feat: Implement AST binder and VM

Adds a new `Binder` struct that traverses the AST and resolves variable
references to concrete `Address` types (Local, Upvalue, Global). This
information is crucial for the Virtual Machine's execution phase.

Introduces the `BoundKind` enum to represent the AST after binding.

The `VM` is updated to handle `BoundKind` nodes and execute the bound
AST.
It now manages a call stack, local variables, and closures for function
calls and upvalue capturing.

The `Environment` struct is enhanced to manage global variables and
provide
a unified interface for parsing, binding, and executing scripts. It also
includes basic standard library functions.

src/main.rs

@@ -1,4 +1,5 @@
 use eframe::egui;
+use crate::ast::environment::Environment;
 
 pub mod ast;
 
@@ -17,6 +18,7 @@ fn main() -> eframe::Result {
 struct CompilerApp {
     source_code: String,
     output_log: String,
+    env: Environment,
 }
 
 impl Default for CompilerApp {
@@ -24,6 +26,7 @@ impl Default for CompilerApp {
         Self {
             source_code: String::new(),
             output_log: String::from("Ready to compile..."),
+            env: Environment::new(),
         }
     }
 }
@@ -40,35 +43,16 @@ impl eframe::App for CompilerApp {
 
                 // Compile Button (at the top of the bottom panel)
                 if ui.button("Compile").clicked() {
-                    use crate::ast::parser::Parser;
-                    use crate::ast::nodes::Context;
-
-                    let mut parser = match Parser::new(&self.source_code) {
-                        Ok(p) => p,
-                        Err(e) => {
-                            self.output_log = format!("Lexer Error: {}", e);
-                            return;
-                        }
-                    };
-
-                    match parser.parse_expression() {
-                        Ok(ast) => {
-                            let mut context = Context::new(); // Use new() which registers stdlib
-                            match ast.eval(&mut context) {
-                                Ok(result) => {
-                                    self.output_log = format!(
-                                        "AST Parsed & Evaluated Successfully.\nResult: {}\n\nFinished at {:?}",
-                                        result,
-                                        std::time::SystemTime::now(),
-                                    );
-                                }
-                                Err(e) => {
-                                    self.output_log = format!("Runtime Error: {}", e);
-                                }
-                            }
+                    match self.env.run_script(&self.source_code) {
+                        Ok(result) => {
+                            self.output_log = format!(
+                                "Execution Successful.\nResult: {}\n\nFinished at {:?}",
+                                result,
+                                std::time::SystemTime::now(),
+                            );
                         }
                         Err(e) => {
-                            self.output_log = format!("Parser Error: {}", e);
+                            self.output_log = format!("Error: {}", e);
                         }
                     }
                 }