There are questions about how this filter should treat empty values, and the
use cases that we can think of can be implemented in other ways, for example,
if we want to look for big damage boosts, then we could filter for
`add=5-infinity` `[or]` `multiply=2-infinity`.
The simple answer seems to be to remove it from the API before we freeze for 1.18.
There's more discussion in issue 7944.
using overwrite_specials alone means that we have only two possibilities, either one_side is chosen and in this case if the ability used as a weapon carrying the attribute is applied to the unit (apply_to=self), the other abilities are the same type applied also to 'self' not carrying the attribute will be overwritten, but those of the opponent with apply_to=opponent will be kept in the list; or else both_sides is chosen and all abilities of the same type that do not carry the attribute will be overwritten. To be able to use the attribute in abilities like [damage] for example, it is necessary to be able to be even more selective as for a 'charge' type leadership with multiply=2.5 but which must not be combined with the classic charge and without overwriting the aute [damage] as backstab, [overwrite_filter] to only match damage with apply_to=both and active_on=offense is then interesting.
adding priority allows you to select that it ability can use its overwrite_specials attribute while the others can be overwritten in the same way as an ability without the attribute. Finally, this system makes it unnecessary to limit the use of the attribute to abilities used as weapons but also to special weapons.
give abilities support of halo or overlay so that the unit benefits from a second halo or overlay when conditions are matched
One of the things that bothers me is the permanent character of the halos of the Mage of Light and other units with the "illuminates" ability, which forces them to program only a permanent illumination applied only to the possessor of the ability.
Adding the halo attribute to ability does not change anything about the behavior of the unit, but can be used in several cases:
1 allowing the use of ""illuminates" whose activity would be variable, in this case encoding the halo in [illuminates] ability and not in the unit_type allows to modulate the appearance of the halo under the same conditions
2. Applying illumination to adjacent units, I know it's pretty cheesy but a set developer might consider it easier if the hlo display follows the same logic.
3 The halo used to illustrate the possession in the unit of a special weapon used as leadership, the halo would be used to raise the possessor of the ability.
for overlay, same logic for illustrate possession of a special weapon used as leadership, or influence on student
with the "halo_image" attribute, it is now possible to give Sun Sylph units an illumination ability with an activity depending on the incarnate sun attack instead of giving the ability and the halo via obect and therefore allowing the player to have access to the description of the ability even when it is inactive.
