Output to Grid

ID:1416798
 
Nov 8 2013, 2:22 pm
(See the best response by DarkCampainger.)
Hey guys. I'm having a strange issue when trying to output to a grid.

I am using the grid to show the user his/her available spells, which can then be cast by clicking. Here is the code that updates the list of spells:

UpdateSpells()
            var/count=1
            var/tmp/list/allspells=new()
            usr.spells=null
            allspells+=new/obj/magic/windbreeze
            allspells+=new/obj/magic/windgust
            allspells+=new/obj/magic/windblast
            allspells+=new/obj/magic/windstorm
            allspells+=new/obj/magic/tornado
            allspells+=new/obj/magic/cook1
            allspells+=new/obj/magic/lightlogs
            allspells+=new/obj/magic/fireball
            allspells+=new/obj/magic/cook2
            allspells+=new/obj/magic/fireblast
            allspells+=new/obj/magic/cook3
            allspells+=new/obj/magic/firestorm
            allspells+=new/obj/magic/breathefire
            allspells+=new/obj/magic/waterball
            allspells+=new/obj/magic/telekaishi
            allspells+=new/obj/magic/telekminor
            allspells+=new/obj/magic/heal1
            allspells+=new/obj/magic/waterblast
            allspells+=new/obj/magic/telesd
            allspells+=new/obj/magic/heal2
            allspells+=new/obj/magic/telekmajor
            allspells+=new/obj/magic/waterstorm
            allspells+=new/obj/magic/heal3
            allspells+=new/obj/magic/whirlpool
            allspells+=new/obj/magic/alchemize1
            allspells+=new/obj/magic/deposititem
            allspells+=new/obj/magic/alchemize2
            allspells+=new/obj/magic/withdrawitem
            allspells+=new/obj/magic/alchemize3
            for(var/obj/magic/O in allspells)
                if(O.levelreq<=usr.magic)
                    usr<<output(O,"spellswindow.spellsgrid:[count++]")


and here is a picture of what happens:



The strange thing is that everything works perfectly and all of the spells show up properly, but after a few seconds, a few of them change to objs. Each time this happens, it's different spells that transform. Really stumped on this.
Nov 8 2013, 3:05 pm
Where are those icons being pulled from (the yellow numbers)? It might give some indication where the problem is coming from, seems to me like there's something else in your code conflicting with this.
Nov 8 2013, 3:12 pm
I have those numbers in a few places, but only on the interface. They are used for showing level and gold on client.screen.
Nov 8 2013, 5:18 pm
Best response
You're outputting temporary objects to your grid. Being displayed in a grid does not count as a reference, so they get garbage collected and their appearance is recycled.

Skin reference:
Very important: If you send an atom to a grid like you would with a statpanel, keep that object in a list or make sure it actually exists somewhere in the world. Do not use a temporary object that will be deleted when the proc ends, or it can disappear/change in the grid when a new object is created.

Did you intend to set usr.spells to allspells to hold on to them?
Nov 8 2013, 6:06 pm
Ah, good catch. I didn't notice allspells was a local variable, that would indeed be the problem.
Nov 9 2013, 1:53 am
Good call on that one! I'm not sure what the issues is now, though...when I use a non-temporary list, I get a runtime error:

UpdateSpells()
            var/count=0
            usr.spells=null
            usr.spells+=new/obj/magic/windbreeze
            usr.spells+=new/obj/magic/windgust
            usr.spells+=new/obj/magic/windblast
            usr.spells+=new/obj/magic/windstorm
            usr.spells+=new/obj/magic/tornado
            usr.spells+=new/obj/magic/cook1
            usr.spells+=new/obj/magic/lightlogs
            usr.spells+=new/obj/magic/fireball
            usr.spells+=new/obj/magic/cook2
            usr.spells+=new/obj/magic/fireblast
            usr.spells+=new/obj/magic/cook3
            usr.spells+=new/obj/magic/firestorm
            usr.spells+=new/obj/magic/breathefire
            usr.spells+=new/obj/magic/waterball
            usr.spells+=new/obj/magic/telekaishi
            usr.spells+=new/obj/magic/telekminor
            usr.spells+=new/obj/magic/heal1
            usr.spells+=new/obj/magic/waterblast
            usr.spells+=new/obj/magic/telesd
            usr.spells+=new/obj/magic/heal2
            usr.spells+=new/obj/magic/telekmajor
            usr.spells+=new/obj/magic/waterstorm
            usr.spells+=new/obj/magic/heal3
            usr.spells+=new/obj/magic/whirlpool
            usr.spells+=new/obj/magic/alchemize1
            usr.spells+=new/obj/magic/deposititem
            usr.spells+=new/obj/magic/alchemize2
            usr.spells+=new/obj/magic/withdrawitem
            usr.spells+=new/obj/magic/alchemize3
            for(var/obj/magic/O in usr.spells)
                if(O.levelreq<=usr.magic)
                    usr<<output(O,"spellswindow.spellsgrid:[count++]")


runtime error: type mismatch: Wind Breeze (Level 1) (/obj/magic/windbreeze) += Wind Gust (Level 12) (/obj/magic/windgust)
proc name: UpdateSpells (/mob/proc/UpdateSpells)
usr: TEST (/mob/player)
src: TEST (/mob/player)
call stack:
TEST (/mob/player): UpdateSpells()
TEST (/mob/player): Spells()

It looks to me like it's trying to add the next obj where it should be adding the previous. Any insights?
Nov 9 2013, 6:30 am
You didn't create the list: usr.spells=new/list()

null + windbreeze = windbreeze
windbreeze + windgust = undefined operator/type mismatch.
Nov 9 2013, 7:41 am
I have the list created elsewhere because it serves other purposes in other places in the code. :/
Nov 9 2013, 7:48 am
What DarkCampainger is referring to is the line usr.spells=null.
Nov 9 2013, 7:51 am
Yeah, I see it now. Thanks for the help, guys. It's working perfectly now!!