WoW:API loadstring: Difference between revisions

242 bytes removed ,  23 September 2007
yank divs, fix headers
(And that's how you document functions =))
 
(yank divs, fix headers)
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== Examples ==
== Examples ==


=== Emulating [[API RunScript|RunScript]] === <div style="margin-left: 3%;">
=== Emulating RunScript() ===


  [[API assert|assert]](loadstring("DEFAULT_CHAT_FRAME:AddMessage(\"Hello, World!\")")) ();
  assert(loadstring("DEFAULT_CHAT_FRAME:AddMessage(\"Hello, World!\")")) ();


If an error occurs, the assert will trigger and automatically display the errorMessage return since assert()s second parameter is the error message to display. If it is successful, the function reference returned will also be returned out through the assert() call, and then be executed directly by the "()".
If an error occurs, the assert will trigger and automatically display the errorMessage return since assert()s second parameter is the error message to display. If it is successful, the function reference returned will also be returned out through the assert() call, and then be executed directly by the "()".




</div>
=== Catching all errors ===  
=== Catching all errors === <div style="margin-left: 3%;">
  local func, errorMessage = loadstring("DEFAULT_CHAT_FRAME:AddMessage(\"Hello, World!\")");
  local func, errorMessage = loadstring("DEFAULT_CHAT_FRAME:AddMessage(\"Hello, World!\")");
  if(not func) then
  if(not func) then
   ''... do something with errorMessage and return out?''
   ''... do something with errorMessage and return out?''
  end
  end
  local success, errorMessage = [[API pcall|pcall]](func);
  local success, errorMessage = pcall(func);
  if(not success) then
  if(not success) then
   ''... do something with errorMessage and return out?''
   ''... do something with errorMessage and return out?''
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</div>
=== Returning values ===
=== Returning values === <div style="margin-left: 3%;">
Since the code block is actually a function, you can return values out of it just like with a function. ''(ignoring error handling for now)''
Since the code block is actually a function, you can return values out of it just like with a function. ''(ignoring error handling for now)''
   local func = assert(loadstring("return 38+4, \"Hello, World!\";"));
   local func = assert(loadstring("return 38+4, \"Hello, World!\";"));
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</div>
=== Protecting the global environment ===
=== Protecting the global environment === <div style="margin-left: 3%;">


Lua can manipulate the environment that a function gets to see with [[API setfenv|setfenv]](). It is however important to remember that already-existing functions that the code is allowed to call retain their original environments, so e.g. giving protected code access to the standard [[API setglobal|setglobal]]() is probably not a good idea.
Lua can manipulate the environment that a function gets to see with [[API setfenv|setfenv]](). It is however important to remember that already-existing functions that the code is allowed to call retain their original environments, so e.g. giving protected code access to the standard [[API setglobal|setglobal]]() is probably not a good idea.
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</div>
=== Creating "real" functions through loadstring ===
 
=== Creating "real" functions through loadstring === <div style="margin-left: 3%;">
 
  local func = assert(loadstring([[
  local func = assert(loadstring([[
   return function(a,b)
   return function(a,b)
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Will result in "meaning_of_life_the_universe_and_everything" containing the number 42.
Will result in "meaning_of_life_the_universe_and_everything" containing the number 42.


</div>
{{LUA}}
{{LUA}}