Decouple block type from block variant

And use Variant.Type enum for the Value block variant.

This means we stick to GDScript variants for the values represented by
Value blocks:
- A constant like "viewport width"
- A property like "rotation"
- A parameter like A in "A + B"
- The resulting value of "A + B"

The slots that can contain Value blocks also have a matching variant
type now.

Unfortunately there is no way to convert the native Variant.Type enum to
string, so still we need dictionaries to go back and forth the string
formatting.

Previously there was a custom NODE type, although unused. This is now
replaced by NODE_PATH, which is the same thing that Godot does in the
PackedScene resource when exporting a property of type Node.

Also: improve readability of drag manager and use a constant for the
minimum slot distance.

addons/block_code/drag_manager/drag_manager.gd

@@ -8,6 +8,8 @@ signal block_modified
 @export var picker_path: NodePath
 @export var block_canvas_path: NodePath
 
+const Constants = preload("res://addons/block_code/ui/constants.gd")
+
 var drag_offset: Vector2
 var dragging: Block = null
 
@@ -39,38 +41,41 @@ func _process(_delta):
 		var closest_snap_point: SnapPoint = null
 		var closest_dist: float = INF
 		var snap_points: Array[Node] = get_tree().get_nodes_in_group("snap_point")
-		for n in snap_points:
-			if n is SnapPoint:
-				var snap_point: SnapPoint = n as SnapPoint
-				if snap_point.block == null:
-					push_error("Warning: a snap point does not reference it's parent block.")
-					continue
-				if snap_point.block.on_canvas:
-					if Types.can_cast(dragging.block_type, snap_point.block_type):
-						var snap_global_pos: Vector2 = snap_point.get_global_rect().position
-						var temp_dist: float = dragging_global_pos.distance_to(snap_global_pos)
-						if temp_dist < closest_dist:
-							# Check if any parent node is this node
-							var is_child: bool = false
-							var parent = snap_point
-							while parent is SnapPoint:
-								if parent.block == dragging:
-									is_child = true
-
-								parent = parent.block.get_parent()
-
-							if not is_child:
-								closest_dist = temp_dist
-								closest_snap_point = snap_point
-
-		if closest_dist > 80.0:
-			closest_snap_point = null
+		for snap_point in snap_points:
+			if not snap_point is SnapPoint:
+				push_error('Warning: a node in group "snap_point"snap is not of class SnapPoint.')
+				continue
+			if snap_point.block == null:
+				push_error("Warning: a snap point does not reference it's parent block.")
+				continue
+			if not snap_point.block.on_canvas:
+				# We only snap to blocks on the canvas:
+				continue
+			if dragging.block_type != snap_point.block_type:
+				# We only snap to the same block type:
+				continue
+			if dragging.block_type == Types.BlockType.VALUE and not Types.can_cast(dragging.variant_type, snap_point.variant_type):
+				# We only snap Value blocks to snaps that can cast to same variant:
+				continue
+			var snap_global_pos: Vector2 = snap_point.get_global_rect().position
+			var temp_dist: float = dragging_global_pos.distance_to(snap_global_pos)
+			if temp_dist <= Constants.MINIMUM_SNAP_DISTANCE and temp_dist < closest_dist:
+				# Check if any parent node is this node
+				var is_child: bool = false
+				var parent = snap_point
+				while parent is SnapPoint:
+					if parent.block == dragging:
+						is_child = true
+
+					parent = parent.block.get_parent()
+
+				if not is_child:
+					closest_dist = temp_dist
+					closest_snap_point = snap_point
 
 		if closest_snap_point != previewing_snap_point:
 			_update_preview(closest_snap_point)
 
