out of combat restriction.
I've played around with these values of progressionIndex, the 3 Skill/Line/Index, and that AbilityIndex that can be used alone : only that last one won't make you errors with the different destructions schools. (doesn't make easy to find functions for it when it has the same name as the other one)
I think the Skill/Line/AbilityIndex are reserved to determine the place of the skill in the tree in the skill window the real skill data comes from ProgressionIndex and what circonian wrote.
Only the defaut skills are registered when browsing them like I did (i.e : my frost skills throw a nil error) so you should definitively use Circonian's method.
though if you allow different bars with different weapons, you may consider mixing both methods for the destruction staves.
I've dumped all my skills to see how it works... if hasprogression is false, progressionIndex is 2, the name of the skill is wrong (once it always displayed Mage's Fury, another reload it was lightening splash etc...) but here what can interest you :
Lua Code:
[40964] = -- slotted in the bar as frost skill : id 40967, doesn't appear in the dump, but has progressionIndex = 8 too. so you can relate both.
{
[1] = 2,
[2] = 5,
[3] = 1,
["unMorphedName"] = "Destructive Touch",
["morphChoice"] = 0,
["hasProgression"] = true,
["progressionIndex"] = 8,
["browsercount"] = 71,
["countHasProgressionTrue"] = 9,
},
counts were there to try to figure out how the progressionIndex is set, but it seems to have no relation with the skill order.
So to sum up: Circonian's method will work always with no error (as the realAbilityIndex comes from the progressionIndex and they are shared between different forms of the skill, it's the default form that should be stored)
Only problem : if you want to show the right icon in your interface when selected with a different magic school in the set. checking for functions.
OK heads up : This :
GetAbilityIdByIndex(realAbilityIndex)
returns the right skill id (ice / lightening etc) for the currently equipped weapon.