feat: 搭建闭包捕获基础设施

crates/oxide_compiler/src/emitter/expr/assignment.rs

@@ -142,6 +142,20 @@ impl Compiler {
             } else {
                 let val_reg = self.emit_expression(&assign.right, ctx)?;
                 let name = id_ref.name.as_str();
+                // Check if target is an upvalue reference
+                if let Some(uv_idx) = ctx.current_upvalue_captures.iter().position(|u| u.name == name) {
+                    ctx.emit(opcode::encode(OpCode::STORE_UPVALUE, 0, val_reg, uv_idx as u8));
+                    return Ok(val_reg);
+                }
+                // Check if target is a captured cell
+                if ctx.scopes.symbols.lookup_is_captured(name) {
+                    let cell_idx = ctx.scopes.cell_registry.iter()
+                        .find(|(n, _)| n == name)
+                        .map(|(_, idx)| *idx)
+                        .unwrap_or(0);
+                    ctx.emit(opcode::encode(OpCode::CELL_SET, 0, val_reg, cell_idx));
+                    return Ok(val_reg);
+                }
                 let var_reg = ctx.lookup_or_global(name);
                 let is_const = ctx.lookup_const_flag(name);
                 let const_flag = if is_const { 1 } else { 0 };

crates/oxide_compiler/src/emitter/expr/literal.rs

@@ -56,7 +56,34 @@ impl Compiler {
     pub(in crate::emitter) fn emit_identifier_expression(
         &self, ident: &oxide_parser::IdentifierReference, ctx: &mut CompileCtx,
     ) -> Result<u8, String> {
-        let var_reg = ctx.lookup_or_builtin(ident.name.as_str())?;
+        let name = ident.name.as_str();
+
+        // Check if this is an upvalue reference (nested closure)
+        for (uv_idx, up) in ctx.current_upvalue_captures.iter().enumerate() {
+            if up.name == name {
+                let r = ctx.alloc_reg();
+                let idx = uv_idx as u8;
+                ctx.emit(opcode::encode(OpCode::LOAD_UPVALUE, r, idx, 0));
+                return Ok(r);
+            }
+        }
+
+        // Check if the owner's binding is captured (cell access)
+        if ctx.scopes.symbols.lookup_is_captured(name) {
+            let cell_idx = ctx.scopes.cell_registry.iter()
+                .find(|(n, _)| n == name)
+                .map(|(_, idx)| *idx)
+                .unwrap_or(0);
+            let r = ctx.alloc_reg();
+            if let Some((binding, _)) = ctx.scopes.symbols.lookup_any_binding(name) {
+                ctx.emit(opcode::encode(OpCode::CELL_GET, r, binding.reg, cell_idx));
+            } else {
+                ctx.emit(opcode::encode(OpCode::CELL_GET, r, 0, cell_idx));
+            }
+            return Ok(r);
+        }
+
+        let var_reg = ctx.lookup_or_builtin(name)?;
         let r = ctx.alloc_reg();
         ctx.emit(opcode::encode(OpCode::LOAD_VAR, r, var_reg, 0));
         Ok(r)