9:   success = Input.complete(b, textarea); break
+			case 13:  success = Input.submit(b, textarea);   break
+			default:  handled = false
 			}
 		}
+		if (!success)
+			beep()
 		if (handled)
 			event.preventDefault()
 	},