From 7f161e668319deb75f6a3959dea790d8fad2ce9e Mon Sep 17 00:00:00 2001
From: Renzix <31043283+Renzix@users.noreply.github.com>
Date: Thu, 14 Apr 2022 07:42:46 -0400
Subject: [PATCH] feat: added forward/backward word keybinds (#139)

Added emacsForwardWord and emacsBackwardWord which is used by M-f and
M-b directly. Also added M-d to ctrl delete and removed the bad old
funcion in favor of the fancy new one. Lastly I added alt delete which
deletes with emacsBackwardWord. Works identically to gnu readline

Co-authored-by: Renzix <DanielDeBruno@renzix.com>
---
 readline/codes.go    |  4 ++++
 readline/line.go     | 31 +++++++++++++++++++++++--------
 readline/readline.go | 42 +++++++++++++++++++++++++++++++++++++-----
 3 files changed, 64 insertions(+), 13 deletions(-)

diff --git a/readline/codes.go b/readline/codes.go
index e97af90..29d7462 100644
--- a/readline/codes.go
+++ b/readline/codes.go
@@ -50,8 +50,12 @@ var (
 	seqDelete2      = string([]byte{27, 91, 80})
 	seqCtrlDelete   = string([]byte{27, 91, 51, 59, 53, 126})
 	seqCtrlDelete2  = string([]byte{27, 91, 77})
+	seqAltDelete    = string([]byte{27, 91, 51, 59, 51, 126})
 	seqShiftTab     = string([]byte{27, 91, 90})
 	seqAltQuote     = string([]byte{27, 34})  // Added for showing registers ^["
+	seqAltB         = string([]byte{27, 98})
+	seqAltD         = string([]byte{27, 100})
+	seqAltF         = string([]byte{27, 102})
 	seqAltR         = string([]byte{27, 114}) // Used for alternative history
 	seqAltBackspace = string([]byte{27, 127})
 )
diff --git a/readline/line.go b/readline/line.go
index 274d11b..be5ef2c 100644
--- a/readline/line.go
+++ b/readline/line.go
@@ -183,26 +183,41 @@ func (rl *Instance) deleteToEnd() {
 	rl.line = rl.line[:rl.pos]
 }
 
+// @TODO(Renzix): move to emacs sepecific file
 func (rl *Instance) emacsForwardWord(tokeniser tokeniser) (adjust int) {
-	// when emacs has more specific stuff, move this in a file with then
 	split, index, pos := tokeniser(rl.line, rl.pos)
 	if len(split) == 0 {
 		return
 	}
 
-	word := rTrimWhiteSpace(split[index])
+	word := strings.TrimSpace(split[index])
 
 	switch {
 	case len(split) == 0:
 		return
-	case index == len(split)-1 && pos >= len(word)-1:
-		return
-	case pos >= len(word)-1:
-		word = rTrimWhiteSpace(split[index+1])
-		adjust = len(split[index]) - pos
-		adjust += len(word)
+	case pos == len(word) && index != len(split)-1:
+		extrawhitespace := len(strings.TrimLeft(split[index], " ")) - len(word)
+		word = split[index+1]
+		adjust = len(word) + extrawhitespace
 	default:
 		adjust = len(word) - pos
 	}
 	return
 }
+
+func (rl *Instance) emacsBackwardWord(tokeniser tokeniser) (adjust int) {
+	split, index, pos := tokeniser(rl.line, rl.pos)
+	if len(split) == 0 {
+		return
+	}
+
+	switch {
+	case len(split) == 0:
+		return
+	case pos == 0 && index != 0:
+		adjust = len(split[index-1])
+	default:
+		adjust = pos
+	}
+	return
+}
diff --git a/readline/readline.go b/readline/readline.go
index 255fcd6..925bc8f 100644
--- a/readline/readline.go
+++ b/readline/readline.go
@@ -761,6 +761,34 @@ func (rl *Instance) escapeSeq(r []rune) {
 		rl.pos = len(rl.line)
 		rl.viUndoSkipAppend = true
 
+	case seqAltB:
+		if rl.modeTabCompletion {
+			return
+		}
+
+		// This is only available in Insert mode
+		if rl.modeViMode != VimInsert {
+			return
+		}
+
+		move := rl.emacsBackwardWord(tokeniseLine)
+		rl.moveCursorByAdjust(-move)
+		rl.updateHelpers()
+
+	case seqAltF:
+		if rl.modeTabCompletion {
+			return
+		}
+
+		// This is only available in Insert mode
+		if rl.modeViMode != VimInsert {
+			return
+		}
+
+		move := rl.emacsForwardWord(tokeniseLine)
+		rl.moveCursorByAdjust(move)
+		rl.updateHelpers()
+
 	case seqAltR:
 		rl.resetVirtualComp(false)
 		// For some modes only, if we are in vim Keys mode,
@@ -792,19 +820,23 @@ func (rl *Instance) escapeSeq(r []rune) {
 		rl.viDeleteByAdjust(rl.viJumpB(tokeniseLine))
 		rl.updateHelpers()
 
-	case seqCtrlDelete, seqCtrlDelete2:
+	case seqCtrlDelete, seqCtrlDelete2, seqAltD:
 		if rl.modeTabCompletion {
 			rl.resetVirtualComp(false)
 		}
-		// This is only available in Insert mode
-		if rl.modeViMode != VimInsert {
-			return
-		}
 		rl.saveToRegister(rl.emacsForwardWord(tokeniseLine))
 		// vi delete, emacs forward, funny huh
 		rl.viDeleteByAdjust(rl.emacsForwardWord(tokeniseLine))
 		rl.updateHelpers()
 
+	case seqAltDelete:
+		if rl.modeTabCompletion {
+			rl.resetVirtualComp(false)
+		}
+		rl.saveToRegister(-rl.emacsBackwardWord(tokeniseLine))
+		rl.viDeleteByAdjust(-rl.emacsBackwardWord(tokeniseLine))
+		rl.updateHelpers()
+
 	default:
 		if rl.modeTabFind {
 			return