List errors

ID:1558432
 
Apr 25 2014, 7:32 am
(See the best response by Multiverse7.)
Problem description:Okay after being out of all of BYOND for months, I have become rusty at DM. I wanted to create a turn based game like final fantasy and pokemon but not publish it. I haven't mastered lists yet. I looked through the forums for the solutions but failed to find them. Here I get either cannot read from list or cannot modify /mob/ally/magician.loc errors. You see I want to have a party of about 7 members where you put up and can switch 3 members with any of the remaining 4. I keep getting errors.

Here are the codes:

turf
    Grass
        icon='turf.dmi'
        Entered(mob/player/m)
            if(m in m.allies)
                if(prob(3) && m.partyleader==TRUE && ismob(m))
                    m.prevloc=m.loc // remember previous location if you were to choose run
                    if(prob(50))
                        for(var/mob/mo in m.myparty)
                            m.inbattle=1
                        if(m.allies.len>0)//makes sure there is someone in the party greater than the number written so it won't give an error
                            var/mob/x=m.allies[1]
                            x.loc=locate(12,6,1)
                            x.inbattle=1
                            var/mob/x1=x.myparty[1] //error here or...
                            x1.loc=locate(x.x, x.y+1, x.z)//...error here or...
                            var/mob/x2=x.myparty[2]
                            x2.loc=locate(x.x, x.y-1, x.z)


etc...

mob/
    var
        list
            allies[0]
            enemies[0]
            totallist[0]
            listabilities=list("Fire")
            myparty



mob/player
    Login()
        src.icon = 'player.dmi'
        src.loc=locate(2,3,1)
        src.step_size = 8
        src.myparty=list(/mob/ally/magician,/mob/ally/melee_character,/mob/ally/projectiler,/mob/ally/piercing,/mob/ally/paladin)//...error here or...
        for(var/mob/m in src.myparty)
            m.inaparty=src
        src.inaparty=src
        world << src.myparty[1]//...error here
        battleinput()
Apr 25 2014, 7:50 am
You have to initialize memory for a list by declaring it's size and datatype.

Both of the following are equally correct:
mob/var/list/myParty=list()



mob/var/myParty[]


As per your error. You are trying to read a loc, a variable associated with an atom/movable from a typepath. You'll have to refer to the actual mob of magician, instead of just it's type.
Apr 25 2014, 9:57 am
Here I changed these:

mob/player
    Login()
        src.icon = 'player.dmi'
        src.loc=locate(2,3,1)
        src.step_size = 8
        src.myparty.Add(new/mob/ally/magician,new/mob/ally/melee_character,new/mob/ally/projectiler,new/mob/ally/piercing,new/mob/ally/paladin)//changed
        for(var/mob/m in src.myparty)
            m.inaparty=src
        src.inaparty=src
        world << src.myparty[1]
        battleinput()


And these:

mob/
    var
        list
            allies[0]
            enemies[0]
            totallist[0]
            listabilities=list("Fire")
            myparty[0]//changed
    contents=newlist(/obj/potion)


Now it gives me the error saying list index out of bounds.
Apr 25 2014, 10:06 am
You're creating a list with an index of zero. Arrays in DM must have an index of one or higher to have any values set.

mob/var/myparty[]//Creates an empty list, equivalent to calling mob/var/list/myparty=list().


Or, if you're interested in a fixed size, you can initialize it with a preset index.

mob/var/myparty[1000]//Creates a list with an index of 1000.


Apr 25 2014, 10:14 am
The "list index out of bounds" error means you are trying to access a list item at an index that doesn't exist. This makes sense, because it appears you are initializing the myparty[] list with an index of 0. The problem is at this line:
world << src.myparty[1]

If you want to use a list with a dynamic index that changes at runtime, you will need to make sure that an index exists before you try to access it. So, you can use a conditional check to resolve the error:
if(length(src.myparty) >= 1)
    world << src.myparty[1]

Does that eliminate the error?
Apr 25 2014, 10:29 am
I now initialized my list with mob/var/list/myparty=list() and at login added 
src.myparty.Add(new/mob/ally/magician,new/mob/ally/melee_character,new/mob/ally/projectiler,new/mob/ally/piercing,new/mob/ally/paladin)
. It still gives me errors.
Apr 25 2014, 10:41 am
I think newlist() would be a much better choice in this case, so try it like this instead:
src.myparty += newlist(/mob/ally/magician, /mob/ally/melee_character, /mob/ally/projectiler, /mob/ally/piercing, /mob/ally/paladin)


Also, it could be that one or more of those paths are not valid, so make sure that they are all defined correctly.
Apr 25 2014, 10:56 am
newlist didn't work
Apr 25 2014, 11:00 am
In response to TheDarkChakra
TheDarkChakra wrote:
newlist didn't work

That's very strange. What kind of errors are you getting exactly?
Apr 25 2014, 11:17 am
In response to Multiverse7
Multiverse7 wrote:
TheDarkChakra wrote:
newlist didn't work

That's very strange. What kind of errors are you getting exactly?

Index list out of bounds. It points to this code: 
                            var/mob/x1=x.myparty[1]
Apr 25 2014, 11:32 am
Is x1 being initialized before or after you add the mobs to the list? That should obviously only be done after the list has something in it.

Optionally, you can separate the initialization from the value you are setting it to:
var/mob/x1// This can be anywhere.

// This will patch up the error,
// but this part really needs to happen after you add something to the list,
// otherwise nothing will happen:
if(length(src.myparty) >= 1)
    x1 = x.myparty[1]

I hope this makes sense.
Apr 25 2014, 12:57 pm
I have been testing things out. It is at login that the list gets added to myparty list. But it doesn't get added. I made a debug verb that asks for the length of the list and it shows the list is empty even with src.myparty+=newlist(path, path 2, etc...) I then did 
src.myparty+=list(/mob/ally/magician,/mob/ally/melee_character,/mob/ally/projectiler,/mob/ally/piercing,/mob/ally/paladin)
and it did say the list is full but when I test the game it gives me the error that the /mob/ally/magician.loc cannot be modified. For some reason I can't add new mobs to the list. Help?
Apr 25 2014, 1:35 pm
Best response
What you are doing there is adding a list of type paths, not actual mobs. What newlist() does is take the types you give it, create new objects of those types and return a list of them.

Obviously a type path cannot have a loc, because it's just a type path. It's not an actual object instance.

It's hard to think of a reason why newlist() wouldn't work in this case. When you used newlist(), did it generate any errors at compile time or runtime?

If all of those paths are valid, the only thing that would make sense is if the mobs were being garbage collected, but for that to happen the myparty list would have to be cleared somewhere, which doesn't seem to be the case.

Are you overriding the New() proc somewhere for /mob or /mob/ally?

As a test, just try to add one object to the list and see what happens:
src.myparty += new /mob
if(!length(src.myparty))
    world << "Nothing was added to the list!"
// Under any normal conditions, the object will be added successfully.


If you don't get the message then that at least narrows down the problem a bit.
Apr 25 2014, 1:50 pm
 
mob/ally
    icon='magician.dmi'
    melee_character
    magician
    projectiler
    piercing
    paladin
    New()
        battleinput()


I did make a verb with that code you wrote to add to the mob and nothing happened so something was added to the list.

EDIT: I added to spawn() under New() and it looks like the code works. Looks like now I will have to move on to other problems outside this thread.