main: Clear screen on mode change

src/main.rs

@@ -20,13 +20,17 @@ use std::{
     io::{IsTerminal, stdin},
 };
 
+fn clear() {
+    print!("\x1b[H\x1b[2J\x1b[3J");
+}
+
 fn main() -> Result<(), Box<dyn Error>> {
     if stdin().is_terminal() {
         read_and("\x1b[32m", ".>", " >", |line| match line.trim_end() {
             "" => Ok(Response::Continue),
             "exit" => Ok(Response::Break),
             "clear" => {
-                print!("\x1b[H\x1b[2J");
+                clear();
                 Ok(Response::Deny)
             }
             "lex" => {
@@ -66,6 +70,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 }
 
 fn lex() -> Result<(), Box<dyn Error>> {
+    clear();
     read_and("\x1b[93m", " >", "?>", |line| {
         let mut lexer = Lexer::new(line);
         if line.trim().is_empty() {
@@ -90,6 +95,7 @@ fn lex() -> Result<(), Box<dyn Error>> {
 }
 
 fn exprs() -> Result<(), Box<dyn Error>> {
+    clear();
     read_and("\x1b[93m", ".>", " >", |line| {
         let mut parser = Parser::new(Lexer::new(line));
         if line.trim().is_empty() {
@@ -113,6 +119,7 @@ fn exprs() -> Result<(), Box<dyn Error>> {
 }
 
 fn pats() -> Result<(), Box<dyn Error>> {
+    clear();
     read_and("\x1b[94m", " >", "?>", |line| {
         let mut parser = Parser::new(Lexer::new(line));
         if line.trim().is_empty() {
@@ -135,6 +142,7 @@ fn pats() -> Result<(), Box<dyn Error>> {
 }
 
 fn tys() -> Result<(), Box<dyn Error>> {
+    clear();
     read_and("\x1b[94m", ".>", " >", |line| {
         let mut parser = Parser::new(Lexer::new(line));
         if line.trim().is_empty() {