add Collect node (#165)

allows constructing arrays

Reviewed-on: https://codeberg.org/StreamGraph/StreamGraph/pulls/165
Co-authored-by: Lera Elvoé <yagich@poto.cafe>
Co-committed-by: Lera Elvoé <yagich@poto.cafe>

classes/deck/nodes/general/collect.gd

@@ -0,0 +1,93 @@
+# (c) 2023-present Eroax
+# (c) 2023-present Yagich
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+extends DeckNode
+
+var input_count: int:
+	get:
+		if input_count == 0:
+			return get_input_ports().size()
+		else:
+			return input_count
+
+
+func _init() -> void:
+	name = "Collect into Array"
+	node_type = "collect"
+	description = "Provides infinite inputs and an output that is an array of all connected inputs."
+	props_to_serialize = [&"input_count"]
+
+	add_output_port(
+		DeckType.Types.ARRAY,
+		"Array",
+		"",
+		Port.UsageType.VALUE_REQUEST,
+	)
+	
+	add_input_port(
+		DeckType.Types.ANY,
+		"Element 1",
+		"",
+		Port.UsageType.VALUE_REQUEST,
+	)
+
+	incoming_connection_added.connect(_on_incoming_connection_added)
+	incoming_connection_removed.connect(_on_incoming_connection_removed)
+
+
+func _on_incoming_connection_added(port_idx: int) -> void:
+	if port_idx + 1 < get_input_ports().size():
+		return
+
+	add_input_port(
+		DeckType.Types.ANY,
+		"Element %s" % (get_input_ports().size() + 1),
+		"",
+		Port.UsageType.VALUE_REQUEST,
+	)
+
+
+func _on_incoming_connection_removed(port_idx: int) -> void:
+	var last_connected_port := 0
+	var incoming_connections := _belonging_to.connections.get_all_incoming_connections(_id)
+	if not incoming_connections.is_empty():
+		last_connected_port = incoming_connections.keys().reduce(Util.array_max, -INF)
+
+	#prints("l:", last_connected_port, "p:", port_idx)
+
+	if port_idx < last_connected_port:
+		return
+
+	if get_input_ports().size() <= 2:
+		return
+
+	var lasts_connected_port_global = get_input_ports()[last_connected_port].index
+	var d = range(get_all_ports().size() - 1, lasts_connected_port_global + 1, -1)
+	for i in d:
+		ports.remove_at(i)
+	ports_updated.emit()
+
+
+func _pre_port_load() -> void:
+	ports.remove_at(1)
+	for i in input_count:
+		add_input_port(
+			DeckType.Types.ANY,
+			"Element %s" % (i + 1),
+			"",
+			Port.UsageType.VALUE_REQUEST,
+		)
+	input_count = 0
+
+
+func _value_request(_on_port: int) -> Variant:
+	var connections := _belonging_to.connections.get_all_incoming_connections(_id)
+	if connections.size() == 0:
+		return []
+	
+	var arr := []
+	arr.resize(connections.keys().reduce(Util.array_max, -INF) + 1)
+	for input_port in connections:
+		arr[input_port] = await resolve_input_port_value_async(input_port)
+	
+	return arr

classes/util.gd

@@ -46,6 +46,11 @@ static func globalize_path(path: String) -> String:
 	return path.format({"$PWD": pwd})
 
 
+## Use as the callback in [method Array.reduce] to find the greatest element.
+static func array_max(accum, e):
+	return max(accum, e)
+
+
 ## An object representing multiple connections.
 ##
 ## Useful when there's a need to connect multiple signals in one operation, to be disconnected later.