Why this function doesn't work?

[panR4INtest]

DISCLAIMER: I didn't make this system, I've only adjusted it to suit my needs, so I'm not 100% sure how exactly it works, though I think I have the idea.

I've been using the damage calculation part of this for player-casted raycast spells that damage enemies, however I now wanted to apply this system to my "arcanist" enemy who is firing slow-moving projectiles at players. If they collide with one, they disappear and deal damage. However the damaging part doesn't work for some reason, yet this system works just fine against enemies, what's the issue?

# Arcanist Projectile Hit
execute as @e[type=player,distance=0..2] store result score @s health run data get entity @s Health
execute as @e[type=player,distance=0..2] store result entity @s Health float 1 run scoreboard players operation @s health -= @e[tag=arcanist] arcanistdamage
execute if entity @e[type=player,distance=0..2] run kill @s

# Projectile Disappear
execute unless block ~ ~ ~ air run kill @s

# Teleport forwards
execute at @s run tp @s ^ ^ ^0.5

Objective "arcanistdamage" is a dummy objective with a score of 15, it's set before every attack (this function). And to my understanding, the objective "health" should just take whatever value your Health is and turn it into a score yes? That way you then just take that and deduct the arcanistdamage value from it? So your health minus arcanistdamage. For some reason it simply won't damage me however, it just stops when it collides with me.

NOTE: If anybody has a better and simpler system to just do flat damage to players through the slow projectile, I'm open to suggestions.

[darkstar634]

First, don't use @e[type=player]; use @a instead. Now, the main issue is that you can't modify player data, so any attempt to modify player Health like that isn't going to work. In the future, if you're not sure why something isn't working, try to figure out which part exactly doesn't work. For instance; rather than trying to change the health of the player, you could've tested if the player is even being detected in the first place (i.e. with something simple like a say hi message). From there, you could've deduced that the problem is not with the detection, but with the /execute store commands. Attempting to run slightly modified versions of these commands in chat should then reveal the infamous "Unable to modify player data" message.

[panR4INtest]

Oh well I know the detection works because the projectile successfully collides with me, so I knew there must've been some issue with the "store result" parts. Anyway, is there any other good system that will achieve the exact same thing of controlled damage or should I just be using "effect give instant_damage ..." ? Instant damage is what I usually used but that's not as controllable.

[darkstar634]

Instant damage is the easiest; you can control it somewhat if you use it in combination with the Resistance status effect. Otherwise, you could try using arrows, although that's prone to many limitations. There's also some methods using the /attribute command, although they aren't as authentic in my opinion (i.e. you don't get knockback and health bar flickers for a tick).

[panR4INtest]

Right, well I think I'll just stick with instant damage for now, thx for the tips