Editing WoW:Useful macros (section)

=== Set Swap ===
 /equipset [noequipped:Fishing Pole, mod] Fishing; [noequipped:Fishing Pole, nomod, spec:1] [mod, spec:1] Set1; [noequipped:Fishing Pole, nomod, spec:2] [mod, spec:2] Set2
 /use [equipped:Fishing Pole, nomod] Fishing

*Uses the Blizzard Equipment Manager
**Requires one set called Fishing that contains your fishing pole and any equipment you want to wear while fishing (fishing hat, gloves or similar) and two sets that fit your specs (replace Set1 and Set2 with your names)
If your fishing set is equipped, click will cast Fishing, mod-click will equip the set fitting your current spec. Otherwise, mod-click will equip your fishing set, normal click will equip the spec-relevant set.

Alternate version for toons with just one spec or equipment set:
 /equipset [noequipped:Fishing Pole, mod] Fishing;  [noequipped:Fishing Pole, nomod] [mod] Set1
 /use [equipped:Fishing Pole, nomod] Fishing