Random Recruiting Micro AI: code cleanup

data/ai/micro_ais/cas/ca_recruit_random.lua

@@ -1,6 +1,6 @@
 local AH = wesnoth.require("ai/lua/ai_helper.lua")
 
-local recruit
+local recruit_type
 
 local ca_recruit_random = {}
 
@@ -21,12 +21,13 @@ function ca_recruit_random:evaluation(ai, cfg)
             { "and", {
                 x = leader.x, y = leader.y, radius = 200,
                 { "filter_radius", { terrain = 'C*,K*,C*^*,K*^*,*^K*,*^C*' } }
-            }}
+            } }
         }
     }
+
     local no_space = true
-    for i,c in ipairs(castle.locs) do
-        local unit = wesnoth.get_unit(c[1], c[2])
+    for _,loc in ipairs(castle.locs) do
+        local unit = wesnoth.get_unit(loc[1], loc[2])
         if (not unit) then
             no_space = false
             break
@@ -35,75 +36,73 @@ function ca_recruit_random:evaluation(ai, cfg)
     if no_space then return 0 end
 
     -- Set up the probability array
-    local prob, prob_sum  = {}, 0
+    local probabilities, probability_sum  = {}, 0
 
     -- Go through all the types listed in [probability] tags (which can be comma-separated lists)
-    for i,tmp in ipairs(cfg.type) do
-        tmp = AH.split(tmp, ",")
-        for j,t in ipairs(tmp) do
+    -- Types and probabilities are put into cfg.type and cfg.prob arrays by micro_ai_wml_tag.lua
+    for ind,types in ipairs(cfg.type) do
+        types = AH.split(types, ",")
+        for _,typ in ipairs(types) do  -- 'type' is a reserved keyword in Lua
             -- If this type is in the recruit list, add it
-            for k,r in ipairs(wesnoth.sides[wesnoth.current.side].recruit) do
-                if (r == t) then
-                    prob[t] = { value = cfg.prob[i] }
-                    prob_sum = prob_sum + cfg.prob[i]
+            for _,recruit in ipairs(wesnoth.sides[wesnoth.current.side].recruit) do
+                if (recruit == typ) then
+                    probabilities[typ] = { value = cfg.prob[ind] }
+                    probability_sum = probability_sum + cfg.prob[ind]
                     break
                 end
             end
         end
     end
 
     -- Now we add in all the unit types not listed in [probability] tags
-    for i,r in ipairs(wesnoth.sides[wesnoth.current.side].recruit) do
-        if (not prob[r]) then
-            prob[r] = { value = 1 }
-            prob_sum =prob_sum + 1
+    for _,recruit in ipairs(wesnoth.sides[wesnoth.current.side].recruit) do
+        if (not probabilities[recruit]) then
+            probabilities[recruit] = { value = 1 }
+            probability_sum = probability_sum + 1
         end
     end
 
     -- Now eliminate all those that are too expensive (unless cfg.skip_low_gold_recruiting is set)
     if cfg.skip_low_gold_recruiting then
-        for typ,pr in pairs(prob) do
+        for typ,probability in pairs(probabilities) do  -- 'type' is a reserved keyword in Lua
             if (wesnoth.unit_types[typ].cost > wesnoth.sides[wesnoth.current.side].gold) then
-                --print('Eliminating:', typ)
-                prob_sum = prob_sum - pr.value
-                prob[typ] = nil
+                probability_sum = probability_sum - probability.value
+                probabilities[typ] = nil
             end
         end
     end
 
-    -- Now set up the min/max values for each type
-    -- This needs to be done manually as the order of pairs() is not guaranteed
-    local cum_prob, n_recruits = 0, 0
-    for typ,pr in pairs(prob) do
-        prob[typ].p_i = cum_prob
-        cum_prob = cum_prob + pr.value / prob_sum * 1e6
-        prob[typ].p_f = cum_prob
-        n_recruits = n_recruits + 1
+    -- Now set up the cumulative probability values for each type
+    -- Both min and max need to be set as the order of pairs() is not guaranteed
+    local cum_prob = 0
+    for typ,probability in pairs(probabilities) do
+        probabilities[typ].p_i = cum_prob
+        cum_prob = cum_prob + probability.value
+        probabilities[typ].p_f = cum_prob
     end
 
-    -- Now we're ready to pick on of those
     -- We always call the exec function, no matter if the selected unit is affordable
     -- The point is that this will blacklist the CA if an unaffordable recruit was
     -- chosen -> no cheaper recruits will be selected in subsequent calls
-    if (n_recruits > 0) then
-        local rand_prob = math.random(1e6)
-        for typ,pr in pairs(prob) do
-            if (pr.p_i <= rand_prob) and (rand_prob < pr.p_f) then
-                recruit = typ
+    if (cum_prob > 0) then
+        local rand_prob = math.random(cum_prob)
+        for typ,probability in pairs(probabilities) do
+            if (probability.p_i < rand_prob) and (rand_prob <= probability.p_f) then
+                recruit_type = typ
                 break
             end
         end
     else
-        recruit = wesnoth.sides[wesnoth.current.side].recruit[1]
+        recruit_type = wesnoth.sides[wesnoth.current.side].recruit[1]
     end
 
     return cfg.ca_score
 end
 
 function ca_recruit_random:execution(ai, cfg)
     -- Let this function blacklist itself if the chosen recruit is too expensive
-    if wesnoth.unit_types[recruit].cost <= wesnoth.sides[wesnoth.current.side].gold then
-        AH.checked_recruit(ai, recruit)
+    if wesnoth.unit_types[recruit_type].cost <= wesnoth.sides[wesnoth.current.side].gold then
+        AH.checked_recruit(ai, recruit_type)
     end
 end