96 lines
2.1 KiB
Rust
96 lines
2.1 KiB
Rust
//! This shows how an application can write on stderr
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//! instead of stdout, thus making it possible to
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//! the command API instead of the "old style" direct
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//! unbuffered API.
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//!
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//! This particular example is only suited to Unix
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//! for now.
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//!
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//! cargo run --example stderr
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use std::io;
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use crossterm::{
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cursor::{Hide, MoveTo, Show},
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event,
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event::{Event, KeyCode, KeyEvent},
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execute, queue,
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style::Print,
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terminal::{self, EnterAlternateScreen, LeaveAlternateScreen},
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};
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const TEXT: &str = r#"
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This screen is ran on stderr.
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And when you hit enter, it prints on stdout.
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This makes it possible to run an application and choose what will
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be sent to any application calling yours.
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For example, assuming you build this example with
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cargo build --bin stderr
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and then you run it with
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cd "$(target/debug/stderr)"
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what the application prints on stdout is used as argument to cd.
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Try it out.
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Hit any key to quit this screen:
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1 will print `..`
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2 will print `/`
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3 will print `~`
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Any other key will print this text (so that you may copy-paste)
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"#;
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fn run_app<W>(write: &mut W) -> io::Result<char>
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where
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W: io::Write,
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{
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queue!(
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write,
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EnterAlternateScreen, // enter alternate screen
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Hide // hide the cursor
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)?;
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let mut y = 1;
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for line in TEXT.split('\n') {
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queue!(write, MoveTo(1, y), Print(line.to_string()))?;
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y += 1;
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}
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write.flush()?;
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terminal::enable_raw_mode()?;
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let user_char = read_char()?; // we wait for the user to hit a key
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execute!(write, Show, LeaveAlternateScreen)?; // restore the cursor and leave the alternate screen
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terminal::disable_raw_mode()?;
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Ok(user_char)
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}
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pub fn read_char() -> io::Result<char> {
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loop {
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if let Event::Key(KeyEvent {
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code: KeyCode::Char(c),
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..
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}) = event::read()?
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{
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return Ok(c);
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}
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}
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}
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// cargo run --example stderr
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fn main() {
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match run_app(&mut io::stderr()).unwrap() {
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'1' => print!(".."),
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'2' => print!("/"),
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'3' => print!("~"),
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_ => println!("{}", TEXT),
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}
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}
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