From fc4a6a44ebfff75cbdf0a4b62b63d7b8b5f7eacc Mon Sep 17 00:00:00 2001
From: h-v-smacker <hans-von-smacker+github@gmail.com>
Date: Mon, 7 May 2018 08:02:36 +0300
Subject: Resolution of API ambiguity

---
 api.txt  | 31 +++++++++++++++++++++------
 init.lua | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/api.txt b/api.txt
index bc450fd..e399bdc 100644
--- a/api.txt
+++ b/api.txt
@@ -14,7 +14,9 @@ Function Usage
 Adding Crops
 ------------
 
-bonemeal:add_crop({ nodename_start, growing_steps, seed_name })
+bonemeal:add_crop({
+	{ nodename_start, growing_steps, seed_name }
+})
 
 This command is used to add new crops for bonemeal to work on.
 
@@ -29,7 +31,9 @@ bonemeal:add_crop({
 Adding Saplings
 ---------------
 
-bonemeal:add_sapling({ sapling_node, function, soil_type[sand, dirt, nodename] })
+bonemeal:add_sapling({
+	{ sapling_node, function, soil_type[sand, dirt, nodename] }
+})
 
 This command will add new saplings for bonemeal to grow on sand, soil or a
 specified node type.
@@ -43,16 +47,31 @@ bonemeal:add_sapling({
 Adding Dirt Decoration
 ----------------------
 
-bonemeal:add_deco({ dirt_node, {grass_node_list}, {decor_node_list} })
+bonemeal:add_deco({
+	{ dirt_node, {grass_node_list}, {decor_node_list} }
+})
 
 This command will add grass and decoration to specific dirt types, use "" to
-add an empty node.
+add an empty node. If some decorations have been already defined for this dirt type, new
+will be added to the respective list. All empty ("") entries will be added regardless,
+which allows to decrease the frequency of decoration emergence, if needed.
 
 e.g.
 
-bonemeal:add_deco({"default:dirt_with_dry_grass", {"default:dry_grass_1", ""},
-	{"flowers:rose", "flowers:viola"} })
+bonemeal:add_deco({
+	{"default:dirt_with_dry_grass", {"default:dry_grass_1", ""}, 
+		{"flowers:rose", "flowers:viola"} }
+})
+
+Thus, add_deco() always adds (to) a definition, and never overrides. To discard an existing
+definiton in favor of the new one, use
+	
+bonemeal:set_deco({
+	{ dirt_node, {grass_node_list}, {decor_node_list} }
+})
 
+This command will set decoration for a given dirt type, fully replacing any existing definition.
+	
 
 Global ON_USE Function
 ----------------------
diff --git a/init.lua b/init.lua
index f4f8f32..35526f8 100644
--- a/init.lua
+++ b/init.lua
@@ -290,13 +290,83 @@ end
 -- add grass and flower/plant decoration for specific dirt types
 --  {dirt_node, {grass_nodes}, {flower_nodes}
 -- e.g. {"default:dirt_with_dry_grass", dry_grass, flowers}
+-- if an entry already exists for a given dirt type, it will add new entries and all empty
+-- entries, allowing to both add decorations and decrease their frequency.
 function bonemeal:add_deco(list)
 
-	for n = 1, #list do
-		table.insert(deco, list[n])
+	for l = 1, #list do
+    
+		for n = 1, #deco do
+
+			-- update existing entry
+			if list[l][1] == deco[n][1] then
+				
+				-- adding grass types
+				for _,extra in ipairs(list[l][2]) do
+					if extra ~= "" then
+						for __,entry in ipairs(deco[n][2]) do
+							if extra == entry then
+								extra = false
+								break
+							end
+						end
+					end
+					if extra then
+						table.insert(deco[n][2], extra)
+					end
+				end
+				
+				-- adding decoration types
+				for _,extra in ipairs(list[l][3]) do
+					if extra ~= "" then
+						for __,entry in ipairs(deco[n][3]) do
+							if extra == entry then
+								extra = false
+								break
+							end
+						end
+					end
+					if extra then
+						table.insert(deco[n][3], extra)
+					end
+				end
+    
+				list[l] = false
+				break
+			end
+    
+		end
+    
+		if list[l] then
+			table.insert(deco, list[l])
+		end
+	
 	end
 end
 
+-- definitively set a decration scheme
+-- this function will either add a new entry as is, or replace the existing one
+function bonemeal:set_deco(list)
+
+	for l = 1, #list do
+    
+		for n = 1, #deco do
+
+			-- replace existing entry
+			if list[l][1] == deco[n][1] then
+				deco[n][2] = list[l][2]
+				deco[n][3] = list[l][3]
+				list[l] = false
+				break
+			end
+		end
+    
+		if list[l] then
+			table.insert(deco, list[l])
+		end
+    
+	end
+end
 
 -- global on_use function for bonemeal
 function bonemeal:on_use(pos, strength, node)
-- 
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