Add StackTracePlus, Rewrite not to recreate eluna on reload

extensions/StackTracePlus/README.md

@@ -0,0 +1,128 @@
+# StackTracePlus #
+
+[![Build Status](https://travis-ci.org/ignacio/StackTracePlus.png?branch=master)](https://travis-ci.org/ignacio/StackTracePlus)
+
+[StackTracePlus](https://github.com/ignacio/StackTracePlus) provides enhanced stack traces for [Lua 5.1, Lua 5.2][1] and [LuaJIT][2].
+
+StackTracePlus can be used as a replacement for debug.traceback. It gives detailed information about locals, tries to guess
+function names when they're not available, etc, so, instead of
+
+    lua5.1.exe: D:\trunk_git\sources\stacktraceplus\test\test.lua:10: attempt to concatenate a nil value
+    stack traceback:
+	D:\trunk_git\sources\stacktraceplus\test\test.lua:10: in function <D:\trunk_git\sources\stacktraceplus\test\test.lua:7>
+	(tail call): ?
+	D:\trunk_git\sources\stacktraceplus\test\test.lua:15: in main chunk
+	[C]: ?
+
+you'll get
+
+    lua5.1.exe: D:\trunk_git\sources\stacktraceplus\test\test.lua:10: attempt to concatenate a nil value
+    Stack Traceback
+    ===============
+    (2)  C function 'function: 00A8F418'
+    (3) Lua function 'g' at file 'D:\trunk_git\sources\stacktraceplus\test\test.lua:10' (best guess)
+	Local variables:
+	 fun = table module
+	 str = string: "hey"
+	 tb = table: 027DCBE0  {dummy:1, blah:true, foo:bar}
+	 (*temporary) = nil
+	 (*temporary) = string: "text"
+	 (*temporary) = string: "attempt to concatenate a nil value"
+    (4) tail call
+    (5) main chunk of file 'D:\trunk_git\sources\stacktraceplus\test\test.lua' at line 15
+    (6)  C function 'function: 002CA480'
+
+## Usage #
+
+StackTracePlus can be used as a replacement for `debug.traceback`, as an `xpcall` error handler or even from C code. Note that
+only the Lua 5.1 interpreter allows the traceback function to be replaced "on the fly". LuaJIT and Lua 5.2 always calls luaL_traceback internally so there is no easy way to override that.
+
+```lua
+local STP = require "StackTracePlus"
+
+debug.traceback = STP.stacktrace
+function test()
+	local s = "this is a string"
+	local n = 42
+	local t = { foo = "bar" }
+	local co = coroutine
+	local cr = coroutine.create
+
+	error("an error")
+end
+test()
+```
+
+That script will output (only with Lua 5.1):
+
+    lua5.1: example.lua:11: an error
+    Stack Traceback
+    ===============
+    (2)  C function 'function: 006B5758'
+    (3) global C function 'error'
+    (4) Lua global 'test' at file 'example.lua:11'
+            Local variables:
+             s = string: "this is a string"
+             n = number: 42
+             t = table: 006E5220  {foo:bar}
+             co = coroutine table
+             cr = C function: 003C7080
+    (5) main chunk of file 'example.lua' at line 14
+    (6)  C function 'function: 00637B30'
+
+**StackTracePlus** is aware of the usual Lua libraries, like *coroutine*, *table*, *string*, *io*, etc and functions like
+*print*, *pcall*, *assert*, and so on.
+
+You can also make STP aware of your own tables and functions by calling *add_known_function* and *add_known_table*.
+
+```lua
+local STP = require "StackTracePlus"
+
+debug.traceback = STP.stacktrace
+local my_table = {
+	f = function() end
+}
+function my_function()
+end
+
+function test(data, func)
+	local s = "this is a string"
+
+	error("an error")
+end
+
+STP.add_known_table(my_table, "A description for my_table")
+STP.add_known_function(my_function, "A description for my_function")
+
+test( my_table, my_function )
+```
+
+Will output:
+
+    lua5.1: ..\test\example2.lua:13: an error
+    Stack Traceback
+    ===============
+    (2)  C function 'function: 0073AAA8'
+    (3) global C function 'error'
+    (4) Lua global 'test' at file '..\test\example2.lua:13'
+            Local variables:
+             data = A description for my_table
+             func = Lua function 'A description for my_function' (defined at line 7 of chunk ..\test\example2.lua)
+             s = string: "this is a string"
+    (5) main chunk of file '..\test\example2.lua' at line 19
+    (6)  C function 'function: 00317B30'
+
+
+## Installation #
+The easiest way to install is with [LuaRocks][3].
+
+  - luarocks install stacktraceplus
+
+If you don't want to use LuaRocks, just copy StackTracePlus.lua to Lua's path.
+
+## License #
+**StackTracePlus** is available under the MIT license.
+
+[1]: http://www.lua.org/
+[2]: http://luajit.org/
+[3]: http://luarocks.org/