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externrefexternref
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add a nano like terminal based text editor
1 parent 09f1335 commit b4bce3c

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4 files changed

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‎src/editor/display.rs‎

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use crate::editor::editor::Editor;
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use crossterm::{
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cursor, execute,
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style::{Color, Print, ResetColor, SetForegroundColor},
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terminal::ClearType,
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};
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use std::io::{self, stdout, Write};
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pub struct Display;
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impl Display {
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pub fn new() -> Self {
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Display
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}
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pub fn refresh_screen(&mut self, editor: &Editor) -> io::Result<()> {
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execute!(stdout(), cursor::Hide)?;
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execute!(stdout(), cursor::MoveTo(0, 0))?;
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let display_lines = if editor.terminal_height > 2 {
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editor.terminal_height - 2
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} else {
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0
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};
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for i in 0..display_lines {
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let line_index = editor.offset_y + i;
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if line_index < editor.content.len() {
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let line = &editor.content[line_index];
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let display_line = if line.len() > editor.terminal_width {
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&line[..editor.terminal_width]
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} else {
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line
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};
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execute!(
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stdout(),
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Print(format!(
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"{:<width$}",
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display_line,
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width = editor.terminal_width
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))
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)?;
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} else {
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execute!(
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stdout(),
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Print(format!("{:<width$}", "~", width = editor.terminal_width))
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)?;
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}
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execute!(
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stdout(),
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crossterm::terminal::Clear(ClearType::UntilNewLine)
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)?;
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execute!(stdout(), Print("\r\n"))?;
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}
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self.draw_status_bar(editor)?;
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self.draw_help_bar(editor)?;
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let screen_y = editor.cursor_y - editor.offset_y;
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let display_x = if editor.cursor_x > 0 && editor.terminal_width > 0 && editor.cursor_x >= editor.terminal_width {
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editor.terminal_width.saturating_sub(1)
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} else {
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editor.cursor_x
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};
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execute!(stdout(), cursor::MoveTo(display_x as u16, screen_y as u16))?;
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execute!(stdout(), cursor::Show)?;
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stdout().flush()?;
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Ok(())
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}
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fn draw_status_bar(&self, editor: &Editor) -> io::Result<()> {
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execute!(stdout(), SetForegroundColor(Color::Black))?;
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execute!(stdout(), crossterm::style::SetBackgroundColor(Color::White))?;
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let status = format!(
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" {} | Line {}/{} | Col {} {}",
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editor.filename.as_deref().unwrap_or("New File"),
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editor.cursor_y + 1,
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editor.content.len(),
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editor.cursor_x + 1,
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if editor.modified { "[Modified]" } else { "" }
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);
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let truncated_status = if status.len() > editor.terminal_width {
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&status[..editor.terminal_width]
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} else {
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&status
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};
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execute!(
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stdout(),
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Print(format!(
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"{:<width$}",
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truncated_status,
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width = editor.terminal_width
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))
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)?;
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execute!(stdout(), ResetColor)?;
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Ok(())
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}
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fn draw_help_bar(&self, editor: &Editor) -> io::Result<()> {
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execute!(stdout(), Print("\r\n"))?;
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execute!(stdout(), SetForegroundColor(Color::DarkGrey))?;
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let help = "^X Exit ^S Save ^O Open Arrow keys to move";
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let truncated_help = if help.len() > editor.terminal_width {
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&help[..editor.terminal_width]
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} else {
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help
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};
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execute!(stdout(), Print(truncated_help))?;
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execute!(stdout(), ResetColor)?;
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Ok(())
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}
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}

