Lua AIs: use new syntax for iterating over attacks

This is both simpler and faster than the old syntax.

data/ai/lua/ai_helper.lua

@@ -1146,11 +1146,9 @@ end
 function ai_helper.has_weapon_special(unit, special)
     -- Returns true/false depending on whether @unit has a weapon with special @special
     -- Also returns the number of the first weapon with this special
-    local weapon_number = 0
-    for att in H.child_range(unit.__cfg, 'attack') do
-        weapon_number = weapon_number + 1
-        for sp in H.child_range(att, 'specials') do
-            if H.get_child(sp, special) then
+    for weapon_number,att in ipairs(unit.attacks) do
+        for _,sp in ipairs(att.specials) do
+            if (sp[1] == special) then
                 return true, weapon_number
             end
         end

data/ai/micro_ais/cas/ca_bottleneck_attack.lua

@@ -17,10 +17,7 @@ function ca_bottleneck_attack:evaluation(cfg, data)
         local targets = AH.get_attackable_enemies { { "filter_adjacent", { id = attacker.id } } }
 
         for _,target in ipairs(targets) do
-            local n_weapon = 0
-            for weapon in H.child_range(attacker.__cfg, "attack") do
-                n_weapon = n_weapon + 1
-
+            for n_weapon,weapon in ipairs(attacker.attacks) do
                 local att_stats, def_stats = wesnoth.simulate_combat(attacker, n_weapon, target)
 
                 local rating

data/ai/micro_ais/cas/ca_bottleneck_move.lua

@@ -379,9 +379,7 @@ function ca_bottleneck_move:evaluation(cfg, data)
                 if (attack.x == loc[1]) and (attack.y == loc[2]) and
                     (unit.max_experience - unit.experience <= 8 * attack.defender_level)
                 then
-                    local n_weapon = 0
-                    for weapon in H.child_range(unit.__cfg, "attack") do
-                        n_weapon = n_weapon + 1
+                    for n_weapon,weapon in ipairs(unit.attacks) do
                         local att_stats, def_stats = BC.simulate_combat_loc(unit, { attack.x, attack.y }, attack.defender, n_weapon)
 
                         -- Execute level-up attack when:

data/ai/micro_ais/cas/ca_messenger_move.lua

@@ -93,10 +93,7 @@ function ca_messenger_move:execution(cfg)
 
     local max_rating, best_target, best_weapon = -9e99
     for _,target in ipairs(targets) do
-        local n_weapon = 0
-        for weapon in H.child_range(messenger.__cfg, "attack") do
-            n_weapon = n_weapon + 1
-
+        for n_weapon,weapon in ipairs(messenger.attacks) do
             local att_stats, def_stats = wesnoth.simulate_combat(messenger, n_weapon, target)
 
             local rating = -9e99

data/ai/micro_ais/cas/ca_protect_unit_attack.lua

@@ -49,11 +49,8 @@ function ca_protect_unit_attack:evaluation(cfg)
                         max_counter_damage = max_counter_damage + counter_damage_table[str]
                     else  -- if not, calculate it and save value
                         -- Go thru all weapons, as "best weapon" might be different later on
-                        local n_weapon = 0
                         local min_hp = unit.hitpoints
-                        for weapon in H.child_range(enemy_attack.enemy.__cfg, "attack") do
-                            n_weapon = n_weapon + 1
-
+                        for n_weapon,weapon in ipairs(enemy_attack.enemy.attacks) do
                             -- Terrain does not matter for this, we're only interested in the maximum damage
                             local att_stats, def_stats = wesnoth.simulate_combat(enemy_attack.enemy, n_weapon, unit)