gilzoide
commented
2 years ago Hi there!
Right now, to trigger a setter from Lua, just call the setter method or set explicitly, like:
self:set_some_property(value)
-- or
self:set('property', value)By the way, in GDScript, to call a setter method of a property defined in the script itself, you also have to explicitly call the method. This avoids recursion when the setter method sets the property itself and gives fine control over when calling the setter method is really needed.
var some_property setget set_some_property
func set_some_property(value):
# this does not call set_property again recursively
some_property = value
func some_unrelated_method():
# in fact, anywhere in this script that sets this
# property like this will not call the setter method
some_property = 42
func _ready():
# ok, now calling setter method
set_some_property(42)Now that I'm thinking of it, though, setting properties on self that are defined in base classes will not set them properly, which is bad =/
-- this will set the position in the script instance table, not the Node2D object
some_node2d.position = Vector2(1)
-- calling `set_position` or `set` is still the way, right now
some_node2d.set_position(Vector2(1))A __newindex metamethod that tries to set the property first or check if the property exists for the object or class could work.
-- Version 1
-- Problem with this is that calling `set` would convert
-- `value` to a Variant, so big tables would be converted to
-- Dictionaries just to potentially be thrown away.
-- Also, right now functions and coroutines cannot be
-- transformed into Variants, although they could be, by
-- incapsulating them as Objects
function ScriptInstance:__newindex(key, value)
if not self:set(key, value) then
rawset(self, key, value)
end
end
-- Version 2
function ScriptInstance:__newindex(key, value)
-- `has_property` doesn't exist, but would potentially
-- search results from `Object.get_property_list` or
-- `ClassDB.class_get_property_list`.
-- Generating an Array and making a linear search every
-- time __newindex is called doesn't seem too good, but we
-- could cache the property names in the Script, which
-- `self` always maintains a reference to
if self:has_property(key) then
self:set(key, value)
else
rawset(self, key, value)
end
endI like version 2 better, with some caching of the property names either eagerly when loading the script or lazily when the first __newindex gets called.
bojjenclon
Me again! In GDScript if you have a setter on a property and change it via
self.propertythe setter will be used. This doesn't apply to Lua, so I'm wondering how to trigger the setter from within a class method?