Strange Shopkeep Error

ID:1987657
 
Nov 23 2015, 11:52 am
(See the best response by Kozuma3.)
Code:
mob
    NPC

        shopkeeper
            planet=""
            icon = 'Shopkeeper.dmi'
            
            Vegeta
                icon_state="Vegeta"
                layer=50
                density=1
                attackable=0
            Namek
                icon_state="Namek"
                layer=50
                density=1
                attackable=0
            Earth
                icon_state="Earth"
                layer=50
                density=1
                attackable=0
            Icer
                icon_state="Icer"
                layer=50
                density=1
                attackable=0
            Hell
                icon_state="Hell"
                layer=50
                density=1
                attackable=0
            Heaven
                icon_state="Heaven"
                layer=50
                density=1
                attackable=0

            DblClick()
                Installshop()
                var/player/P = usr
                if(!P.frozen)
                    switch(input("Welcome to your local shopkeeper.") in list ("Buy","Sell","Cancel"))
                        if("Buy")
                            var/obj/Item/R = input("What would you like to buy?","Shopkeep",text)in contents
                            if(alert("Buy [R]? Cost: [R.cost] zenni","Yes","No")=="Yes")
                                if(R.cost>P.zenni)
                                    P.zenni -= R.cost   
                                    new R(usr)
                                    P<<"You bought [R]!"
                                else
                                    P<<"You do not have enough zenni!"
                        if("Sell")
                            var/list/sellable = list()
                            for(var/obj/O in usr)
                                if(istype(O))
                                    sellable += O
                                    break
                                var/selling = input(sellable)
                                if(alert("I'll give you [O.cost * O.buyprice] for it.  Deal?", "Yes", "No") == "Yes")
                                    usr << "Thank you for your business!"
                                    usr.zenni += O.cost * O.buyprice
                                    del(selling)


Problem description:

After the input opens asking to Buy or Sell, I click Buy and I get an in-game error:

runtime error: Cannot read null.cost
proc name: DblClick (/mob/NPC/shopkeeper/DblClick)
source file: Shopkeeper.dm,48
usr: Lol (/player)
src: Vegeta (/mob/NPC/shopkeeper/Vegeta)
usr.loc: Desert Five (114,135,4) (/turf/newturfs/Desert_Five)
src.loc: the cliff23 (114,136,4) (/turf/cliff2/cliff23)
call stack:
Vegeta (/mob/NPC/shopkeeper/Vegeta): DblClick(the cliff23 (114,136,4) (/turf/cliff2/cliff23), "default.map", "icon-x=17;icon-y=10;left=1;scr...")


I Click Sell, nothing happens.


Any pointers?

Nov 23 2015, 12:25 pm
R doesn't exist(null) and is null resulting in the error.
Nov 23 2015, 12:28 pm
But R does exist.

But I'm sure if I defined it var/obj/Item/clothing/R it would give the same error.
Nov 23 2015, 12:29 pm
After this line

var/obj/Item/R = input("What would you like to buy?","Shopkeep",text)in contents


Put

world << "R = [R.name]"


What does it output?
Nov 23 2015, 12:29 pm
 
 mob
    proc
        Installshop(var/obj/Item/clothing/I)
            for(var/mob/NPC/shopkeeper/M in world)
                I+=M.contents


The Installshop proc btw, this is what I use to throw the clothes in the shopkeepers contents.
Nov 23 2015, 12:47 pm (Edited on Nov 23 2015, 12:53 pm)
For fucks sake..
/mob/npc/shopkeeper
    icon='shopkeeper.dmi'
    attackable = 0
    layer = 50
    density = 1

    Vegeta{icon_state="vegeta"}

What exactly are you trying to accomplish here?
var/obj/Item/R = input("What would you like to buy?","Shopkeep",text)in contents

The reason R is null is because it was never created/initialized. You need to create it before u do anything with it
Nov 23 2015, 12:51 pm
In response to Kozuma3
Kozuma3 wrote:
After this line

var/obj/Item/R = input("What would you like to buy?","Shopkeep",text)in contents

Put

world << "R = [R.name]"

What does it output?

