Refactor environment loading and program execution

The `preload_dependencies` function has been refactored to directly run
parsed programs instead of collecting all forms into a single `Program`
node. This simplifies the compilation pipeline by allowing each
dependency to be processed individually.

Additionally, the `VM::run_with_observer` method has been updated to
manage its stack and frames more cleanly, avoiding the need for
`eval_in_frame`. The main loop now correctly extracts expressions from
the `Program` node for source code emission.

src/ast/environment.rs

@@ -5,7 +5,7 @@ use crate::ast::compiler::{CapturePass, TypeChecker, TypedNode};
 use crate::ast::nodes::{AnalyzedPhase, BoundPhase, Symbol, SyntaxKind, SyntaxNode};
 use crate::ast::parser::Parser;
 use crate::ast::closure::Closure;
-use crate::ast::vm::{self, GlobalStore, TracingObserver, VM};
+use crate::ast::vm::{GlobalStore, TracingObserver, VM};
 use std::cell::RefCell;
 use std::collections::{HashMap, HashSet};
 use std::path::{Path, PathBuf};
@@ -334,23 +334,20 @@ impl Environment {
     /// Used to pre-load all dependencies of a script before compiling it.
     pub fn preload_dependencies(&self, source: &str, file_path: Option<&Path>) -> Result<(), String> {
         let base_path = file_path.and_then(|p| p.parent()).unwrap_or_else(|| Path::new("."));
-        let mut all_forms: Vec<Rc<SyntaxNode>> = Vec::new();
 
         // 1. Always load the embedded system library first as a virtual module
         let system_path = PathBuf::from(SYSTEM_LIB_PATH);
         if !self.loaded_modules.borrow().contains(&system_path) {
             self.loaded_modules.borrow_mut().insert(system_path.clone());
             let mut parser = Parser::new(SYSTEM_LIB_SOURCE);
-            let forms = parser.parse_program();
+            let program = parser.parse_program();
             if parser.diagnostics.has_errors() {
                 return Err(format!(
                     "Failed to parse embedded system library:\n{}",
                     parser.diagnostics.items[0].message
                 ));
             }
-            for form in forms {
-                all_forms.push(Rc::new(form));
-            }
+            self.run_program(program)?;
         }
 
         // 2. Collect user dependencies (file I/O + parse, topological order)
@@ -358,43 +355,38 @@ impl Environment {
             Rc::clone(&self.search_paths),
             Rc::clone(&self.loaded_modules),
         );
-        for (_, syntax_ast) in loader.collect_dependency_files(source, base_path)? {
-            all_forms.push(Rc::new(syntax_ast));
+        for (path, syntax_ast) in loader.collect_dependency_files(source, base_path)? {
+            let compiled = self.compile_pipeline(syntax_ast, &mut Diagnostics::new())
+                .ok_or_else(|| format!("Compilation error in {}", path.display()))?;
+            self.run_script_compiled(compiled).map_err(|e| {
+                format!("Initialization error in {}:\n{}", path.display(), e)
+            })?;
         }
 
-        // Compile and initialize all forms as a single program (no scope boundary)
-        if !all_forms.is_empty() {
-            let block = SyntaxNode {
-                identity: NodeIdentity::anonymous(),
-                kind: SyntaxKind::Program { exprs: all_forms },
-                ty: (),
-                comments: Rc::from([]),
-            };
-            let mut diagnostics = Diagnostics::new();
+        Ok(())
+    }
 
-            // 1. Expand macros
-            let expanded = self.expand(block, &mut diagnostics)
-                .ok_or_else(|| diagnostics.format_errors())?;
+    /// Compiles and executes a `Program` node without lambda wrapping.
+    /// Definitions at the top level receive `Address::Global` and persist
+    /// in the GlobalStore for subsequent compilation units.
+    fn run_program(&self, program: SyntaxNode) -> Result<(), String> {
+        let mut diagnostics = Diagnostics::new();
 
-            // 2. Bind names and update root scopes
-            let bound = self.bind_and_update(&expanded, &mut diagnostics)
-                .ok_or_else(|| diagnostics.format_errors())?;
+        let expanded = self.expand(program, &mut diagnostics)
+            .ok_or_else(|| diagnostics.format_errors())?;
 
