add loop examples

example/run.rs

@@ -1,15 +1,21 @@
 use std::{env::args, fs};
 
-use microlang::Context;
+use microlang::{Context, Value};
 
 pub fn main() {
 	unsafe { backtrace_on_stack_overflow::enable() };
 	let mut context = Context::empty();
-	let lines = fs::read_to_string(args().nth(1).expect("Pass a file as arg 1.")).expect("File could not be read.");
-	for line in lines.lines() {
-		match context.eval(line.into()) {
-			Err(err) => panic!("Failed : {err:?}"),
-			Ok((_, value)) => println!("{}", value.serialize()),
+	context.define_built("print", |values, _| {
+		for val in values {
+			print!("{} ", val.serialize());
 		}
+		println!();
+		Ok(Value::None)
+	});
+
+	let lines = fs::read_to_string(args().nth(1).expect("Pass a file as arg 1.")).expect("File could not be read.");
+	match context.eval(lines) {
+		Err(err) => panic!("Failed : {err:?}"),
+		Ok((_, value)) => println!("{}", value.serialize()),
 	}
 }