352 lines
8.8 KiB
V
352 lines
8.8 KiB
V
// Copyright (c) 2019 Alexander Medvednikov. All rights reserved.
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// Use of this source code is governed by an MIT license
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// that can be found in the LICENSE file.
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// Linux version
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// Will serve as more advanced input method
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// Based on the work of https://github.com/AmokHuginnsson/replxx
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module readline
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import term
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#include <termios.h>
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#include <sys/ioctl.h>
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// Used to change the terminal options
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struct termios {
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mut:
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c_iflag int
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c_oflag int
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c_cflag int
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c_lflag int
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c_cc [12]int //NCCS == 12. Cant use the defined value here
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}
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// Used to collect the screen informations
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struct winsize {
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ws_row u16
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ws_col u16
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ws_xpixel u16
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ws_ypixel u16
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}
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struct Readline {
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mut:
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is_raw bool
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orig_termios termios
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current string // Line being edited
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cursor int // Cursor position
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overwrite bool
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cursor_row_offset int
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}
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// Defines actions to execute
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enum Action {
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eof
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nothing
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insert_character
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commit_line
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delete_left
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delete_right
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move_cursor_left
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move_cursor_right
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move_cursor_begining
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move_cursor_end
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move_cursor_word_left
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move_cursor_word_right
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history_previous
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history_next
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overwrite
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clear_screen
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}
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// Toggle raw mode of the terminal by changing its attributes
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pub fn (r mut Readline) enable_raw_mode() {
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if ( C.tcgetattr(0, &r.orig_termios) == -1 ) {
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panic('No tty')
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}
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mut raw := r.orig_termios
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raw.c_iflag &= ~( C.BRKINT | C.ICRNL | C.INPCK | C.ISTRIP | C.IXON )
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raw.c_cflag |= ( C.CS8 )
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raw.c_lflag &= ~( C.ECHO | C.ICANON | C.IEXTEN | C.ISIG )
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raw.c_cc[C.VMIN] = 1
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raw.c_cc[C.VTIME] = 0
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C.tcsetattr(0, C.TCSADRAIN, &raw)
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r.is_raw = true
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}
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// Not catching the SIGUSER (CTRL+C) Signal
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pub fn (r Readline) enable_raw_mode2() {
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if ( C.tcgetattr(0, &r.orig_termios) == -1 ) {
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panic('No tty')
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}
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mut raw := r.orig_termios
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raw.c_iflag &= ~( C.BRKINT | C.ICRNL | C.INPCK | C.ISTRIP | C.IXON )
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raw.c_cflag |= ( C.CS8 )
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raw.c_lflag &= ~( C.ECHO | C.ICANON | C.IEXTEN )
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raw.c_cc[C.VMIN] = 1
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raw.c_cc[C.VTIME] = 0
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C.tcsetattr(0, C.TCSADRAIN, &raw)
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}
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// Reset back the terminal to its default value
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pub fn (r Readline) disable_raw_mode() {
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if r.is_raw {
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C.tcsetattr(0, C.TCSADRAIN, &r.orig_termios)
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}
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}
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// Read single char
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// TODO: Maybe handle UNICODE
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fn (r Readline) read_char() byte {
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return C.getchar()
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}
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// Main function of the readline module
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// Will loop and ingest characters until EOF or Enter
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// Returns the completed line
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pub fn (r mut Readline) read_line() string {
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r.current = ''
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r.cursor = 0
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for {
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c := r.read_char()
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a := r.analyse(c)
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if r.execute(a, c) {
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break
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}
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}
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return r.current
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}
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fn (r Readline) analyse(c byte) Action {
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switch c {
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case `\0`: return Action.eof
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case 0x3 : return Action.eof // End of Text
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case 0x4 : return Action.eof // End of Transmission
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case 255 : return Action.eof
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case `\n`: return Action.commit_line
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case `\r`: return Action.commit_line
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case `\f`: return Action.clear_screen // CTRL + L
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case `\b`: return Action.delete_left // Backspace
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case 127 : return Action.delete_left // DEL
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case 27 : return r.analyse_control() // ESC
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case 1 : return Action.move_cursor_begining // ^A
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case 5 : return Action.move_cursor_end // ^E
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default : return Action.insert_character
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}
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}
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fn (r Readline) analyse_control() Action {
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c := r.read_char()
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switch c {
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case `[`:
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sequence := r.read_char()
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switch sequence {
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case `C`: return Action.move_cursor_right
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case `D`: return Action.move_cursor_left
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case `E`: return Action.history_next
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case `F`: return Action.history_previous
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case `1`: return r.analyse_extended_control()
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case `3`: return r.analyse_extended_control_no_eat()
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}
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}
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return Action.nothing
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}
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fn (r Readline) analyse_extended_control() Action {
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r.read_char() // Removes ;
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c := r.read_char()
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switch c {
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case `5`:
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direction := r.read_char()
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switch direction {
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case `C`: return Action.move_cursor_word_right
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case `D`: return Action.move_cursor_word_left
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}
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}
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return Action.nothing
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}
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fn (r Readline) analyse_extended_control_no_eat() Action {
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c := r.read_char()
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switch c {
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case `~`: return Action.delete_right // Suppr key
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}
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return Action.nothing
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}
