src/script.h

   1 /******************************
   2 ** Tsunagari Tile Engine     **
   3 ** script.h                  **
   4 ** Copyright 2011 OmegaSDG   **
   5 ******************************/
   6
   7 #ifndef SCRIPT_H
   8 #define SCRIPT_H
   9
  10 #include <string>
  11
  12 #include <lua.hpp>
  13
  14 class Entity;
  15
  16 //! Compile and execute Lua code at runtime.
  17 /*!
  18         A Script represents a self-contained Lua state. It might have
  19         variables, functions, statements, and expressions, and can be executed.
  20         Each Script lives in a separate memory space and cannot directly
  21         access or call other Scripts.
  22
  23         On their own, Scripts cannot change anything in a game. Instead, you
  24         must bind C functions that they can call. These C functions can access
  25         the C++ objects in the game. You might bind a function that makes a
  26         player jump, or that returns the distance to the nearest town.  You can
  27         also bind variables that a script can access.
  28
  29         Scripts use Lua 5.1
  30 */
  31 class Script
  32 {
  33 public:
  34         //! Create a new Lua state. The state is destroyed with the death of
  35         //this object.
  36         Script();
  37
  38         //! If we already have a Lua state, wrap around it. The state is not
  39         //destroyed with the death of this object.
  40         Script(lua_State* L);
  41
  42         //! Destroy the Lua state if we own it.
  43         ~Script();
  44
  45
  46         //! Bind a C function to a global variable in Lua.
  47         void bindGlobalFn(const char* name, lua_CFunction fn);
  48
  49         //! Bind a C function to a table index. In Lua: "table.index = fn"
  50         void bindObjFn(const char* table, const char* index, lua_CFunction fn);
  51
  52         //! Set a global integer variable in Lua.
  53         void bindInt(const char* name, lua_Integer i);
  54
  55
  56         //! Create a global table with specified name which represents an Entity.
  57         void bindEntity(const char* name, Entity* entity);
  58
  59         //! Get the Entity object from a table in the Lua stack at a specific
  60         //position.
  61         Entity* getEntity(int pos);
  62
  63
  64         //! Compile and run a script, keeping all existing bindings intact.
  65         void run(const char* fn);
  66
  67 private:
  68         //! Did we create our state, or are we borrowing it from another Script
  69         //object?
  70         bool ownState;
  71
  72         //! Everything necessary to compile and run a Lua script.
  73         lua_State* L; // TODO: change to shared_ptr ?
  74 };
  75
  76 #endif
  77