Check if a specific addon is enabled?

[SnowmanDK]

Is there a way to check for this?
I ask as I am trying to integrate support for Item Saver in my Bank Manager Revived.
Item Saver uses a global variable which I pull (ItemSaver_IsItemSaved(item.bag, item.slot)),
It returns 1 if the checked item is saved, otherwise nil.
I made that work fine, but when Item Saver is not enabled in AddOns, then I get a "function expected instead of nil" error.

So... I guess I need to make sure Item Saver is enabled in AddOns before even running this check.
Can this be done?

[Garkin]

Originally Posted by SnowmanDK Is there a way to check for this? I ask as I am trying to integrate support for Item Saver in my Bank Manager Revived. Item Saver uses a global variable which I pull (ItemSaver_IsItemSaved(item.bag, item.slot)), It returns 1 if the checked item is saved, otherwise nil. I made that work fine, but when Item Saver is not enabled in AddOns, then I get a "function expected instead of nil" error. So... I guess I need to make sure Item Saver is enabled in AddOns before even running this check. Can this be done?

It can be easily done. At first check if global function exists and if it does then use it.

if ItemSaver_IsItemSaved and ItemSaver_IsItemSaved(item.bag, item.slot) then
    --your code here
end

This is a function which I use in Dustman:

local function IsItemProtected(bagId, slotId)
   --pets
   local iconTexture = GetItemInfo(bagId, slotId)
   if iconTexture:lower():find("icons/pet_") then
      return true
   end
 
   --Item Saver support
   if ItemSaver_IsItemSaved and ItemSaver_IsItemSaved(bagId, slotId) then
      return true
   end
 
   --FCO ItemSaver support
   if FCOIsMarked and FCOIsMarked(GetItemInstanceId(bagId, slotId), -1) then
      return true
   end
 
   return false
end

[sirinsidiator]

you probably can check if the checkbox is checked in the addon panel, but I think it would be simpler to check if the function exists before calling it.

if(ItemSaver_IsItemSaved ~= nil) then ItemSaver_IsItemSaved(item.bag, item.slot) end

[SnowmanDK]

@sirinsidiator: I tried that solution and it also threw the same error.
@Garkin: Your solution worked (as always).

Thanks to both of you for the suggestions

[votan]

Hi.

In the Wiki is stated, that a callback of EVENT_ADD_ON_LOADED is called for all addons.
This is the reason why we always have to check for our own addon name.
Isn't that exactly what you need?

Cheers

[Randactyl]

Originally Posted by votan Hi. In the Wiki is stated, that a callback of EVENT_ADD_ON_LOADED is called for all addons. This is the reason why we always have to check for our own addon name. Isn't that exactly what you need? Cheers

I like this the best - especially if the addon you are checking for doesn't have any global functions.

Just add the addon to your OptionalDependsOn and then

if(addOnName == "otherAddon") then 
    flag = true
elseif(addOnName == "yourAddon") then
    EVENT_MANAGER:UnregisterForEvent("addonLoadedFunction", EVENT_ADD_ON_LOADED)
else
    return
end

I actually used a version of this for Advanced Filters to create a filter for Item Saver before I changed the way filters could be added.

[Sasky]

However, consider that Garkin's gets directly to the point: Is the required function there?
If an addon doesn't have any global functions, you're not going to be using one of its functions in your addon.

[SnowmanDK]

Just to clarify:
As I wrote in my initial post then I wanted to check if Item Saver was enabled, so my addon can take advantage of it's functions, but not fail if Item Saver is not even installed.

Problem was solved with Garkin's answer.

[votan]

Originally Posted by Sasky However, consider that Garkin's gets directly to the point: Is the required function there? If an addon doesn't have any global functions, you're not going to be using one of its functions in your addon.

I knew this discussion will come in the moment I pressed reply.
The question was "Check if a specific addon is enabled?", not "Check if a global function is available?".
There are scenarios, where "Always-check-before-calling" is absolutly sufficient.
And there are scenarios, where such a check should be done once and different functions are registered to be called.
Mainly if used in large, nested loops.

Originally Posted by SnowmanDK Just to clarify: As I wrote in my initial post then I wanted to check if Item Saver was enabled, so my addon can take advantage of it's functions, but not fail if Item Saver is not even installed. Problem was solved with Garkin's answer.

Nethertheless, as all is fine:
Sorry.