-            // 3. Type-check (without lambda wrapping)
-            let typed = self.type_check(&bound, &mut diagnostics);
+        let bound = self.bind_and_update(&expanded, &mut diagnostics)
+            .ok_or_else(|| diagnostics.format_errors())?;
 
-            if diagnostics.has_errors() {
-                return Err(diagnostics.format_errors());
-            }
+        let typed = self.type_check(&bound, &mut diagnostics);
 
-            // 4. Link and execute
-            let linked = self.link(typed);
-            let mut vm = self.create_vm();
-            let stack = vec![Value::Void; linked.ty.stack_size as usize];
-            let result = vm.eval_in_frame(&mut vm::NoOpObserver, &linked, stack)?;
-            vm.resolve_tail_calls(&mut vm::NoOpObserver, Ok(result))?;
+        if diagnostics.has_errors() {
+            return Err(diagnostics.format_errors());
         }
 
+        let linked = self.link(typed);
+        let mut vm = self.create_vm();
+        vm.run(&linked)?;
         Ok(())
     }
 

src/ast/parser.rs

@@ -119,13 +119,20 @@ impl<'a> Parser<'a> {
         matches!(self.current_token.kind, TokenKind::EOF)
     }
 
-    /// Parses a complete program as a sequence of top-level expressions.
-    pub fn parse_program(&mut self) -> Vec<SyntaxNode> {
+    /// Parses a complete program as a sequence of top-level expressions
+    /// wrapped in a `Program` node.
+    pub fn parse_program(&mut self) -> SyntaxNode {
+        let identity = NodeIdentity::new(SourceLocation { line: 1, col: 1 });
         let mut expressions = Vec::new();
         while !self.at_eof() {
-            expressions.push(self.parse_expression());
+            expressions.push(Rc::new(self.parse_expression()));
+        }
+        SyntaxNode {
+            identity,
+            kind: SyntaxKind::Program { exprs: expressions },
+            ty: (),
+            comments: Rc::from([]),
         }
-        expressions
     }
 
     fn synchronize(&mut self) {

src/ast/vm.rs

@@ -266,27 +266,23 @@ impl VM {
         self.resolve_tail_calls(observer, result)
     }
 
-    pub fn eval_in_frame<O: VMObserver>(&mut self, observer: &mut O, root: &ExecNode, stack: Vec<Value>) -> Result<Value, String> {
-        self.stack = stack;
-        self.frames.clear();
-        self.frames.push(CallFrame {
-            stack_base: 0,
-            closure: None,
-        });
-        let result = self.eval_internal(observer, root);
-        self.frames.pop();
-        result
-    }
 
     pub fn run_with_observer<O: VMObserver>(
         &mut self,
         observer: &mut O,
         root: &ExecNode,
     ) -> Result<Value, String> {
-        let mut stack = Vec::new();
-        stack.resize(root.ty.stack_size as usize, Value::Void);
+        self.stack.clear();
+        self.frames.clear();
 
-        let result = self.eval_in_frame(observer, root, stack);
+        self.stack.resize(root.ty.stack_size as usize, Value::Void);
+
+        self.frames.push(CallFrame {
+            stack_base: 0,
+            closure: None,
+        });
+        let result = self.eval_internal(observer, root);
+        self.frames.pop();
         self.resolve_tail_calls(observer, result)
     }
 

src/main.rs

@@ -2,6 +2,7 @@ use eframe::egui;
 use egui_extras::{Column, TableBuilder};
 use myc::ast::compiler::emitter;
 use myc::ast::environment::Environment;
+use myc::ast::nodes::SyntaxKind;
 use myc::ast::parser::Parser;
 use std::path::PathBuf;
 
@@ -198,7 +199,12 @@ impl CompilerApp {
             self.active_tab = AppTab::Output;
             return;
         }
-        self.source_code = expressions.iter().map(emitter::emit).collect::<Vec<_>>().join("\n");
+        let exprs = if let SyntaxKind::Program { exprs } = &expressions.kind {
+            exprs.as_slice()
+        } else {
+            &[]
+        };
+        self.source_code = exprs.iter().map(|e| emitter::emit(e)).collect::<Vec<_>>().join("\n");
         self.output_log = "Roundtrip complete — source reformatted.".to_string();
         self.active_tab = AppTab::Output;
     }