add loop examples

example/data/hello_world.mc

@@ -0,0 +1,4 @@
+
+let msg = "hello world";
+
+msg

example/data/loops.mc

@@ -0,0 +1,22 @@
+
+let i = 0;
+
+loop {
+    i = i + 1;
+    print("i", i);
+    if (i > 5) break;
+}
+
+fn for(array, op) {
+    let index = 0;
+    loop {
+        let item = array[index];
+        if (item == none) break;
+        op(item, index);
+        index = index + 1;
+    }
+}
+
+for([1, 2, 3], (item, index) => {
+    print("at index", index, "item", item);
+});

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()),
 	}
 }