161 lines
3.3 KiB
Go
161 lines
3.3 KiB
Go
package textmanip
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import "unicode"
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type Dot struct { Start, End int }
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func EmptyDot (position int) Dot {
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return Dot { position, position }
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}
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func (dot Dot) Canon () Dot {
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if dot.Start > dot.End {
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return Dot { dot.End, dot.Start }
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} else {
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return dot
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}
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}
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func (dot Dot) Empty () bool {
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return dot.Start == dot.End
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}
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func (dot Dot) Add (delta int) Dot {
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return Dot {
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dot.Start + delta,
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dot.End + delta,
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}
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}
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func (dot Dot) Sub (delta int) Dot {
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return Dot {
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dot.Start - delta,
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dot.End - delta,
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}
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}
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func WordToLeft (text []rune, dot Dot) (length int) {
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cursor := dot.End
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if cursor < 1 { return }
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if cursor > len(text) { cursor = len(text) }
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index := cursor - 1
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for index >= 0 && unicode.IsSpace(text[index]) {
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length ++
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index --
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}
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for index >= 0 && !unicode.IsSpace(text[index]) {
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length ++
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index --
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}
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return
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}
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func WordToRight (text []rune, dot Dot) (length int) {
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cursor := dot.End
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if cursor < 0 { return }
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if cursor > len(text) { cursor = len(text) }
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index := cursor
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for index < len(text) && unicode.IsSpace(text[index]) {
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length ++
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index ++
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}
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for index < len(text) && !unicode.IsSpace(text[index]) {
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length ++
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index ++
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}
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return
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}
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func Backspace (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
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if dot.Empty() {
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cursor := dot.End
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if cursor < 1 { return text, dot }
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if cursor > len(text) { cursor = len(text) }
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distance := 1
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if word {
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distance = WordToLeft(text, dot)
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}
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result = append(result, text[:cursor - distance]...)
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result = append(result, text[cursor:]...)
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moved = EmptyDot(cursor - distance)
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} else {
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return Delete(text, dot, word)
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}
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return
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}
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func Delete (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
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if dot.Empty() {
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cursor := dot.End
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if cursor < 0 { return text, dot }
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if cursor > len(text) { cursor = len(text) }
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distance := 1
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if word {
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distance = WordToRight(text, dot)
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}
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result = append(result, text[:cursor]...)
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result = append(result, text[cursor + distance:]...)
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moved = dot
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return
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} else {
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result = append(result, text[:dot.Start]...)
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result = append(result, text[dot.End:]...)
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moved = EmptyDot(dot.Start)
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return
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}
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}
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func Type (text []rune, dot Dot, character rune) (result []rune, moved Dot) {
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if dot.Empty() {
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cursor := dot.End
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if cursor < 0 { cursor = 0 }
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if cursor > len(text) { cursor = len(text) }
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result = append(result, text[:cursor]...)
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result = append(result, character)
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if cursor < len(text) {
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result = append(result, text[cursor:]...)
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}
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moved = EmptyDot(cursor + 1)
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return
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} else {
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result = append(result, text[:dot.Start]...)
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result = append(result, character)
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result = append(result, text[dot.End:]...)
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moved = EmptyDot(dot.Start)
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return
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}
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}
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func MoveLeft (text []rune, dot Dot, word bool) (moved Dot) {
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cursor := dot.Start
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if cursor < 1 { return EmptyDot(cursor) }
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if cursor > len(text) { cursor = len(text) }
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distance := 1
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if word {
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distance = WordToLeft(text, dot)
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}
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moved = EmptyDot(cursor - distance)
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return
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}
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func MoveRight (text []rune, dot Dot, word bool) (moved Dot) {
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cursor := dot.End
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if cursor < 0 { return EmptyDot(cursor) }
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if cursor > len(text) { cursor = len(text) }
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distance := 1
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if word {
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distance = WordToRight(text, dot)
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}
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moved = EmptyDot(cursor + distance)
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return
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}
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