Added font_lib deprecation and corresponding notices in READMEs

3 files changed, 64 insertions, 4 deletions

diff --git a/README.md b/README.md
index 33af92b..13d287f 100644
--- a/README.md
+++ b/README.md
@@ -16,8 +16,16 @@ For more information, see the [forum topic](https://forum.minetest.net/viewtopic
 
 You can add fonts by installing fonts mod. Be aware that each font comes with numerous textures. This can result in slowing media downloading and/or client display.
 
-Font mods can be found here: 
+Font mods can be found here:
 
  * [Metro](https://github.com/pyrollo/display_modpack/tree/master/font_metro): A multipurpose font with many chars (uppercase, lowercase and accentuated latin letters, usual signs, cyrillic and greek letters).
  * [OldWizard](https://github.com/pyrollo/font_oldwizard): An old style gothic font.
  * [Botic](https://github.com/pyrollo/font_botic): A scifi style font.
+
+ ## Deprecation notice (for modders)
+
+ ### December 2018
+ Following object is deprecate, shows a warning in log when used:
+ * `font_lib` global table (use `font_api` global table instead);
+
+ This object will be removed in the future.
diff --git a/deprecation.lua b/deprecation.lua
new file mode 100644
index 0000000..5c0bed6
--- /dev/null
+++ b/deprecation.lua
@@ -0,0 +1,54 @@
+--[[
+	font_api mod for Minetest - Library to create textures with fonts and text
+	(c) Pierre-Yves Rollo
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+--]]
+
+-- Deprecation
+
+function deprecated_global_table(deprecated_global_name, replacement_global_name)
+	assert(type(deprecated_global_name) == 'string', "deprecated_global_name should be a string.")
+	assert(type(replacement_global_name) == 'string', "replacement_global_name should be a string.")
+	assert(deprecated_global_name ~= '', "deprecated_global_name should not be empty.")
+	assert(replacement_global_name ~= '', "replacement_global_name should not be empty.")
+	assert(rawget(_G, deprecated_global_name) == nil, "replacement global already exists.")
+	if _G[replacement_global_name] == nil then
+		print('warn_deprecated_functions: Warning, replacement global "'..replacement_global_name..'" does not exists.')
+		return
+	end
+	local meta = {
+		deprecated = deprecated_global_name,
+		replacement = replacement_global_name,
+		__index = function(table, key)
+			local meta = getmetatable(table)
+			local dbg = debug.getinfo(2, "lS")
+			minetest.log("warning", string.format('Warning: Accessing deprecated "%s" table, "%s" should be used instead (%s:%d).',
+				meta.deprecated, meta.replacement, (dbg.short_src or 'unknown'), (dbg.currentline or 0)))
+			return _G[meta.replacement][key]
+		end,
+		__newindex = function(table, key, value)
+			local meta = getmetatable(table)
+			local dbg = debug.getinfo(2, "lS")
+			minetest.log("warning", string.format('Warning: Accessing deprecated "%s" table, "%s" should be used instead (%s:%d).',
+				meta.deprecated, meta.replacement, (dbg.short_src or 'unknown'), (dbg.currentline or 0)))
+			_G[meta.replacement][key]=value
+		end,
+	}
+	rawset(_G, deprecated_global_name, {})
+	setmetatable(_G[deprecated_global_name], meta)
+end
+
+-- deprecated(2) -- December 2018 - Deprecation of font_lib
+deprecated_global_table('font_lib', 'font_api')
diff --git a/init.lua b/init.lua
index 7fbedf9..80fc98a 100644
--- a/init.lua
+++ b/init.lua
@@ -33,6 +33,4 @@ dofile(font_api.path.."/fontform.lua")
 if minetest.get_modpath("display_api") then
 	dofile(font_api.path.."/display_api.lua")
 end
-
--- Compatibility
-font_lib = font_api
+dofile(font_api.path.."/deprecation.lua")