331 lines
9.0 KiB
Go
331 lines
9.0 KiB
Go
package terminal
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import (
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"fmt"
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"unicode"
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"golang.org/x/text/width"
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)
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type RuneReader struct {
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stdio Stdio
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cursor *Cursor
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state runeReaderState
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}
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func NewRuneReader(stdio Stdio) *RuneReader {
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return &RuneReader{
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stdio: stdio,
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state: newRuneReaderState(stdio.In),
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}
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}
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func (rr *RuneReader) printChar(char rune, mask rune) {
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// if we don't need to mask the input
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if mask == 0 {
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// just print the character the user pressed
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fmt.Fprintf(rr.stdio.Out, "%c", char)
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} else {
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// otherwise print the mask we were given
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fmt.Fprintf(rr.stdio.Out, "%c", mask)
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}
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}
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func (rr *RuneReader) ReadLine(mask rune) ([]rune, error) {
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line := []rune{}
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// we only care about horizontal displacements from the origin so start counting at 0
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index := 0
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cursor := &Cursor{
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In: rr.stdio.In,
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Out: rr.stdio.Out,
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}
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// we get the terminal width and height (if resized after this point the property might become invalid)
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terminalSize, _ := cursor.Size(rr.Buffer())
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// we set the current location of the cursor once
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cursorCurrent, _ := cursor.Location(rr.Buffer())
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for {
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// wait for some input
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r, _, err := rr.ReadRune()
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if err != nil {
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return line, err
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}
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// increment cursor location
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cursorCurrent.X++
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// if the user pressed enter or some other newline/termination like ctrl+d
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if r == '\r' || r == '\n' || r == KeyEndTransmission {
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// delete what's printed out on the console screen (cleanup)
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for index > 0 {
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if cursorCurrent.CursorIsAtLineBegin() {
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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cursor.PreviousLine(1)
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cursor.Forward(int(terminalSize.X))
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cursorCurrent.X = terminalSize.X
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cursorCurrent.Y--
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} else {
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cursor.Back(1)
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cursorCurrent.X--
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}
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index--
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}
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// move the cursor the a new line
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cursor.MoveNextLine(cursorCurrent, terminalSize)
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// we're done processing the input
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return line, nil
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}
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// if the user interrupts (ie with ctrl+c)
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if r == KeyInterrupt {
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// go to the beginning of the next line
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fmt.Fprint(rr.stdio.Out, "\r\n")
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// we're done processing the input, and treat interrupt like an error
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return line, InterruptErr
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}
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// allow for backspace/delete editing of inputs
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if r == KeyBackspace || r == KeyDelete {
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// and we're not at the beginning of the line
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if index > 0 && len(line) > 0 {
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// if we are at the end of the word
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if index == len(line) {
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// just remove the last letter from the internal representation
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// also count the number of cells the rune before the cursor occupied
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cells := runeWidth(line[len(line)-1])
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line = line[:len(line)-1]
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// go back one
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if cursorCurrent.X == 1 {
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cursor.PreviousLine(1)
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cursor.Forward(int(terminalSize.X))
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} else {
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cursor.Back(cells)
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}
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// clear the rest of the line
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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} else {
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// we need to remove a character from the middle of the word
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cells := runeWidth(line[index-1])
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// remove the current index from the list
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line = append(line[:index-1], line[index:]...)
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// save the current position of the cursor, as we have to move the cursor one back to erase the current symbol
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// and then move the cursor for each symbol in line[index-1:] to print it out, afterwards we want to restore
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// the cursor to its previous location.
