stop any casting and begin channeling Arcane Missiles only if Arcane Missiles is not already being channeled
if you get fancy with it you can also add a condition that Arcane Missiles may only start if Arcane Missiles AND Evocation aren't being channeled, to prevent any accidental mana loss as well
the following is a description of an apparently impossible macro, so don't bother unless you're a macro magician
ok, basically I'm trying to build a very neat arcane mage macro, but need someone who knows macros to help me
it's a perfect macro for arcane mages who wanna make sure they don't miss a tick of arcane missiles by starting to cast a new spell before it finished casting, it's got a few elements though
basically i want it to cast Arcane Missiles if Arcane Missiles is available, but it should not start channeling if the previous Arcane Missiles hasn't finished channeling OR if Arcane Missiles is not available again by the time it finished channeling - cast Arcane Blast instead
i have only figured out this part, but im not sure how to add all the other elements to it
/cast [nochanneling:Arcane Missiles] Arcane Missiles
PS
the purpose of this macro is not at all to make a 1 button arcane spam, in fact spamming this button will not provide high dps at all, this macro will replace the Arcane Missiles button only, so you will still need to use Arcane Blast manually when you're in burning phase or when you just wanna get 2-4 stacks of AB without casting AM. this macro will eliminate the following:
1. loss of mana ( for example, when you finish casting your 3rd AB and you know you don't want to cast a 4th AB because it will cost you too much mana, BUT you don't know whether you will have Arcane Missiles available until you're already casting the next AB; you end up with 2 options - queue up the next AB by spamming the AB key at the end of your cast, so that the 4th AB starts casting immediately after, this way you only find out whether your 3rd AB had procced Arcane Missiles while casting the next mana-expensive AB and you will be able to start casting Arcane Missiles only after it has completed, but you will have wasted valuable mana OR if you found out Arcane Missiles had procced after starting to cast the next AB - you can cancel casting AB and begin casting Arcane Missiles, but you lose the time you could have already been casting Arcane Missiles
2. downtime between spells - because you will not have to lose time you could have been casting Arcane Missiles after you decide not to cast a mana-expensive AB(explained above)
3. loss of dps from cutting off arcane missiles too early, which happens to a lot of people because they don't know their exact latency at every moment