-		# TODO: make sure dragging.block_type is the same as snap_point type
-
 
 func _update_preview(snap_point: SnapPoint):
 	previewing_snap_point = snap_point

addons/block_code/types/types.gd

@@ -3,34 +3,49 @@ extends Node
 
 enum BlockType {
 	NONE,
-	EXECUTE,
 	ENTRY,
-	# Parameters
-	STRING,
-	INT,
-	FLOAT,
-	VECTOR2,
-	BOOL,
-	COLOR,
-	NODE
+	EXECUTE,
+	VALUE,
+}
+
+const VARIANT_TYPE_TO_STRING: Dictionary = {
+	TYPE_STRING: "STRING",
+	TYPE_INT: "INT",
+	TYPE_FLOAT: "FLOAT",
+	TYPE_BOOL: "BOOL",
+	TYPE_VECTOR2: "VECTOR2",
+	TYPE_COLOR: "COLOR",
+	TYPE_NODE_PATH: "NODE_PATH",
+	TYPE_NIL: "NIL",
+}
+
+const STRING_TO_VARIANT_TYPE: Dictionary = {
+	"STRING": TYPE_STRING,
+	"INT": TYPE_INT,
+	"FLOAT": TYPE_FLOAT,
+	"BOOL": TYPE_BOOL,
+	"VECTOR2": TYPE_VECTOR2,
+	"COLOR": TYPE_COLOR,
+	"NODE_PATH": TYPE_NODE_PATH,
+	"NIL": TYPE_NIL,
 }
 
 const cast_relationships = [
-	[BlockType.INT, BlockType.FLOAT, "float(%s)"],
-	[BlockType.FLOAT, BlockType.INT, "int(%s)"],
-	[BlockType.INT, BlockType.STRING, "str(%s)"],
-	[BlockType.FLOAT, BlockType.STRING, "str(%s)"],
+	[TYPE_INT, TYPE_FLOAT, "float(%s)"],
+	[TYPE_FLOAT, TYPE_INT, "int(%s)"],
+	[TYPE_INT, TYPE_STRING, "str(%s)"],
+	[TYPE_FLOAT, TYPE_STRING, "str(%s)"],
 ]
 
 # Directed graph, edges are CastGraphEdge
 static var cast_graph: Dictionary
 
 
 class CastGraphEdge:
-	var to: BlockType
+	var to: Variant.Type
 	var cast_format: String
 
-	func _init(p_to: BlockType, p_cast_format: String):
+	func _init(p_to: Variant.Type, p_cast_format: String):
 		to = p_to
 		cast_format = p_cast_format
 
@@ -56,7 +71,7 @@ static var dist: Dictionary
 const INT_MAX: int = 1000000000
 
 
-static func dijkstra(source: BlockType):
+static func dijkstra(source: Variant.Type):
 	prev = {}
 	dist = {}
 
@@ -86,7 +101,7 @@ static func dijkstra(source: BlockType):
 				queue.update_priority(v, alt)
 
 
-static func can_cast(type: BlockType, parent_type: BlockType) -> bool:
+static func can_cast(type: Variant.Type, parent_type: Variant.Type) -> bool:
 	if type == parent_type:
 		return true
 
@@ -96,7 +111,7 @@ static func can_cast(type: BlockType, parent_type: BlockType) -> bool:
 	return false
 
 
-static func cast(val: String, type: BlockType, parent_type: BlockType):
+static func cast(val: String, type: Variant.Type, parent_type: Variant.Type):
 	if type == parent_type:
 		return val
 

addons/block_code/ui/blocks/entry_block/entry_block.gd

@@ -4,6 +4,7 @@ extends StatementBlock
 
 
 func _ready():
+	block_type = Types.BlockType.ENTRY
 	super()
 
 

addons/block_code/ui/blocks/entry_block/entry_block.tscn

@@ -7,4 +7,7 @@
 script = ExtResource("2_3ik8h")
 block_name = "entry_block"
 label = "EntryBlock"
-block_type = 2
+block_type = 1
+
+[node name="Background" parent="VBoxContainer/TopMarginContainer" index="0"]
+show_top = false

addons/block_code/ui/blocks/parameter_block/parameter_block.gd

@@ -4,6 +4,7 @@ extends Block
 
 @export var block_format: String = ""
 @export var statement: String = ""
+@export var variant_type: Variant.Type
 
 @onready var _panel := $Panel
 @onready var _hbox := %HBoxContainer
@@ -15,6 +16,7 @@ var param_input_strings: Dictionary  # Only loaded from serialized
 func _ready():
 	super()
 