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fn (r mut Readline) execute(a Action, c byte) bool {
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switch a {
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case Action.eof: return true
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case Action.insert_character: r.insert_character(c)
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case Action.commit_line: return r.commit_line()
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case Action.delete_left: r.delete_character()
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case Action.delete_right: r.suppr_character()
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case Action.move_cursor_left: r.move_cursor_left()
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case Action.move_cursor_right: r.move_cursor_right()
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case Action.move_cursor_begining: r.move_cursor_begining()
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case Action.move_cursor_end: r.move_cursor_end()
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case Action.move_cursor_word_left: r.move_cursor_word_left()
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case Action.move_cursor_word_right: r.move_cursor_word_right()
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case Action.clear_screen: r.clear_screen()
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}
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return false
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}
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fn get_screen_columns() int {
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ws := winsize{}
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cols := if C.ioctl(1, C.TIOCGWINSZ, &ws) == -1 { 80 } else { ws.ws_col }
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return int(cols)
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}
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fn shift_cursor(xpos int, yoffset int) {
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if yoffset != 0 {
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if yoffset > 0 {
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term.cursor_down(yoffset)
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}
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else {
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term.cursor_up(- yoffset)
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}
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}
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// Absolute X position
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print('\x1b[${xpos + 1}G')
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}
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fn calculate_screen_position(x_in int, y_in int, screen_columns int, char_count int, out mut []int) {
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mut x := x_in
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mut y := y_in
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out[0] = x
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out[1] = y
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for chars_remaining := char_count; chars_remaining > 0; {
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chars_this_row := if ( (x + chars_remaining) < screen_columns) { chars_remaining } else { screen_columns - x }
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out[0] = x + chars_this_row
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out[1] = y
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chars_remaining -= chars_this_row
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x = 0
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y++
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}
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if out[0] == screen_columns {
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out[0] = 0
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out[1]++
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}
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}
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// Will redraw the line
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fn (r mut Readline) refresh_line() {
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mut end_of_input := [0, 0]
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calculate_screen_position(0, 0, get_screen_columns(), r.current.len, mut end_of_input)
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end_of_input[1] += r.current.count('\n')
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mut cursor_pos := [0, 0]
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calculate_screen_position(0, 0, get_screen_columns(), r.cursor, mut cursor_pos)
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shift_cursor(0, -r.cursor_row_offset)
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term.erase_toend()
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print(r.current)
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if end_of_input[0] == 0 && end_of_input[1] > 0 {
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print('\n')
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}
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shift_cursor(cursor_pos[0], - (end_of_input[1] - cursor_pos[1]))
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r.cursor_row_offset = cursor_pos[1]
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}
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fn (r mut Readline) insert_character(c byte) {
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// Small ASCII, to expand
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if c >= 127 {
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return
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}
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// TODO: Add character if overwrite at end
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if !r.overwrite {
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r.current = r.current.left(r.cursor) + c.str() + r.current.right(r.cursor)
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} else {
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// Overwriting
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}
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r.cursor++
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// Simply print new character if at end of line
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// Otherwise refresh the line if cursor != r.current.len
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if r.cursor == r.current.len && r.current.len < get_screen_columns() {
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print(c.str())
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} else {
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r.refresh_line()
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}
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}
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// Removes the character behind cursor.
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fn (r mut Readline) delete_character() {
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if r.cursor <= 0 {
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return
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}
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r.cursor--
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r.current = r.current.left(r.cursor) + r.current.right(r.cursor + 1)
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r.refresh_line()
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}
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// Removes the character in front of cursor.
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fn (r mut Readline) suppr_character() {
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if r.cursor > r.current.len {
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return
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}
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r.current = r.current.left(r.cursor) + r.current.right(r.cursor + 1)
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r.refresh_line()
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}
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// Add a line break then stops the main loop
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fn (r mut Readline) commit_line() bool {
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r.current = r.current + '\n'
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return true
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}
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fn (r mut Readline) move_cursor_left() {
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if r.cursor > 0 {
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r.cursor--
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r.refresh_line()
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}
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}
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fn (r mut Readline) move_cursor_right() {
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if r.cursor < r.current.len {
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r.cursor++
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r.refresh_line()
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}
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}
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fn (r mut Readline) move_cursor_begining() {
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r.cursor = 0
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r.refresh_line()
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}
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fn (r mut Readline) move_cursor_end() {
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r.cursor = r.current.len
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r.refresh_line()
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}
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// Check if the character is considered as a word-breaking character
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fn (r Readline) is_break_character(c byte) bool {
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break_characters := ' \t\v\f\a\b\r\n`~!@#$%^&*()-=+[{]}\\|;:\'",<.>/?'
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return break_characters.contains(c.str())
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}
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fn (r mut Readline) move_cursor_word_left() {
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if r.cursor > 0 {
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for ; r.cursor > 0 && r.is_break_character(r.current[r.cursor - 1]); r.cursor-- {}
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for ; r.cursor > 0 && !r.is_break_character(r.current[r.cursor - 1]); r.cursor-- {}
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r.refresh_line()
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}
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}
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fn (r mut Readline) move_cursor_word_right() {
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if r.cursor < r.current.len {
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for ; r.cursor < r.current.len && r.is_break_character(r.current[r.cursor]); r.cursor++ {}
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for ; r.cursor < r.current.len && !r.is_break_character(r.current[r.cursor]); r.cursor++ {}
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r.refresh_line()
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}
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}
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fn (r mut Readline) clear_screen() {
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term.set_cursor_position(1, 1)
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term.erase_clear()
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r.refresh_line()
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}
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