‎src/editor/editor.rs‎

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use crossterm::{
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cursor,
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event::{self, Event, KeyEventKind},
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execute,
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terminal::{self, ClearType},
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};
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use std::fs;
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use std::io::{self, stdout};
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use std::path::Path;
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use crate::editor::display::Display;
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use crate::editor::input::InputHandler;
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pub struct Editor {
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pub content: Vec<String>,
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pub cursor_x: usize,
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pub cursor_y: usize,
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pub offset_y: usize,
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pub filename: Option<String>,
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pub modified: bool,
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pub terminal_height: usize,
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pub terminal_width: usize,
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}
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impl Editor {
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pub fn new() -> io::Result<Self> {
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let (width, height) = terminal::size()?;
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Ok(Editor {
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content: vec![String::new()],
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cursor_x: 0,
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cursor_y: 0,
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offset_y: 0,
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filename: None,
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modified: false,
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terminal_height: height as usize,
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terminal_width: width as usize,
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})
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}
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pub fn open_file(filename: &str) -> io::Result<Self> {
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let mut editor = Self::new()?;
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editor.filename = Some(filename.to_string());
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if Path::new(filename).exists() {
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let content = fs::read_to_string(filename)?;
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editor.content = if content.is_empty() {
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vec![String::new()]
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} else {
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content.lines().map(|s| s.to_string()).collect()
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};
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}
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Ok(editor)
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}
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pub fn run(&mut self) -> io::Result<()> {
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terminal::enable_raw_mode()?;
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execute!(stdout(), terminal::Clear(ClearType::All))?;
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let mut input_handler = InputHandler::new();
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loop {
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let display_result = {
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let mut display = Display::new();
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display.refresh_screen(self)
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};
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display_result?;
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if let Event::Key(key_event) = event::read()? {
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if key_event.kind == KeyEventKind::Press {
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if input_handler.process_key(self, key_event)? {
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break;
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}
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}
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}
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}
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terminal::disable_raw_mode()?;
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execute!(stdout(), terminal::Clear(ClearType::All))?;
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execute!(stdout(), cursor::MoveTo(0, 0))?;
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Ok(())
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}
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pub fn clamp_cursor_x(&mut self) {
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let line_len = self.content[self.cursor_y].len();
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if self.cursor_x > line_len {
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self.cursor_x = line_len;
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}
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}
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pub fn insert_char(&mut self, c: char) {
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self.content[self.cursor_y].insert(self.cursor_x, c);
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self.cursor_x += 1;
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self.modified = true;
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}
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pub fn insert_newline(&mut self) {
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let current_line = &self.content[self.cursor_y];
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let new_line = current_line[self.cursor_x..].to_string();
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self.content[self.cursor_y].truncate(self.cursor_x);
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self.content.insert(self.cursor_y + 1, new_line);
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self.cursor_y += 1;
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self.cursor_x = 0;
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self.modified = true;
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}
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pub fn delete_char(&mut self) {
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if self.cursor_x > 0 {
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self.content[self.cursor_y].remove(self.cursor_x - 1);
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self.cursor_x -= 1;
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self.modified = true;
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} else if self.cursor_y > 0 {
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let current_line = self.content.remove(self.cursor_y);
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self.cursor_y -= 1;
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self.cursor_x = self.content[self.cursor_y].len();
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self.content[self.cursor_y].push_str(&current_line);
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self.modified = true;
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}
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}
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pub fn delete_char_forward(&mut self) {
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if self.cursor_x < self.content[self.cursor_y].len() {
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self.content[self.cursor_y].remove(self.cursor_x);
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self.modified = true;
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} else if self.cursor_y < self.content.len().saturating_sub(1) {
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let next_line = self.content.remove(self.cursor_y + 1);
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self.content[self.cursor_y].push_str(&next_line);
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self.modified = true;
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}
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}
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pub fn move_cursor_up(&mut self) {
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if self.cursor_y > 0 {
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self.cursor_y -= 1;
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if self.cursor_y < self.offset_y {
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self.offset_y = self.cursor_y;
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}
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self.clamp_cursor_x();
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}
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}
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pub fn move_cursor_down(&mut self) {
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if self.cursor_y < self.content.len().saturating_sub(1) {
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self.cursor_y += 1;
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// Prevent overflow by checking if terminal_height is large enough
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if self.terminal_height > 2 && self.cursor_y >= self.offset_y + self.terminal_height - 2 {
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self.offset_y = self.cursor_y.saturating_sub(self.terminal_height - 3);
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}
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self.clamp_cursor_x();
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}
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}
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pub fn move_cursor_left(&mut self) {
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if self.cursor_x > 0 {
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self.cursor_x -= 1;
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} else if self.cursor_y > 0 {
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self.cursor_y -= 1;
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self.cursor_x = self.content[self.cursor_y].len();
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}
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}
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pub fn move_cursor_right(&mut self) {
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if self.cursor_x < self.content[self.cursor_y].len() {
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self.cursor_x += 1;
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} else if self.cursor_y < self.content.len() - 1 {
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self.cursor_y += 1;
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self.cursor_x = 0;
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}
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}
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}
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pub fn start_editor(filename: Option<&str>) -> io::Result<()> {
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let mut editor = if let Some(file) = filename {
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Editor::open_file(file)?
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} else {
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Editor::new()?
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};
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editor.run()
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}

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