add decimal printer example program

programs/decimal_printer.mbl

@@ -0,0 +1,25 @@
+(decimal printer)
+ o
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+           o
+  (check if 0)
+v B-=-#01  <
+ v   * D-(div/10)
+v     B * <
+     o
+v> * 1    ^
+ F -R0* B(next digit, %10)
+*| # <-A vo(+48 = ascii)
+ |    #84 <
+ |       *-|
+ F         +B * B
+#<       \F----
+
+         *-|
+          P-
+         B

src/main.rs

@@ -1,4 +1,8 @@
-use std::{env, fs, io::{stdin, stdout, Write}, process::exit};
+use std::{
+	env, fs,
+	io::{stdin, stdout, Write},
+	process::exit,
+};
 
 use owo_colors::OwoColorize;
 
@@ -100,7 +104,6 @@ fn main() {
 		.unwrap_or_default();
 
 	let mut interpreter = Machine::new(&source, input_data);
-	print!("\x1B[2J"); // clear screen
 	interpreter.show();
 
 	loop {
@@ -139,7 +142,12 @@ q | quit | exit
 			["dbg" | "debug"] => {
 				dbg!(&interpreter);
 			}
-			["step", num] => _ = num.parse().map(|n| interpreter.step(n)),
+			["step", num] => {
+				if let Ok(n) = num.parse() {
+					interpreter.step(n);
+					interpreter.show();
+				}
+			}
 			["q" | "exit" | "quit"] => break,
 			["h" | "help" | "?"] => {
 				println!("{}", HELP_TEXT.green());
@@ -170,9 +178,8 @@ impl Machine {
 	}
 
 	fn show(&self) {
-		// dbg!(&self);
 		print!("\x1B[2J"); // clear screen
-		print!("\x1B[u"); // reset cursor
+		print!("\x1B[1;1H"); // reset cursor
 		for y in 0..self.grid.height() {
 			let mut marbles_on_row = Vec::new();
 			for x in 0..self.grid.width() {
@@ -423,7 +430,7 @@ impl Machine {
 						MathOp::Div => val_a.checked_div(val_b).unwrap_or_default(),
 						MathOp::Rem => val_a.checked_rem(val_b).unwrap_or_default(),
 					};
-					println!("{op:?} a:{val_a} b:{val_b}");
+					// println!("{op:?} a:{val_a} b:{val_b}");
 					*self.grid.get_mut(front_pos) = Tile::Marble { value: result, dir };
 					self.marbles.push(front_pos);
 				}