Initial implementation of the [select_unit] tag per bug #16819

Optional attributes: fire_event (def. no), hilight (def. yes)

Part of this is broken since I haven't figured out yet how to make it
possible to draw the movement ranges etc. when hilight=yes; apparently
some pathfinder stuff is required per mouse_events.cpp:280 and 284...

changelog

@@ -69,6 +69,8 @@ Version 1.9.1+svn:
    * added new parameters directional_x and directional_y to animations
    * added new parameters auto_vflip and auto_hflip to animations
    * Made it so that units affected by [hide_unit] don't appear on the minimap (FR #16796)
+   * New [select_unit] tag, with optional fire_event (def. no) and hilight_hex (def. yes)
+     attributes (FR #16819)
  * Miscellaneous and bugfixes:
    * Changed: Lowered severity of some gui2 timer log messages.
    * Units created in debug mode now play their recruit animation (FR #16766).

data/lua/wml-tags.lua

@@ -279,6 +279,20 @@ function wml_actions.scroll_to_unit(cfg)
 	wesnoth.scroll_to_tile(u.x, u.y, cfg.check_fogged)
 end
 
+function wml_actions.select_unit(cfg)
+	local u = wesnoth.get_units(cfg)[1]
+	if not u then return end
+	local fire_event = cfg.fire_event
+	local hilight = (cfg.hilight or true)
+
+	wesnoth.select_hex(u.x, u.y)
+
+	if hilight then wesnoth.hilight_hex(u.x, u.y) end
+	if fire_event then
+		wesnoth.fire_event("select", u.x, u.y)
+	end
+end
+
 function wml_actions.unit_overlay(cfg)
 	local img = cfg.image
 	for i,u in ipairs(wesnoth.get_units(cfg)) do

data/scenario-test.cfg

@@ -631,6 +631,33 @@ My best advancement costs $next_cost gold and I'm $experience|% there."
         [/lua]
     [/event]
 
+    [event]
+        name=test1
+        first_time_only=no
+        [select_unit]
+            type=Elvish Avenger
+            fire_event=yes
+        [/select_unit]
+    [/event]
+
+    [event]
+        name=select
+        first_time_only=no
+        [filter]
+            type=Elvish Avenger
+            [filter_wml]
+                [status]
+                    petrified=yes
+                [/status]
+            [/filter_wml]
+        [/filter]
+
+        [message]
+            speaker=unit
+            message="Oh hi"
+        [/message]
+    [/event]
+
     [event]
         name=prestart
         [time_area]