+	block_type = Types.BlockType.VALUE
 	var new_panel = _panel.get_theme_stylebox("panel").duplicate()
 	new_panel.bg_color = color
 	new_panel.border_color = color.darkened(0.2)

addons/block_code/ui/blocks/statement_block/statement_block.gd

@@ -100,12 +100,12 @@ static func format_string(parent_block: Block, attach_to: Node, string: String)
 		var split := param.split(": ")
 		var param_name := split[0]
 		var param_type_str := split[1]
-		var param_type := Types.BlockType.get(param_type_str)
+		var param_type: Variant.Type = Types.STRING_TO_VARIANT_TYPE[param_type_str]
 
 		var param_input: ParameterInput = preload("res://addons/block_code/ui/blocks/utilities/parameter_input/parameter_input.tscn").instantiate()
 		param_input.name = "ParameterInput%d" % start  # Unique path
 		param_input.placeholder = param_name
-		param_input.block_type = param_type
+		param_input.variant_type = param_type
 		param_input.block = parent_block
 		param_input.text_modified.connect(func(): parent_block.modified.emit())
 		attach_to.add_child(param_input)
@@ -115,7 +115,7 @@ static func format_string(parent_block: Block, attach_to: Node, string: String)
 			var new_block: Block = preload("res://addons/block_code/ui/blocks/parameter_block/parameter_block.tscn").instantiate()
 			new_block.block_format = param_name
 			new_block.statement = param_name
-			new_block.block_type = param_type
+			new_block.variant_type = param_type
 			new_block.color = parent_block.color
 			param_input.block_type = Types.BlockType.NONE
 			param_input.snap_point.block_type = Types.BlockType.NONE  # Necessary because already called ready

addons/block_code/ui/blocks/utilities/parameter_input/parameter_input.gd

@@ -9,7 +9,8 @@ signal text_modified
 
 @export var block_path: NodePath
 
-@export var block_type: Types.BlockType = Types.BlockType.STRING
+@export var variant_type: Variant.Type = TYPE_STRING
+@export var block_type: Types.BlockType = Types.BlockType.VALUE
 
 var block: Block
 
@@ -41,6 +42,7 @@ func _ready():
 		block = get_node_or_null(block_path)
 	snap_point.block = block
 	snap_point.block_type = block_type
+	snap_point.variant_type = variant_type
 
 	# Do something with block_type to restrict input
 
@@ -50,16 +52,16 @@ func get_snapped_block() -> Block:
 
 
 func get_string() -> String:
-	var snapped_block: Block = get_snapped_block()
+	var snapped_block: ParameterBlock = get_snapped_block() as ParameterBlock
 	if snapped_block:
 		var generated_string = snapped_block.get_parameter_string()
-		return Types.cast(generated_string, snapped_block.block_type, block_type)
+		return Types.cast(generated_string, snapped_block.variant_type, variant_type)
 
 	var text: String = get_plain_text()
 
-	if block_type == Types.BlockType.STRING:
+	if variant_type == TYPE_STRING:
 		text = "'%s'" % text.replace("\\", "\\\\").replace("'", "\\'")
-	if block_type == Types.BlockType.VECTOR2:
+	elif variant_type == TYPE_VECTOR2:
 		text = "Vector2(%s)" % text
 
 	return text

addons/block_code/ui/blocks/utilities/snap_point/snap_point.gd

@@ -6,6 +6,9 @@ extends MarginContainer
 
 @export var block_type: Types.BlockType = Types.BlockType.EXECUTE
 
+## Only used when block_type is a [enum Types.BlockType.VALUE].
+@export var variant_type: Variant.Type
+
 var block: Block
 
 

addons/block_code/ui/constants.gd

@@ -6,3 +6,4 @@ const KNOB_H = 5.0
 const KNOB_Z = 5.0
 const CONTROL_MARGIN = 20.0
 const OUTLINE_WIDTH = 3.0
+const MINIMUM_SNAP_DISTANCE = 80.0