Didn't get anything in the output, instead it gave mthe same error this time pointing to line .46 which is the line where I inputted- 
world<<"R = [R.name]"


I don't even think any executes after it labels the var.
Nov 23 2015, 12:53 pm
In response to HaxRp
HaxRp wrote:
Didn't get anything in the output, instead it gave mthe same error this time pointing to line .46 which is the line where I inputted-
world<<"R = [R.name]"

I don't even think any executes after it labels the var.

That means R is null and not being set properly.
Nov 23 2015, 12:56 pm
 
 var/obj/Item/R = input("What would you like to buy?","Shopkeep",text)in contents
So this is an incorrect way to set?


I basically just want it so it reads all the items in the Shopkeepers contents for the user to catalog through for buying.
Nov 23 2015, 1:00 pm
In response to HaxRp
Is each item created or are you only retrieving their types?
Nov 23 2015, 1:06 pm
If you mean


obj/item

1

2

3


Then yes, I figured maybe typesof would work too but I wanted to find a shortcut aside from doing all that and including lists and what not.
Nov 23 2015, 1:07 pm
Best response
When the world boots up you could loop through the types and add the created item to a global list to retrieve from.
Nov 23 2015, 1:08 pm
Yeah i know that method, was seeing if there was a more simple way. Guess not xD
Nov 23 2015, 1:09 pm
Learn from this
/mob/verb/check()
    var/obj/items = locate() in usr.contents
    if(items)
        for(items in usr.contents)
            world<<items
    else
        alert("no items")

/obj/items
    icon='items.dmi'
    apple{icon_state="apple"}
    orange{icon_state="orange"}

/mob/verb
    give_apple()
        usr.contents += new/obj/items/apple
        world<<"++apple"
    give_orange()
        usr.contents += new/obj/items/orange
        world<<"++orange"
Nov 23 2015, 1:12 pm
In response to GreatPirateEra
I personally don't recommend using usr in those verbs.
Also, I don't understand why you would do the for() that way.
Nov 23 2015, 1:12 pm
In response to GreatPirateEra
GreatPirateEra wrote:
Learn from this
> /mob/verb/check()
>   var/obj/items = locate() in usr.contents
>   if(items)
>       for(items in usr.contents)
>           world<<items
>   else
>       alert("no items")
>
> /obj/items
>   icon='items.dmi'
>   apple{icon_state="apple"}
>   orange{icon_state="orange"}
>
> /mob/verb
>   give_apple()
>       usr.contents += new/obj/items/apple
>       world<<"++apple"
>   give_orange()
>       usr.contents += new/obj/items/orange
>       world<<"++orange"


Appreciated.
Nov 23 2015, 1:21 pm
In response to Kozuma3
Just something I did really quick on my phone. Wasn't tested but it should work. Anyways, I added upon it a little to demonstrate how u can get it's variables
mob/verb/check()
    var/obj/items/item = new
    item = locate() in usr.contents
    if(item)
        for(item)
            world<<"[item]: cost = [item.cost]"
    
    else
        alert("no items")

/obj/items
    icon='items.dmi'
    var/cost = 0
    apple{icon_state="apple";cost=5}
    orange{icon_state="orange";cost=10}

mob/verb
    give_fruits()
        usr.contents += new/obj/items/apple
        world<<"++apple"
        usr.contents += new/obj/items/orange
        world<<"++orange"
Nov 24 2015, 12:36 pm
In response to Kozuma3
Kozuma3 wrote:
I personally don't recommend using usr in those verbs.
Also, I don't understand why you would do the for() that way.

Kozuma is telling the truth. Use src instead of usr for this. Of additional note, why are you 
locate() in usr.contents
? Seems awfully redundant.
Nov 24 2015, 3:45 pm
In response to Somepotato
In my defense, I did state this was done rather quickly on my mobile device xD. Looking back at it, there are a couple of things I'd change. Regardless, it did demonstrate how to go about accessing an object's variables, meaning the snippet served it's purpose. Sure using usr in this particular case isn't safe, but I wasn't thinking about safety as I wrote this down.