More intelligent text editing with new textmanip system

textmanip/textmanip.go

@@ -0,0 +1,99 @@
+package textmanip
+
+import "unicode"
+
+func WordToLeft (text []rune, cursor int) (length int) {
+	if cursor < 1 { return }
+	if cursor > len(text) { cursor = len(text) }
+
+	index := cursor - 1
+	for index >= 0 && unicode.IsSpace(text[index]) {
+		length ++
+		index --
+	}
+	for index >= 0 && !unicode.IsSpace(text[index]) {
+		length ++
+		index --
+	}
+	return
+}
+
+func WordToRight (text []rune, cursor int) (length int) {
+	if cursor < 0 { return }
+	if cursor > len(text) { cursor = len(text) }
+
+	index := cursor
+	for index < len(text) && unicode.IsSpace(text[index]) {
+		length ++
+		index ++
+	}
+	for index < len(text) && !unicode.IsSpace(text[index]) {
+		length ++
+		index ++
+	}
+	return
+}
+
+func Backspace (text []rune, cursor int, word bool) (result []rune, moved int) {
+	if cursor < 1         { return text, cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToLeft(text, cursor)
+	}
+	result = append(result, text[:cursor - moved]...)
+	result = append(result, text[cursor:]...)
+	moved = cursor - moved
+	return
+}
+
+func Delete (text []rune, cursor int, word bool) (result []rune, moved int) {
+	if cursor < 0         { return text, cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToRight(text, cursor)
+	}
+	result = append(result, text[:cursor]...)
+	result = append(result, text[cursor + moved:]...)
+	moved = cursor
+	return
+}
+
+func Type (text []rune, cursor int, character rune) (result []rune, moved int) {
+	if cursor < 0         { cursor = 0 }
+	if cursor > len(text) { cursor = len(text) }
+	result = append(result, text[:cursor]...)
+	result = append(result, character)
+	if cursor < len(text) {
+		result = append(result, text[cursor:]...)
+	}
+	moved = cursor + 1
+	return
+}
+
+func MoveLeft (text []rune, cursor int, word bool) (moved int) {
+	if cursor < 1         { return cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToLeft(text, cursor)
+	}
+	moved = cursor - moved
+	return
+}
+
+func MoveRight (text []rune, cursor int, word bool) (moved int) {
+	if cursor < 0         { return cursor }
+	if cursor > len(text) { cursor = len(text) }
+
+	moved = 1
+	if word {
+		moved = WordToRight(text, cursor)
+	}
+	moved = cursor + moved
+	return
+}