Complete kilo chapter 5, fix backspace and delete behavior

internal/editor/draw.go

@@ -74,7 +74,7 @@ func (e *editor) drawRows(ab *gilo.Buffer) {
 			}
 
 			rowLen := e.document.GetRow(fileRow).RenderSize() - e.offset.X
-			outputRow := truncate(e.document.GetRow(fileRow).Render(e.offset), rowLen)
+			outputRow := gilo.Truncate(e.document.GetRow(fileRow).Render(e.offset), rowLen)
 			ab.Append(outputRow)
 		}
 
@@ -86,7 +86,7 @@ func (e *editor) drawPlaceholderRow(y int, ab *gilo.Buffer) {
 	if e.document.RowCount() == 0 && y == e.screen.Rows/3 {
 		welcome := fmt.Sprintf("Gilo editor -- version %s", gilo.Version)
 		if len(welcome) > e.screen.Cols {
-			welcome = truncate(welcome, e.screen.Cols)
+			welcome = gilo.Truncate(welcome, e.screen.Cols)
 		}
 
 		padding := (e.screen.Cols - len(welcome)) / 2
@@ -123,7 +123,7 @@ func (e *editor) drawStatusBar(ab *gilo.Buffer) {
 	leftStatus := fmt.Sprintf("%.20s - %d lines %s", fileName, e.document.RowCount(), modified)
 	length := len(leftStatus)
 	if length > cols {
-		leftStatus = truncate(leftStatus, cols)
+		leftStatus = gilo.Truncate(leftStatus, cols)
 
 		ab.Append(leftStatus)
 		ab.Append(terminal.ResetColor)
@@ -161,7 +161,7 @@ func (e *editor) drawMessageBar(ab *gilo.Buffer) {
 	ab.Append("\r\n")
 	ab.Append(terminal.ClearLine)
 
-	msg := truncate(e.status.message, e.screen.Cols)
+	msg := gilo.Truncate(e.status.message, e.screen.Cols)
 	if len(msg) > 0 && time.Since(e.status.created).Seconds() < 5.0 {
 		ab.Append(msg)
 	}

internal/editor/editor.go

@@ -60,7 +60,10 @@ func (e *editor) Open(filename string) {
 
 func (e *editor) Save() {
 	if e.document.Filename == "" {
-		e.document.Filename = e.Prompt("Save as: %s")
+		e.document.Filename = e.Prompt("Save as: %s (ESC to cancel)")
+		if e.document.Filename == "" {
+			e.SetStatusMessage("Save aborted")
+		}
 	}
 
 	size := e.document.Save()
@@ -107,6 +110,16 @@ func (e *editor) Prompt(prompt string) string {
 			}
 		} else if key.IsAscii(ch) && !key.IsCtrl(ch) {
 			buf.AppendRune(ch)
+		} else if ch == key.Backspace || ch == key.Ctrl('h') {
+			buf.Truncate(buf.Len() - 1)
+		} else if ch == key.Esc {
+			k := parseEscapeSequence()
+			if k == keyDelete {
+				buf.Truncate(buf.Len() - 1)
+			} else if k == string(rune(key.Esc)) {
+				e.SetStatusMessage("")
+				return ""
+			}
 		}
 	}
 }
@@ -133,8 +146,6 @@ func (e *editor) delChar() {
 		at := e.cursor
 		at.X -= 1
 		e.document.DelChar(at)
-
-		e.cursor.X -= 1
 	} else {
 		// Move cursor to the current end of the previous line
 		e.cursor.X = e.document.GetRow(e.cursor.Y - 1).Size()

internal/gilo/buffer.go

@@ -45,6 +45,16 @@ func (b *Buffer) ToString() string {
 	return b.buf.String()
 }
 
+func (b *Buffer) Truncate(length int) string {
+	current := b.buf.String()
+	truncated := Truncate(current, length)
+
+	b.buf.Reset()
+	b.Append(truncated)
+
+	return truncated
+}
+
 func (b *Buffer) Len() int {
 	return b.buf.Len()
 }

internal/gilo/fn.go

@@ -1,10 +1,10 @@
 // Helper functions
-package editor
+package gilo
 
 import "strings"
 
 // Truncate a string to a length
-func truncate(s string, length int) string {
+func Truncate(s string, length int) string {
 	if length < 1 {
 		return ""
 	}

internal/gilo/fn_test.go

@@ -1,4 +1,4 @@
-package editor
+package gilo
 
 import (
 	"testing"
@@ -6,7 +6,7 @@ import (
 
 func TestTruncateString(t *testing.T) {
 	firstString := "abcdefghijklmnopqrstuvwxyz"
-	truncated := truncate(firstString, 13)
+	truncated := Truncate(firstString, 13)
 
 	got := len(truncated)
 	want := 13
@@ -17,7 +17,7 @@ func TestTruncateString(t *testing.T) {
 }
 
 func TestTruncateStringNegative(t *testing.T) {
-	got := truncate("fdlkjf", -5)
+	got := Truncate("fdlkjf", -5)
 	want := ""
 
 	if got != want {
@@ -28,7 +28,7 @@ func TestTruncateStringNegative(t *testing.T) {
 func TestTruncateShorterString(t *testing.T) {
 	str := "abcdefg"
 
-	got := truncate(str, 13)
+	got := Truncate(str, 13)
 	want := str
 
 	if got != want {