Basic clear

src/engine.rs

@@ -2,10 +2,10 @@ use std::io::{Stdout, Write};
 use std::ops::Deref;
 
 use crossterm::{
-    cursor::{MoveToColumn, RestorePosition, SavePosition},
+    cursor::{MoveTo, MoveToColumn, RestorePosition, SavePosition},
     event::{read, Event, KeyCode, KeyEvent, KeyModifiers},
     style::{Color, Print, ResetColor, SetForegroundColor},
-    terminal::{Clear, ClearType},
+    terminal::{self, Clear, ClearType},
     QueueableCommand, Result,
 };
 
@@ -60,6 +60,7 @@ pub enum Signal {
     Success(String),
     CtrlC, // Interrupt current editing
     CtrlD, // End terminal session
+    CtrlL, // FormFeed/Clear current screen
 }
 
 pub fn print_message(stdout: &mut Stdout, msg: &str) -> Result<()> {
@@ -81,6 +82,16 @@ pub fn print_crlf(stdout: &mut Stdout) -> Result<()> {
     Ok(())
 }
 
+pub fn clear_screen(stdout: &mut Stdout) -> Result<()> {
+    let (_, num_lines) = terminal::size()?;
+    for _ in 0..2 * num_lines {
+        stdout.queue(Print("\n"))?;
+    }
+    stdout.queue(MoveTo(0, 0))?;
+    stdout.flush()?;
+    Ok(())
+}
+
 fn queue_prompt(stdout: &mut Stdout) -> Result<()> {
     // print our prompt
     stdout
@@ -436,7 +447,11 @@ impl Engine {
     }
 
     pub fn read_line(&mut self, stdout: &mut Stdout) -> Result<Signal> {
-        queue_prompt(stdout)?;
+        if self.history_search.is_some() {
+            history_search_paint(stdout, &self)?;
+        } else {
+            buffer_paint(stdout, &self)?;
+        }
         stdout.flush()?;
 
         loop {
@@ -477,6 +492,9 @@ impl Engine {
                         self.run_edit_commands(&[EditCommand::Clear]);
                         return Ok(Signal::CtrlC);
                     }
+                    KeyCode::Char('l') => {
+                        return Ok(Signal::CtrlL);
+                    }
                     KeyCode::Char('h') => {
                         self.run_edit_commands(&[EditCommand::Backspace]);
                     }

src/main.rs

@@ -6,7 +6,7 @@ use std::io::stdout;
 mod line_buffer;
 
 mod engine;
-use engine::{print_crlf, print_message, Engine, Signal};
+use engine::{clear_screen, print_crlf, print_message, Engine, Signal};
 
 mod diagnostic;
 use diagnostic::print_events;
@@ -40,12 +40,19 @@ fn main() -> Result<()> {
                     if (buffer.trim() == "exit") || (buffer.trim() == "logout") {
                         break;
                     }
+                    if buffer.trim() == "clear" {
+                        clear_screen(&mut stdout)?;
+                        continue;
+                    }
                     print_message(&mut stdout, &format!("Our buffer: {}", buffer))?;
                 }
                 Signal::CtrlC => {
                     // We need to move one line down to start with the prompt on a new line
                     print_crlf(&mut stdout)?;
                 }
+                Signal::CtrlL => {
+                    clear_screen(&mut stdout)?;
+                }
             }
         }
     }