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cursor.Save()
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// clear the rest of the line
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cursor.Back(cells)
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// print what comes after
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for _, char := range line[index-1:] {
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//Erase symbols which are left over from older print
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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// print characters to the new line appropriately
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rr.printChar(char, mask)
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}
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// erase what's left over from last print
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if cursorCurrent.Y < terminalSize.Y {
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cursor.NextLine(1)
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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}
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// restore cursor
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cursor.Restore()
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if cursorCurrent.CursorIsAtLineBegin() {
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cursor.PreviousLine(1)
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cursor.Forward(int(terminalSize.X))
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} else {
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cursor.Back(cells)
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}
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}
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// decrement the index
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index--
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} else {
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// otherwise the user pressed backspace while at the beginning of the line
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soundBell(rr.stdio.Out)
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}
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// we're done processing this key
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continue
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}
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// if the left arrow is pressed
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if r == KeyArrowLeft {
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// if we have space to the left
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if index > 0 {
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//move the cursor to the prev line if necessary
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if cursorCurrent.CursorIsAtLineBegin() {
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cursor.PreviousLine(1)
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cursor.Forward(int(terminalSize.X))
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} else {
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cursor.Back(runeWidth(line[index-1]))
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}
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//decrement the index
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index--
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} else {
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// otherwise we are at the beginning of where we started reading lines
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// sound the bell
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soundBell(rr.stdio.Out)
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}
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// we're done processing this key press
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continue
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}
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// if the right arrow is pressed
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if r == KeyArrowRight {
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// if we have space to the right
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if index < len(line) {
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// move the cursor to the next line if necessary
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if cursorCurrent.CursorIsAtLineEnd(terminalSize) {
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cursor.NextLine(1)
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} else {
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cursor.Forward(runeWidth(line[index]))
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}
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index++
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} else {
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// otherwise we are at the end of the word and can't go past
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// sound the bell
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soundBell(rr.stdio.Out)
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}
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// we're done processing this key press
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continue
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}
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// the user pressed one of the special keys
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if r == SpecialKeyHome {
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for index > 0 {
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if cursorCurrent.CursorIsAtLineBegin() {
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cursor.PreviousLine(1)
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cursor.Forward(int(terminalSize.X))
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cursorCurrent.X = terminalSize.X
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cursorCurrent.Y--
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} else {
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cursor.Back(runeWidth(line[index-1]))
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cursorCurrent.X--
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}
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index--
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}
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continue
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// user pressed end
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} else if r == SpecialKeyEnd {
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for index != len(line) {
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if cursorCurrent.CursorIsAtLineEnd(terminalSize) {
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cursor.NextLine(1)
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cursorCurrent.X = COORDINATE_SYSTEM_BEGIN
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cursorCurrent.Y++
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} else {
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cursor.Forward(runeWidth(line[index]))
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cursorCurrent.X++
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}
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index++
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}
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continue
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// user pressed forward delete key
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} else if r == SpecialKeyDelete {
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// if index at the end of the line nothing to delete
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if index != len(line) {
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// save the current position of the cursor, as we have to erase the current symbol
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// and then move the cursor for each symbol in line[index:] to print it out, afterwards we want to restore
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// the cursor to its previous location.
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cursor.Save()
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// remove the symbol after the cursor
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line = append(line[:index], line[index+1:]...)
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// print the updated line
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for _, char := range line[index:] {
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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// print out the character
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rr.printChar(char, mask)
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}
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// erase what's left on last line
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if cursorCurrent.Y < terminalSize.Y {
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cursor.NextLine(1)
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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}
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// restore cursor
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cursor.Restore()
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if len(line) == 0 || index == len(line) {
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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}
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}
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continue
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}
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// if the letter is another escape sequence
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if unicode.IsControl(r) || r == IgnoreKey {
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// ignore it
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continue
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}
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// the user pressed a regular key
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// if we are at the end of the line
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if index == len(line) {
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// just append the character at the end of the line
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line = append(line, r)
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// save the location of the cursor
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index++
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// print out the character
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rr.printChar(r, mask)
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} else {
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// we are in the middle of the word so we need to insert the character the user pressed
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line = append(line[:index], append([]rune{r}, line[index:]...)...)
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// save the current position of the cursor, as we have to move the cursor back to erase the current symbol
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// and then move for each symbol in line[index:] to print it out, afterwards we want to restore
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// cursor's location to its previous one.
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cursor.Save()
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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// remove the symbol after the cursor
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// print the updated line
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for _, char := range line[index:] {
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EraseLine(rr.stdio.Out, ERASE_LINE_END)
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// print out the character
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rr.printChar(char, mask)
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cursorCurrent.X++
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}
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// if we are at the last line, we want to visually insert a new line and append to it.
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if cursorCurrent.CursorIsAtLineEnd(terminalSize) && cursorCurrent.Y == terminalSize.Y {
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// add a new line to the terminal
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fmt.Fprintln(rr.stdio.Out)
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// restore the position of the cursor horizontally
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cursor.Restore()
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// restore the position of the cursor vertically
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cursor.PreviousLine(1)
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} else {
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// restore cursor
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cursor.Restore()
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}
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// check if cursor needs to move to next line
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cursorCurrent, _ = cursor.Location(rr.Buffer())
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if cursorCurrent.CursorIsAtLineEnd(terminalSize) {
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cursor.NextLine(1)
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} else {
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cursor.Forward(runeWidth(r))
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}
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// increment the index
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index++
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}
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}
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}
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func runeWidth(r rune) int {
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switch width.LookupRune(r).Kind() {
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case width.EastAsianWide, width.EastAsianFullwidth:
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return 2
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}
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return 1
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}
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