From 7cba4fdf7429e4f8b747bf31f9c3c6954824f716 Mon Sep 17 00:00:00 2001
From: Scott Wadden <dsrw@me.com>
Date: Tue, 2 Feb 2021 22:15:37 -0400
Subject: [PATCH] Don't create a VM for objects with no code

---
 enupkg/bot.nim     | 17 ++++++++++++++---
 enupkg/builder.nim | 20 ++++++++++++++------
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/enupkg/bot.nim b/enupkg/bot.nim
index f8969dff..3f48c250 100644
--- a/enupkg/bot.nim
+++ b/enupkg/bot.nim
@@ -92,15 +92,26 @@ gdobj NimBot of KinematicBody:
     err e.msg
     trigger("script_error")
 
+  proc default_script: string = 
+    join_path(config.lib_dir, "enu", "default_bot.nim")
+
+  proc is_script_loadable(): bool =
+    if self.enu_script != "none" and file_exists(self.enu_script):
+      let
+        default_code = read_file(self.default_script).strip
+        current_code = read_file(self.enu_script).strip
+
+      result = current_code != "" and current_code != default_code
+
   proc load_script() =
     trace:
-      if self.enu_script == "none":
-        return
       self.callback = nil
 
       try:
         if self.engine.is_nil:
           self.engine = Engine()
+        if not self.is_script_loadable:
+          return
         if not self.paused and not self.engine.initialized:
           debug &"Loading {self.enu_script}"
 
@@ -138,7 +149,7 @@ gdobj NimBot of KinematicBody:
       inc max_bot_index
       self.name = "Bot_" & $self.script_index
       self.set_script()
-      copy_file join_path(config.lib_dir, "enu", "default_bot.nim"), self.enu_script
+      copy_file self.default_script, self.enu_script
 
   method ready*() =
     trace:
diff --git a/enupkg/builder.nim b/enupkg/builder.nim
index 72ffdf6f..69bbc39f 100644
--- a/enupkg/builder.nim
+++ b/enupkg/builder.nim
@@ -65,6 +65,9 @@ gdobj Builder of Spatial:
   proc set_script() =
     self.enu_script = join_path(config.script_dir, &"grid_{self.script_index}.nim")
 
+  proc default_script: string = 
+    join_path(config.lib_dir, "enu", "default_grid.nim")
+
   proc setup*(translation: Vector3) =
     self.translation = translation
     self.original_translation = translation
@@ -72,7 +75,15 @@ gdobj Builder of Spatial:
     inc max_grid_index
     self.name = "Builder_" & $self.script_index
     self.set_script()
-    copy_file join_path(config.lib_dir, "enu", "default_grid.nim"), self.enu_script
+    copy_file self.default_script, self.enu_script
+
+  proc is_script_loadable(): bool =
+    if self.enu_script != "none" and file_exists(self.enu_script):
+      let
+        default_code = read_file(self.default_script).strip
+        current_code = read_file(self.enu_script).strip
+
+      result = current_code != "" and current_code != default_code
 
   proc save_blocks*() =
     let data = if self.draw_mode == VoxelMode:
@@ -356,15 +367,12 @@ gdobj Builder of Spatial:
     self.load_script()
 
   proc load_script() =
-    if self.enu_script == "none":
-      # can't use empty string because it gets set as nil, which is no longer valid nim.
-      # can probably be fixed in godot-nim
-      return
-    debug &"Loading {self.enu_script}. Paused {self.paused}"
     self.callback = nil
     self.blocks_remaining_this_frame = 0
     try:
       if self.engine.is_nil: self.engine = Engine()
+      if not self.is_script_loadable:
+        return
       if not (self.paused or self.engine.initialized):
         with self.engine:
           load(self.enu_script, config.lib_dir)