Implement block scopes (code inside braces)

- Putting code in between braces will create a new scope

src/ast.rs

@@ -113,6 +113,7 @@ pub struct If {
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Statement {
     Expr(Expression),
+    Block(BlockScope),
     Loop(Loop),
     If(If),
     Print(Expression),

src/astoptimizer.rs

@@ -18,6 +18,7 @@ impl SimpleAstOptimizer {
         for stmt in block {
             match stmt {
                 Statement::Expr(expr) => Self::optimize_expr(expr),
+                Statement::Block(block) => Self::optimize_block(block),
                 Statement::Loop(Loop {
                     condition,
                     advancement,

src/interpreter.rs

@@ -78,6 +78,10 @@ impl Interpreter {
                     self.resolve_expr(expr);
                 }
 
+                Statement::Block(block) => {
+                    self.run_block(block);
+                }
+
                 Statement::Loop(looop) => {
                     // loop runs as long condition != 0
                     loop {

src/parser.rs

@@ -50,6 +50,14 @@ impl<T: Iterator<Item = Token>> Parser<T> {
                 }
                 Token::EoF | Token::RBraces => break,
 
+                Token::LBraces => {
+                    self.next();
+                    prog.push(Statement::Block(self.parse_scoped_block()));
+                    if !matches!(self.next(), Token::RBraces) {
+                        panic!("Error parsing block: Expectected closing braces '}}'");
+                    }
+                }
+
                 // By default try to lex a statement
                 _ => prog.push(self.parse_stmt()),
             }