WotLK Mouseover macro

[Hooba2]

#showtooltip
/cast [@mouseover, @target, @player] Healing Wave

Can you write correct simple macro for heal with priority mouseover >> target >> (no target or target enemy=player)
Now my macro heal only myself

[Kinniak]

/cast [@mouseover, harm, exists] Purge; Purge

[Hooba2]

not working

[Shred]

Granted this can probably be optimised, but it works

/cast [@mouseover, noharm, exists] Healing Wave
/cast [@target, noharm, exists] Healing Wave
/cast [@player] Healing Wave