Error7Studios
commented
3 years ago Now imagine Resource class with 100+ different properties
If you need to emit a signal for 100+ property changes, you should probably just use a dictionary instead of 100+ setters funcs
Thing class
extends Node
class_name Thing
signal value_changed(_self, key, old_value, new_value)
const KEY := { # dict keys
foo = "foo",
bar = "bar",
}
var dict := { # used instead of variables
KEY.foo: 100,
KEY.bar: 25,
}
func _init() -> void:
assert(KEY.values() == dict.keys())
func fetch(key: String):
assert(dict.has(key), str("Invalid key: ", key))
return dict[key]
func change(key: String, new_value, assert_same_type := true) -> void:
assert(dict.has(key), str("Invalid key: ", key))
var old_value = dict[key]
if assert_same_type:
assert(typeof(old_value) == typeof(new_value))
var accepted := true
match key:
KEY.foo:
if new_value < 0 or new_value > 99:
accepted = false
_:
pass # no condition checks for other keys
if accepted and old_value != new_value:
dict[key] = new_value
emit_signal("value_changed", self, key, old_value, new_value)
# emit_changed() # if ResourceThing parent
func _on_thing_value_changed(thing: Thing, key: String, old_value, new_value) -> void:
assert(thing)
print("Thing ", key, ":", old_value, "->", new_value, ", ", thing)
# other code here
func _ready() -> void:
var thing: Thing = $Thing
thing.connect("value_changed", self, "_on_thing_value_changed")
thing.change(Thing.KEY.foo, 150) # ignored. fails condition check
thing.change(Thing.KEY.foo, 75)prints:
Thing foo:100->75, [Node:1199]
Calinou
iiiCpu
OeilDeLance
As things are right now, programmer is forced to write lots of unnecessary code for properties. Just adding a signal is a challenge itself.
Now imagine Resource class with 100+ different properties because of
Describe the feature / enhancement and how it helps to overcome the problem or limitation
Add support for properties to use default implementations without\with signal, so programmers would write only necessary code. Maybe also make it possible to call default property method from reimplemented code.
Totally default property
Property with default signal
Property with custom setter and default getter and signal
If this enhancement will not be used often, can it be worked around with a few lines of script?
As GDScript does not currently support any type of metaprogramming the only way is the brute force way.
Yet using _set and _get for mass checks or signals is possible, it doesn't really help in the case. Instead of making code simpler and shorter it makes it more complicated and forces developer to duplicate code. And also moves most checks from core to user code in runtime. So, definitely, not a workaround to use in real code.
It is also possible for simple scripts to be generated from other scripts. And it works like charm except it doesn't. The code does not become simpler to read and modify.