Add [message]image_pos=left|right

This is meant to replace ~RIGHT() and also the newer ~LEFT(),
with one exception: ~RIGHT() will still be the standard way to
make a unit's portrait go on the right by default.

changelog

@@ -79,6 +79,7 @@ Version 1.13.4+dev:
      (This means [advancement], [object], and [trait] tags.)
    * All looping tags now give an error if they contain no [do] tag.
      (They may contain multiple [do] tags, however.)
+   * Add [message]image_pos=left|right, which mostly supercedes ~RIGHT()
    * AiWML:
      * Filters within [micro_ai] can now use $this_unit, which was previously
        impossible due to the config being prematurely parsed.

data/core/units/humans/Mage_Silver.cfg

@@ -161,7 +161,7 @@ Silver magi are often more physically adept than other magi, and their skills ar
         name= _ "female^Silver Mage"
         gender=female
         image="units/human-magi/silver-mage+female.png"
-        profile="portraits/humans/mage-silver+female.png~LEFT()"
+        profile="portraits/humans/mage-silver+female.png"
         die_sound={SOUND_LIST:HUMAN_FEMALE_DIE}
         {DEFENSE_ANIM "units/human-magi/silver-mage+female-defend.png" "units/human-magi/silver-mage+female.png" {SOUND_LIST:HUMAN_FEMALE_HIT} }
         [attack_anim]

data/lua/wml/message.lua

@@ -11,32 +11,29 @@ end
 local function get_image(cfg, speaker)
 	local image = cfg.image
 	local left_side = true
-	
-	if image == "~RIGHT()" then
-		image = nil
-		left_side = false
-	end
 
 	if speaker and (image == nil or image == "") then
 		image = speaker.portrait
 	end
 
-	if image == "none" or image == nil then
-		return "", true
-	end
-
+	-- Note: This is deprecated except for use to set default alignment in portraits
+	-- (Move it into the above if statement later)
 	if image:find("~RIGHT%(%)") then
 		left_side = false
 		-- The percent signs escape the parentheses for a literal match
 		image = image:gsub("~RIGHT%(%)", "")
 	end
 
-	if image:find("~LEFT%(%)") then
-		-- This currently overrides ~RIGHT()
-		-- Use if a portrait defaults to ~RIGHT(),
-		-- or in [unit_type] to force it to left.
+	if cfg.image_pos == 'left' then
 		left_side = true
-		image = image:gsub("~LEFT%(%)", "")
+	elseif cfg.image_pos == 'right' then
+		left_side = false
+	elseif cfg.image_pos ~= nil then
+		helper.wml_error('Invalid [message]image_pos - should be left or right')
+	end
+
+	if image == "none" or image == nil then
+		return "", true
 	end
 
 	return image, left_side