Move DragManager.get_tree_scope to InstructionTree

This static function has nothing to do with the DragManager class since
it's simply walking a tree of Nodes and looking for a Block that has a
non-empty scope property set. I'm not sure it really fits in
InstructionTree either, but that's a better fit at least. This avoids
some dependency issues between DragManager, its inner Drag class, and
BlockCanvas.

https://phabricator.endlessm.com/T35494

Author: dbnicholson

addons/block_code/drag_manager/drag.gd

@@ -3,7 +3,7 @@ extends Control
 
 const BlockCanvas = preload("res://addons/block_code/ui/block_canvas/block_canvas.gd")
 const Constants = preload("res://addons/block_code/ui/constants.gd")
-const DragManager = preload("res://addons/block_code/drag_manager/drag_manager.gd")
+const InstructionTree = preload("res://addons/block_code/instruction_tree/instruction_tree.gd")
 const Types = preload("res://addons/block_code/types/types.gd")
 
 enum DragAction { NONE, PLACE, REMOVE }
@@ -142,7 +142,7 @@ func _snaps_to(node: Node) -> bool:
 			if _block_scope != top_block.get_entry_statement():
 				return false
 		elif top_block:
-			var tree_scope := DragManager.get_tree_scope(top_block)
+			var tree_scope := InstructionTree.get_tree_scope(top_block)
 			if tree_scope != "" and _block_scope != tree_scope:
 				return false
 

addons/block_code/drag_manager/drag_manager.gd

@@ -6,6 +6,7 @@ signal block_modified
 
 const BlockCanvas = preload("res://addons/block_code/ui/block_canvas/block_canvas.gd")
 const Drag = preload("res://addons/block_code/drag_manager/drag.gd")
+const InstructionTree = preload("res://addons/block_code/instruction_tree/instruction_tree.gd")
 const Picker = preload("res://addons/block_code/ui/picker/picker.gd")
 
 @export var picker_path: NodePath
@@ -49,7 +50,7 @@ func drag_block(block: Block, copied_from: Block = null):
 
 	block.disconnect_signals()
 
-	var block_scope := get_tree_scope(block)
+	var block_scope := InstructionTree.get_tree_scope(block)
 	if block_scope != "":
 		_block_canvas.set_scope(block_scope)
 
@@ -92,16 +93,3 @@ func connect_block_canvas_signals(block: Block):
 		block.drag_started.connect(drag_block)
 	if block.modified.get_connections().size() == 0:
 		block.modified.connect(func(): block_modified.emit())
-
-
-## Returns the scope of the first non-empty scope child block
-static func get_tree_scope(node: Node) -> String:
-	if node is Block:
-		if node.scope != "":
-			return node.scope
-
-	for c in node.get_children():
-		var scope := get_tree_scope(c)
-		if scope != "":
-			return scope
-	return ""

addons/block_code/instruction_tree/instruction_tree.gd

@@ -120,3 +120,16 @@ static func _generate_script_from_entry_blocks(entry_statement: String, entry_bl
 		script += "\tpass\n\n"
 
 	return script
+
+
+## Returns the scope of the first non-empty scope child block
+static func get_tree_scope(node: Node) -> String:
+	if node is Block:
+		if node.scope != "":
+			return node.scope
+
+	for c in node.get_children():
+		var scope := get_tree_scope(c)
+		if scope != "":
+			return scope
+	return ""

addons/block_code/ui/block_canvas/block_canvas.gd

@@ -218,7 +218,7 @@ func set_scope(scope: String):
 			if scope == block.get_entry_statement():
 				valid = true
 		else:
-			var tree_scope := DragManager.get_tree_scope(block)
+			var tree_scope := InstructionTree.get_tree_scope(block)
 			if tree_scope == "" or scope == tree_scope:
 				valid = true