diff --git a/src/backend/interpreter.rs b/src/backend/interpreter.rs
index 99e4676..fa24c1f 100755
--- a/src/backend/interpreter.rs
+++ b/src/backend/interpreter.rs
@@ -2,8 +2,9 @@ use crate::{
     backend::environment::EnvironmentStack,
     common::{
         ast::{AstNode, Expr, NodeId},
-        base_value::{BaseValue, NativeFunction, Number, Truthy},
+        base_value::{BaseValue, NativeFunction, Number, Struct, Truthy},
         lox_result::{LoxError, LoxResult, runtime_error},
+        types::Type,
     },
     frontend::{source_registry::SourceSlice, tokens::TokenType},
 };
@@ -145,6 +146,13 @@ impl Interpreter {
                 }
                 Ok(ret)
             }
+            Expr::Struct { fields } => {
+                let fields: Vec<(String, Type)> = fields
+                    .iter()
+                    .map(|(name, ty)| (name.clone(), ty.clone()))
+                    .collect();
+                Ok(BaseValue::Struct(Box::new(Struct { fields })))
+            }
         };
         // Give location-less runtime errors this node's span.
         match result {
diff --git a/src/common/ast.rs b/src/common/ast.rs
index fdfab03..38fd0ad 100755
--- a/src/common/ast.rs
+++ b/src/common/ast.rs
@@ -2,8 +2,11 @@ use crate::{
     common::{base_value::BaseValue, types::Type},
     frontend::{source_registry::SourceSlice, tokens::TokenType},
 };
-use std::fmt::{Debug, Display};
 use std::sync::atomic::{AtomicUsize, Ordering};
+use std::{
+    collections::HashMap,
+    fmt::{Debug, Display},
+};
 
 /// A unique identity for an AST node, assigned once at construction.
 ///
@@ -23,7 +26,7 @@ impl NodeId {
     }
 }
 
-#[derive(Clone, PartialEq)]
+#[derive(Clone, PartialEq, Debug)]
 pub enum Expr {
     Literal {
         value: Box<BaseValue>,
@@ -83,6 +86,9 @@ pub enum Expr {
         increment: Box<AstNode>,
         body: Box<AstNode>,
     },
+    Struct {
+        fields: Box<HashMap<String, Type>>,
+    },
 }
 
 // Implementazione Display per Expr (per debugging)
@@ -164,100 +170,18 @@ impl std::fmt::Display for Expr {
                 "For({} = {} in {}) {{\n{}\n}}",
                 variable.node, condition.node, increment.node, body.node
             ),
+            Expr::Struct { fields } => {
+                let field_strs: Vec<String> = fields
+                    .iter()
+                    .map(|(k, v)| format!("{}: {:?}", k, v))
+                    .collect();
+                write!(f, "Struct {{ {} }}", field_strs.join(", "))
+            }
         }
     }
 }
 
-impl Debug for Expr {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Expr::Literal { value } => write!(f, "{:?} ", value,),
-            Expr::Binary {
-                left,
-                operator,
-                right,
-            } => write!(f, "({:?} {:?} {:?}) ", operator, left.node, right.node,),
-            Expr::Unary { operator, operand } => {
-                write!(f, "(Unary {:?} {:?}) ", operator, operand.node,)
-            }
-            Expr::Grouping { expression } => {
-                write!(f, "(Grouping {:?})", expression.node,)
-            }
-            Expr::Identifier { name } => {
-                write!(f, "(variable {:?})", name,)
-            }
-            Expr::Call { callee, arguments } => write!(
-                f,
-                "Call ({}({}))",
-                callee.node,
-                arguments
-                    .iter()
-                    .map(|arg| arg.node.to_string())
-                    .collect::<Vec<String>>()
-                    .join(", "),
-            ),
-            Expr::Assign { name, value } => {
-                write!(f, "(assign {:?} {:?})", name, value.node,)
-            }
-            Expr::If {
-                condition,
-                then_branch,
-                elif_branches,
-                else_branch,
-            } => {
-                let mut result =
-                    format!("IF ({:?}) {{\n{:?}\n}}", condition.node, then_branch.node,);
-                for (condition, branch) in elif_branches {
-                    result.push_str(&format!(
-                        " ELIF ({:?}) {{\n{:?}\n}}",
-                        condition.node, branch.node,
-                    ));
-                }
-                if let Some(else_branch) = else_branch {
-                    result.push_str(&format!(" ELSE {{\n{:?}\n}}", else_branch.node,));
-                }
-                write!(f, "IfStmt {:?}", result)
-            }
-            Expr::Print { expression } => {
-                write!(f, "Print({:?});", expression.node,)
-            }
-            Expr::VarDeclaration {
-                name,
-                initializer,
-                var_type,
-            } => match initializer {
-                Some(init) => write!(f, "Var({:?}: {:?} = {:?});", name, var_type, init.node,),
-                None => write!(f, "Var({:?}: {:?});", name, var_type,),
-            },
-            Expr::Return { expression, label } => {
-                write!(f, "Return({:?}, {}) ;", expression.node, label,)
-            }
-            Expr::Block { label, statements } => write!(
-                f,
-                "Block [{}] ([\n{:?}\n])",
-                label,
-                statements
-                    .iter()
-                    .map(|stmt| format!("{:?}", stmt.node))
-                    .collect::<Vec<_>>()
-                    .join("\t\t\n"),
-            ),
-            Expr::While { condition, body } => {
-                write!(f, "While({:?}) {{\n{:?}\n}}", condition.node, body.node,)
-            }
-            Expr::For {
-                variable,
-                condition,
-                increment,
-                body,
-            } => write!(
-                f,
-                "For({:?} = {:?} in {:?}) {{\n{:?}\n}} ",
-                variable.node, condition.node, increment.node, body.node,
-            ),
-        }
-    }
-}
+// Debug is derived on Expr via #[derive(Debug)] above.
 
 #[derive(Clone)]
 pub struct AstNode {
diff --git a/src/logging/display_ast.rs b/src/logging/display_ast.rs
index 1b24380..2460f49 100755
--- a/src/logging/display_ast.rs
+++ b/src/logging/display_ast.rs
@@ -414,6 +414,27 @@ impl PrettyPrint for Expr {
                 body.pretty_print(&ctx.child_context(true), f)?;
                 writeln!(f, "{}}}", ctx.child_context(true).indent())
             }
+            Expr::Struct { fields } => {
+                if ctx.config.compact {
+                    let field_strs: Vec<String> = fields
+                        .iter()
+                        .map(|(k, v)| format!("{}: {:?}", k, v))
+                        .collect();
+                    write!(f, "struct {{ {} }}", field_strs.join(", "))
+                } else {
+                    writeln!(f, "{}Struct {{", indent)?;
+                    for (name, ty) in fields.iter() {
+                        writeln!(
+                            f,
+                            "{}{}: {:?},",
+                            ctx.child_context(false).indent(),
+                            name,
+                            ty
+                        )?;
+                    }
+                    write!(f, "{}}}", indent)
+                }
+            }
         }
     }
 }
diff --git a/src/middleend/visit_ast.rs b/src/middleend/visit_ast.rs
index 75be11e..224154a 100644
--- a/src/middleend/visit_ast.rs
+++ b/src/middleend/visit_ast.rs
@@ -136,6 +136,8 @@ pub fn walk_expr<V: Visitor>(visitor: &mut V, expr: &AstNode) -> LoxResult<()> {
             visitor.visit_expr(increment)?;
             visitor.visit_expr(body)
         }
+        // Struct declarations carry only type information, no child expressions.
+        Expr::Struct { .. } => Ok(()),
     }
 }