add object list cleaning on VM.deinit

src/main.zig

@@ -17,6 +17,7 @@ fn run(allocator: *Allocator, data: []u8) !void {
     const stdout = &stdout_file.outStream().stream;
 
     var vmach = try vm.VM.init(allocator, stdout, data, true);
+    defer vmach.deinit();
     try vmach.interpret();
 }
 

src/vm.zig

@@ -74,6 +74,36 @@ pub const VM = struct {
         return self;
     }
 
+    fn deinitObject(self: *VM, obj: *objects.Object) void {
+        switch (obj.otype) {
+            .String => blk: {
+                self.allocator.free(obj.value.String);
+                self.allocator.destroy(obj);
+                break :blk;
+            },
+            else => unreachable,
+        }
+    }
+
+    fn deinitObjects(self: *VM) void {
+        var obj_opt: ?*objects.Object = self.objs;
+
+        // doing a while(obj != null) but with optionals
+        while (true) {
+            if (obj_opt) |obj| {
+                var next = obj.next;
+                self.deinitObject(obj);
+                obj_opt = next;
+            } else {
+                break;
+            }
+        }
+    }
+
+    pub fn deinit(self: *VM) void {
+        self.deinitObjects();
+    }
+
     pub fn debug(self: *VM, comptime fmt: []const u8, args: ...) void {
         if (self.debug_flag) {
             std.debug.warn(fmt, args);