Lua AIs: use ai_helper get_unit functions where applicable

The ai_helper functions are optimized for speed (as much as possible in a general setting) and do all the necessary tests.  For example, get_units_with_attacks() checks both whether the unit has attacks left, and whether it has any attacks in the first place.

(cherry-picked from commit 75843541bc)

data/ai/lua/ca_grab_villages.lua

@@ -13,9 +13,7 @@ function ca_grab_villages:evaluation(cfg, data)
     if AH.print_eval() then AH.print_ts('     - Evaluating grab_villages CA:') end
 
     -- Check if there are units with moves left
-    local units = wesnoth.get_units { side = wesnoth.current.side, canrecruit = 'no',
-        formula = 'movement_left > 0'
-    }
+    local units = AH.get_units_with_moves { side = wesnoth.current.side, canrecruit = 'no' }
     if (not units[1]) then
         if AH.print_eval() then AH.done_eval_messages(start_time, ca_name) end
         return 0

data/ai/lua/ca_move_to_any_enemy.lua

@@ -13,10 +13,9 @@ function ca_move_to_any_enemy:evaluation(cfg, data)
     local start_time, ca_name = wesnoth.get_time_stamp() / 1000., 'move_to_any_enemy'
     if AH.print_eval() then AH.print_ts('     - Evaluating move_to_any_enemy CA:') end
 
-    local units = wesnoth.get_units {
+    local units = AH.get_units_with_moves {
         side = wesnoth.current.side,
-        canrecruit = 'no',
-        formula = 'movement_left > 0'
+        canrecruit = 'no'
     }
 
     if (not units[1]) then

data/ai/lua/ca_retreat_injured.lua

@@ -11,10 +11,7 @@ function ca_retreat_injured:evaluation(cfg, data)
     local start_time, ca_name = wesnoth.get_time_stamp() / 1000., 'retreat_injured'
     if AH.print_eval() then AH.print_ts('     - Evaluating retreat_injured CA:') end
 
-    local units = wesnoth.get_units {
-        side = wesnoth.current.side,
-        formula = 'movement_left > 0'
-    }
+    local units = AH.get_units_with_moves { side = wesnoth.current.side }
     local unit, loc = R.retreat_injured_units(units)
     if unit then
         retreat_unit = unit

data/ai/lua/ca_spread_poison.lua

@@ -12,8 +12,7 @@ function ca_spread_poison:evaluation(cfg, data)
 
     -- If a unit with a poisoned weapon can make an attack, we'll do that preferentially
     -- (with some exceptions)
-    local poisoners = AH.get_live_units { side = wesnoth.current.side,
-        formula = 'attacks_left > 0',
+    local poisoners = AH.get_units_with_attacks { side = wesnoth.current.side,
         { "filter_wml", {
             { "attack", {
                 { "specials", {

data/ai/lua/ca_village_hunt.lua

@@ -30,10 +30,9 @@ function ca_village_hunt:evaluation(cfg, data)
         return 0
     end
 
-    local units = wesnoth.get_units {
+    local units = AH.get_units_with_moves {
         side = wesnoth.current.side,
-        canrecruit = false,
-        formula = 'movement_left > 0'
+        canrecruit = false
     }
 
     if not units[1] then
@@ -46,10 +45,9 @@ function ca_village_hunt:evaluation(cfg, data)
 end
 
 function ca_village_hunt:execution(cfg, data)
-    local unit = wesnoth.get_units({
+    local unit = AH.get_units_with_moves({
         side = wesnoth.current.side,
-        canrecruit = false,
-        formula = 'movement_left > 0'
+        canrecruit = false
     })[1]
 
     if AH.print_exec() then AH.print_ts('   Executing village_hunt CA') end

data/campaigns/Eastern_Invasion/ai/ca_ogres_flee.lua

@@ -6,18 +6,14 @@ local M = wesnoth.map
 local ca_ogres_flee = {}
 
 function ca_ogres_flee:evaluation()
-    local units = wesnoth.get_units { side = wesnoth.current.side,
-        formula = 'movement_left > 0'
-    }
+    local units = AH.get_units_with_moves { side = wesnoth.current.side }
 
     if (not units[1]) then return 0 end
     return 110000
 end
 
 function ca_ogres_flee:execution()
-    local units = wesnoth.get_units { side = wesnoth.current.side,
-        formula = 'movement_left > 0'
-    }
+    local units = AH.get_units_with_moves { side = wesnoth.current.side }
 
     local units_noMP = wesnoth.get_units { side = wesnoth.current.side,
         formula = 'movement_left = 0'

data/campaigns/The_Rise_Of_Wesnoth/ai/ca_aggressive_attack_no_suicide.lua

@@ -6,10 +6,7 @@ local ca_aggressive_attack_no_suicide = {}
 
 function ca_aggressive_attack_no_suicide:evaluation(cfg, data)
 
-    local units = wesnoth.get_units {
-        side = wesnoth.current.side,
-        formula = 'attacks_left > 0'
-    }
+    local units = AH.get_units_with_attacks { side = wesnoth.current.side }
     if (not units[1]) then return 0 end
 
     -- Get all possible attacks

data/campaigns/The_Rise_Of_Wesnoth/ai/ca_retreat.lua

@@ -7,10 +7,7 @@ local retreat = {}
 
 function retreat:evaluation(cfg, data)
 
-    local units = wesnoth.get_units {
-        side = wesnoth.current.side,
-        formula = 'movement_left > 0'
-    }
+    local units = AH.get_units_with_moves { side = wesnoth.current.side }
     if (not units[1]) then return 0 end
 
     local unit, dst, enemy_threat = R.retreat_injured_units(units)