I started with the desire to fix issue 634. It sounded like a simple issue, right? Well one complete rewrite of how equipping and stripping works later, this commit fixes issue 645

Code-wide changes: /mob -level procs:
equip_if_possible() is now known as equip_to_slot_or_del() to prevent confusion with equip_to_slot_if_possible() and to better describe what it does.

equip_to_slot_if_possible(item, slot, del_on_fail, disable_warning, redraw_mob)

equip_to_appropriate_slot() is now a /mob - level proc.

equip_to_slot() is an unsafe proc, which just handles the final step of actually getting an item onto the mob. It has no checks of whether it can or can't do that. Use equip_to_slot_if_possible() for that purpose.

New /obj/item -level proc:
/obj/item/proc/mob_can_equip(M as mob, slot, disable_warning = 0)

This proc can be used to determine whehter a mob can pick up an item from the item's side.

Carn, I'll need you to review code/modules/mob/living/carbon/human/inventory.dm to ensure that I'm not redrawing the mob too many times.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@4423 316c924e-a436-60f5-8080-3fe189b3f50e

code/game/objects/items/item.dm

@@ -17,14 +17,11 @@
 
 // called after an item is placed in an equipment slot
 // user is mob that equipped it
-// slot is text of slot type e.g. "head"
+// slot uses the slot_X defines found in setup.dm
 // for items that can be placed in multiple slots
 // note this isn't called during the initial dressing of a player
 /obj/item/proc/equipped(var/mob/user, var/slot)
 	return
-//
-// ***TODO: implement unget_active_hand()
-//
 
 /obj/item/proc/afterattack()
 

code/game/objects/items/tk_grab.dm

@@ -22,7 +22,7 @@
 
 	//stops TK grabs being equipped anywhere but into hands
 	equipped(var/mob/user, var/slot)
-		if( (slot=="l_hand") || (slot=="r_hand") )	return
+		if( (slot == slot_l_hand) || (slot== slot_r_hand) )	return
 		del(src)
 		return
 
@@ -115,7 +115,7 @@
 		return 1
 */
 
-//equip_if_possible(obj/item/W, slot, del_on_fail = 1)
+//equip_to_slot_or_del(obj/item/W, slot, del_on_fail = 1)
 /*
 		if(istype(user, /mob/living/carbon))
 			if(user:mutations & TK && get_dist(source, user) <= 7)

code/game/objects/items/weapons/twohanded.dm

@@ -23,6 +23,14 @@
 	name = "[initial(name)] (Wielded)"
 	update_icon()
 
+/obj/item/weapon/twohanded/mob_can_equip(M as mob, slot)
+	//Cannot equip wielded items.
+	if(wielded)
+		M << "<span class='warning'>Unwield the [initial(name)] first!</span>"
+		return 0
+
+	return ..()
+
 /obj/item/weapon/twohanded/dropped(mob/user as mob)
 	//handles unwielding a twohanded weapon when dropped as well as clearing up the offhand
 	if(user)