Add chrono dependency and example files

This commit introduces the `chrono` dependency to the project, enabling
the use of time-related functionalities. Additionally, it adds several
example files (`closure.myc`, `fib.myc`, `hof.myc`) to showcase the
language's features like closures, recursion, and higher-order
functions.

The `Cargo.lock` and `Cargo.toml` files have been updated to reflect the
new dependency. The `integration_test.rs` file now includes a test to
run all `.myc` files found in the `examples` directory, ensuring their
correctness. The `main.rs` file has also been updated to load and
display these examples in the UI.

src/main.rs

@@ -13,15 +13,37 @@ fn main() -> eframe::Result {
     )
 }
 
+struct Example {
+    name: String,
+    content: String,
+    is_benchmark: bool,
+}
+
 struct CompilerApp {
     source_code: String,
     output_log: String,
     env: Environment,
     is_first_frame: bool,
+    examples: Vec<Example>,
 }
 
 impl Default for CompilerApp {
     fn default() -> Self {
+        let examples = std::fs::read_dir("examples")
+            .map(|entries| {
+                entries
+                    .filter_map(|e| e.ok())
+                    .filter(|e| e.path().extension().map_or(false, |ext| ext == "myc"))
+                    .filter_map(|e| {
+                        let name = e.file_name().into_string().ok()?;
+                        let content = std::fs::read_to_string(e.path()).ok()?;
+                        let is_benchmark = content.contains(";; Benchmark");
+                        Some(Example { name, content, is_benchmark })
+                    })
+                    .collect()
+            })
+            .unwrap_or_default();
+
         Self {
             source_code: String::from(r#"
 (do
@@ -30,33 +52,29 @@ impl Default for CompilerApp {
       n
       (+ (fib (- n 1)) (fib (- n 2))))))
 
-  (def result (fib 10))
-  
-  (def data {
-    :name "Fibonacci"
-    :input 10
-    :output result
-    :sequence [0 1 1 2 3 5 8 13 21 34 55]
-  })
-  
-  data
+  (fib 10)
 )
 "#),
             output_log: String::from("Ready to compile..."),
             env: Environment::new(),
             is_first_frame: true,
+            examples,
         }
     }
 }
 
 impl CompilerApp {
     fn compile(&mut self) {
+        let start = std::time::Instant::now();
         match self.env.run_script(&self.source_code) {
             Ok(result) => {
+                let duration = start.elapsed();
+                let now = chrono::Local::now().format("%H:%M:%S").to_string();
                 self.output_log = format!(
-                    "Execution Successful.\nResult: {}\n\nFinished at {:?}",
+                    "Execution Successful.\nResult: {}\n\nDuration: {:?}\nFinished at: {}",
                     result,
-                    std::time::SystemTime::now(),
+                    duration,
+                    now,
                 );
             }
             Err(e) => {
@@ -68,6 +86,25 @@ impl CompilerApp {
 
 impl eframe::App for CompilerApp {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        // Left Side Panel: Examples
+        egui::SidePanel::left("examples_panel")
+            .resizable(true)
+            .default_width(150.0)
+            .show(ctx, |ui| {
+                ui.heading("Examples");
+                ui.add_space(5.0);
+                for example in &self.examples {
+                    let label = if example.is_benchmark {
+                        format!("⚡ {}", example.name)
+                    } else {
+                        example.name.clone()
+                    };
+                    if ui.button(label).clicked() {
+                        self.source_code = example.content.clone();
+                    }
+                }
+            });
+
         // Bottom Panel: Output Log & Controls (Resizable)
         egui::TopBottomPanel::bottom("bottom_panel")
             .resizable(true)
@@ -137,33 +174,3 @@ impl eframe::App for CompilerApp {
         });
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::ast::types::Value;
-
-    #[test]
-    fn test_basic_eval() {
-        let env = Environment::new();
-        let result = env.run_script("(+ 1 2)").unwrap();
-        if let Value::Int(i) = result {
-            assert_eq!(i, 3);
-        } else if let Value::Float(f) = result {
-            assert_eq!(f, 3.0);
-        } else {
-            panic!("Expected number result");
-        }
-    }
-
-    #[test]
-    fn test_type_error() {
-        let env = Environment::new();
-        // This should fail because 'if' condition must be bool (and currently '+' returns Any/Float/Int)
-        // Wait, '+' returns Any currently in my registration.
-        // Let's try something that definitely fails type check.
-        let result = env.run_script("(if 1 2 3)");
-        assert!(result.is_err());
-        assert!(result.unwrap_err().contains("Condition must be boolean"));
-    }
-}