repline/repline.rs
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//! Prompts the user, reads the lines. Not much more to it than that.
//!
//! This module is in charge of parsing keyboard input and interpreting it for the line editor.
use crate::{editor::Editor, error::*, iter::*, raw::raw};
use std::{
collections::VecDeque,
io::{stdout, Bytes, Read, Result, Write},
};
/// Prompts the user, reads the lines. Not much more to it than that.
#[derive(Debug)]
pub struct Repline<'a, R: Read> {
input: Chars<Flatten<Result<u8>, Bytes<R>>>,
history: VecDeque<String>, // previous lines
hindex: usize, // current index into the history buffer
ed: Editor<'a>, // the current line buffer
}
impl<'a> Repline<'a, std::io::Stdin> {
pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
Self::with_input(std::io::stdin(), color, begin, again)
}
}
impl<'a, R: Read> Repline<'a, R> {
/// Constructs a [Repline] with the given [Reader](Read), color, begin, and again prompts.
pub fn with_input(input: R, color: &'a str, begin: &'a str, again: &'a str) -> Self {
Self {
input: Chars(Flatten(input.bytes())),
history: Default::default(),
hindex: 0,
ed: Editor::new(color, begin, again),
}
}
/// Set the terminal prompt color
pub fn set_color(&mut self, color: &'a str) {
self.ed.color = color
}
/// Append line to history and clear it
pub fn accept(&mut self) {
self.history_append(self.ed.to_string());
self.ed.clear();
self.hindex = self.history.len();
}
/// Clear the line
pub fn deny(&mut self) {
self.ed.clear()
}
/// Reads in a line, and returns it for validation
pub fn read(&mut self) -> ReplResult<String> {
const INDENT: &str = " ";
let mut stdout = stdout().lock();
let stdout = &mut stdout;
let _make_raw = raw();
// self.ed.begin_frame(stdout)?;
// self.ed.redraw_frame(stdout)?;
self.ed.print_head(stdout)?;
loop {
stdout.flush()?;
match self.input.next().ok_or(Error::EndOfInput)?? {
// Ctrl+C: End of Text. Immediately exits.
'\x03' => {
drop(_make_raw);
writeln!(stdout)?;
return Err(Error::CtrlC(self.ed.to_string()));
}
// Ctrl+D: End of Transmission. Ends the current line.
'\x04' => {
drop(_make_raw);
writeln!(stdout)?;
return Err(Error::CtrlD(self.ed.to_string()));
}
// Tab: extend line by 4 spaces
'\t' => {
self.ed.extend(INDENT.chars(), stdout)?;
}
// ignore newlines, process line feeds. Not sure how cross-platform this is.
'\n' => {}
'\r' => {
self.ed.push('\n', stdout)?;
return Ok(self.ed.to_string());
}
// Ctrl+Backspace in my terminal
'\x17' => {
self.ed.erase_word(stdout)?;
}
// Escape sequence
'\x1b' => self.escape(stdout)?,
// backspace
'\x08' | '\x7f' => {
let ed = &mut self.ed;
if ed.ends_with(INDENT.chars()) {
for _ in 0..INDENT.len() {
ed.pop(stdout)?;
}
} else {
ed.pop(stdout)?;
}
}
c if c.is_ascii_control() => {
if cfg!(debug_assertions) {
self.ed.extend(c.escape_debug(), stdout)?;
}
}
c => {
self.ed.push(c, stdout)?;
}
}
}
}
/// Prints a message without moving the cursor
pub fn print_inline(&mut self, value: impl std::fmt::Display) -> ReplResult<()> {
let mut stdout = stdout().lock();
self.print_err(&mut stdout, value)
}
/// Prints a message (ideally an error) without moving the cursor
fn print_err<W: Write>(&mut self, w: &mut W, value: impl std::fmt::Display) -> ReplResult<()> {
self.ed.print_err(w, value)
}
/// Handle ANSI Escape
fn escape<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
match self.input.next().ok_or(Error::EndOfInput)?? {
'[' => self.csi(w)?,
'O' => todo!("Process alternate character mode"),
other => self.ed.extend(other.escape_debug(), w)?,
}
Ok(())
}
/// Handle ANSI Control Sequence Introducer
fn csi<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
match self.input.next().ok_or(Error::EndOfInput)?? {
'A' => {
self.hindex = self.hindex.saturating_sub(1);
self.restore_history(w)?
}
'B' => {
self.hindex = self.hindex.saturating_add(1).min(self.history.len());
self.restore_history(w)?
}
'C' => self.ed.cursor_forward(1, w)?,
'D' => self.ed.cursor_back(1, w)?,
'H' => self.ed.home(w)?,
'F' => self.ed.end(w)?,
'3' => {
if let '~' = self.input.next().ok_or(Error::EndOfInput)?? {
let _ = self.ed.delete(w);
}
}
other => {
if cfg!(debug_assertions) {
self.ed.extend(other.escape_debug(), w)?;
}
}
}
Ok(())
}
/// Restores the currently selected history
fn restore_history<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
let Self { history, hindex, ed, .. } = self;
ed.undraw(w)?;
ed.clear();
ed.print_head(w)?;
if let Some(history) = history.get(*hindex) {
ed.extend(history.chars(), w)?
}
Ok(())
}
/// Append line to history
fn history_append(&mut self, mut buf: String) {
while buf.ends_with(char::is_whitespace) {
buf.pop();
}
if !self.history.contains(&buf) {
self.history.push_back(buf)
}
while self.history.len() > 20 {
self.history.pop_front();
}
}
}