Lua: Difference between revisions

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{{Software

|name = Lua

|image = Lua-Logo.svg.png

|type = Library

|authors = Roberto Ierusalimschy

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Lua originated in 1993 as a language for extending software applications to meet the increasing demand for customization at the time. It provided the basic facilities of most procedural programming languages, but more complicated or domain-specific features were not included; rather, it included mechanisms for extending the language, allowing programmers to implement such features. As Lua was intended to be a general embeddable extension language, the designers of Lua focused on improving its speed, portability, extensibility and ease-of-use in development.

== WoW Lua

== WoW Lua ==

By the release of 3.3.5a, Blizzard had made various helpful modifications to its version of Lua.

=== Taint

=== Taint ===

In WoW Lua, each variable contains a taint value, a string that identifies the AddOn from where the variable originated.

=== Profiling ===

Because each variable is taint-tagged by whichever AddOn generated it, WoW Lua is able to compute the memory usage of any particular AddOn.

<pre>

void lua_gcupdatesizes(lua_State* L);

lu_mem lua_gcgetsize(lua_State* L, const char* tag);

</pre>

Optionally, function performance can be profiled by turning on a flag (which is governed by the <code>scriptProfile</code> CVar).

You can read the results of the function profiler with:

<pre>

void lua_gcupdatetimes(lua_State* L);

lua_Number lua_gcgettime(lua_State* L, const char* tag);

void lua_gcgetfunctiontime(lua_State* L, lua_Number* flat, lua_Number* total, int32_t* ncalls);

void lua_gcresettimes(lua_State* L);

</pre>

=== Standard library ===

WoW Lua modifies the standard library by removing functions that expose the host filesystem, modifying existing functions, or adding new ones.

These functions were removed from the standard library:

* <code>dofile()</code>, <code>loadfile()</code> - Removed to prevent Lua from touching the host filesystem.

* <code>load()</code> - Reason for removal unclear

* <code>print()</code> - Removed to prevent Lua from touching stdout. This is replaced by a function that prints output to the ingame chat.

* <code>math.randomseed()</code>

* <code>string.sub()</code>

These existing standard library functions were modified:

* <code>getfenv()</code> - Implementation adds this code to end of function: <code>luaL_getmetafield(L, -1, "__environment");</code>

* <code>string.upper()</code>, <code>string.lower()</code> - These were modified to support UTF-8 strings. Unlike stock Lua, they are able to convert special characters including Latin-1 and Cyrillic.

These standard library functions were added by Blizzard:

* <code>table.removemulti()</code>

* <code>table.wipe()</code>

@@ Line 2: / Line 2: @@
 {{Software
   |name        = Lua
+ |image       = Lua-Logo.svg.png
   |type        = Library
   |authors     = Roberto Ierusalimschy
@@ Line 19: / Line 20: @@
 Lua originated in 1993 as a language for extending software applications to meet the increasing demand for customization at the time. It provided the basic facilities of most procedural programming languages, but more complicated or domain-specific features were not included; rather, it included mechanisms for extending the language, allowing programmers to implement such features. As Lua was intended to be a general embeddable extension language, the designers of Lua focused on improving its speed, portability, extensibility and ease-of-use in development.
-== WoW Lua
+== WoW Lua ==
 By the release of 3.3.5a, Blizzard had made various helpful modifications to its version of Lua.
-=== Taint
+=== Taint ===
 In WoW Lua, each variable contains a taint value, a string that identifies the AddOn from where the variable originated.
+=== Profiling ===
+Because each variable is taint-tagged by whichever AddOn generated it, WoW Lua is able to compute the memory usage of any particular AddOn.
+<pre>
+void   lua_gcupdatesizes(lua_State* L);
+lu_mem lua_gcgetsize(lua_State* L, const char* tag);
+</pre>
+Optionally, function performance can be profiled by turning on a flag (which is governed by the <code>scriptProfile</code> CVar).
+You can read the results of the function profiler with:
+<pre>
+void       lua_gcupdatetimes(lua_State* L);
+lua_Number lua_gcgettime(lua_State* L, const char* tag);
+void       lua_gcgetfunctiontime(lua_State* L, lua_Number* flat, lua_Number* total, int32_t* ncalls);
+void       lua_gcresettimes(lua_State* L);
+</pre>
+=== Standard library ===
+WoW Lua modifies the standard library by removing functions that expose the host filesystem, modifying existing functions, or adding new ones.
+These functions were removed from the standard library:
+* <code>dofile()</code>, <code>loadfile()</code> - Removed to prevent Lua from touching the host filesystem.
+* <code>load()</code> - Reason for removal unclear
+* <code>print()</code> - Removed to prevent Lua from touching stdout. This is replaced by a function that prints output to the ingame chat.
+* <code>math.randomseed()</code>
+* <code>string.sub()</code>
+These existing standard library functions were modified:
+* <code>getfenv()</code> - Implementation adds this code to end of function: <code>luaL_getmetafield(L, -1, "__environment");</code>
+* <code>string.upper()</code>, <code>string.lower()</code> - These were modified to support UTF-8 strings. Unlike stock Lua, they are able to convert special characters including Latin-1 and Cyrillic.
+These standard library functions were added by Blizzard:
+* <code>table.removemulti()</code>
+* <code>table.wipe()</code>