Lua State Wrapper

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Cower	Created : 31 January 2010 System : Cross Platform Language : Blitz Max Lua State Wrapper Object-oriented wrapper around Lua states
This is a fairly simple OO wrapper around the Lua API (not including the debugging API, and most of the auxiliary API is ignored). In most situations, names are the same or similar to the equivalent lua_* function. There are Load* methods provided that will load a string, buffer, or URL as a function. No complementary Do(...) methods are provided, as you can simply call Load(...).Call() through the hacked method chaining (by returning Self for most methods). SuperStrict Import Pub.Lua Private Function _lsb@ Ptr(s@ Ptr, d@ Ptr, sz:Int Ptr) Const _LBUF_READ:Int=1024 Local bufP:Byte Ptr Ptr = Byte Ptr Ptr(d+4) Local remainderP:Int Ptr = Int Ptr(d) If remainderP[0] = 0 Then sz[0] = 0 Return Null EndIf Local p@ Ptr = bufP[0] sz[0] = Min(remainderP[0],_LBUF_READ) remainderP[0] :- sz[0] bufP[0] :+ sz[0] Return p End Function Function _ls_alloc@ Ptr(ud@ Ptr, p@ Ptr, osize:Int, nsize:Int) If nsize = 0 Then MemFree(p) Return NULL ElseIf p Then Return MemExtend(p, osize, nsize) Else Return MemAlloc(nsize) EndIf End Function Public Rem bbdoc: A class for interfacing with Lua in an object-oriented manner. EndRem Type Lua Field _disposable:Int = False Field _state@ Ptr = Null Method Delete() Dispose() End Method Rem bbdoc: Forces the disposal of the class and/or Lua state (depending on the settings specified on creation). EndRem Method Dispose:Lua() If _disposable = True And _state <> Null Then lua_close(_state) EndIf _state = Null Return Self End Method Method InitWithState:Lua(L@Ptr, canFree:Int = False) _state = L _disposable = canFree=True Return Self End Method Method Init:Lua() Return InitWithState(lua_newstate(_ls_alloc, Null), True) End Method Method IsValid:Int() Return (_state<>Null) End Method Rem bbdoc: Creates a new Lua from an existing Lua state.<br/> <br/> If you pass True to @canFree, the state will be freed when the class is disposed of (either on garbage collection or when the @Dispose method is called).<br/> <br/> When extending this class, you should override this function so that it creates the extended class. That, or you can just do <pre>New YourExtendedClass.InitWithState(state, True/False)</pre>, provided you override InitWithState. EndRem Function FromState:Lua(s@ Ptr, canFree:Int = False) Return New Lua.InitWithState(s, canFree) End Function Rem bbdoc: Creates a new Lua class and Lua state. View @FromState for extra advice regarding implementation. EndRem Function Create:Lua() Return New Lua.Init() End Function Rem bbdoc: Loads the lualib libraries. EndRem Method LoadLibraries:Lua() luaopen_base(_state) luaopen_package(_state) luaopen_string(_state) luaopen_math(_state) luaopen_table(_state) luaopen_io(_state) luaopen_os(_state) luaopen_debug(_state) Return Self End Method Method LoadBaseLibrary:Lua() luaopen_base(_state) Return Self End Method Method LoadPackageLibrary:Lua() luaopen_package(_state) Return Self End Method Method LoadStringLibrary:Lua() luaopen_string(_state) Return Self End Method Method LoadMathLibrary:Lua() luaopen_math(_state) Return Self End Method Method LoadTableLibrary:Lua() luaopen_table(_state) Return Self End Method Method LoadIOLibrary:Lua() luaopen_io(_state) Return Self End Method Method LoadOSLibrary:Lua() luaopen_os(_state) Return Self End Method Method LoadDebugLibrary:Lua() luaopen_debug(_state) Return Self End Method Method LoadBuffer:Lua(buf@ Ptr, length:Int, name$=Null) Global _lua_load:Int(L@Ptr,R@Ptr(L@Ptr,O@Ptr,S:Int Ptr),O@Ptr,N@Ptr) = Byte Ptr(lua_load) Local mem:Int Ptr = Int Ptr(MemAlloc(8)) mem[0] = length mem[1] = Int(buf) Local nstr@ Ptr = Null If name Then nstr = name.ToCString() Local r:Int = _lua_load(_state, _lsb, mem, nstr) MemFree(mem) If nstr Then MemFree(nstr) Local err$ If r <> 0 Then err = GetString() Pop 1 EndIf Select r Case 0 ' success Case 1 Throw "Runtime error during lua_load:~n"+err Case 2 Throw "File error during lua_load:~n"+err Case 3 Throw "Syntax error during lua_load:~n"+err Default Throw "Error during lua_load:~n"+err End Select Return Self End Method Rem bbdoc: Loads a string as a function and pushes it onto the stack. EndRem Method LoadString:Lua(s$, name$=Null) Local str@ Ptr = s.ToCString() Try LoadBuffer(str, s.Length, name) Catch ex:Object MemFree(str) Throw ex End Try MemFree(str) Return Self End Method Rem bbdoc: Loads the contents of a stream or a string as a function and pushes it onto the stack. EndRem Method LoadURL:Lua(url:Object, length:Int=-1, name$=Null) Local s:TStream = OpenStream(url, True, False) If s = Null Throw "Could not open stream for reading" EndIf If length = -1 Then length = s.Size() Local buf@ Ptr = MemAlloc(length) s.ReadBytes(buf, length) s.Close(); s = Null Try LoadBuffer(buf, length, name) Catch ex:Object MemFree(buf) Throw ex End Try MemFree(buf) Return Self End Method Rem bbdoc: Registers a callback so it's accessible to Lua scripts. EndRem Method RegisterFunction:Lua(name$, func:Int(state@ Ptr), upvalues:Int=0) lua_pushlstring(_state, name, name.Length) lua_pushcclosure(_state, func, upvalues) lua_rawset(_state, LUA_GLOBALSINDEX) Return Self End Method Rem bbdoc: Pops @n elements from the stack. EndRem Method Pop:Lua(n:Int = 1) lua_settop(_state, -(n+1)) Return Self End Method Rem bbdoc: Gets a value from a table.<br/> <br/> To use this, you have to push the key (be it a number or string or what have you) and call this with the correct index of the table. The key will be popped and the resulting value will be pushed onto the stack. EndRem Method GetTable:Lua(idx:Int) lua_gettable(_state, idx) Return Self End Method Rem bbdoc: Gets a value from a table.<br/> <br/> To use this, you have to push the key (be it a number or string or what have you) and value, then call this with the correct index of the table. The key and value will be popped from the stack, no cleanup is neccessary. EndRem Method SetTable:Lua(idx:Int) lua_settable(_state, idx) Return Self End Method Method RawGet:Lua(idx:Int) lua_rawget(_state, idx) Return Self End Method Method RawSet:Lua(idx:Int) lua_rawset(_state, idx) Return Self End Method Method RawGetWithIndex:Lua(idx:Int, n%) lua_rawgeti(_state, idx, n) Return Self End Method Method RawSetWithIndex:Lua(idx:Int, n%) lua_rawseti(_state, idx, n) Return Self End Method Method GetNext:Int(idx:Int) Return lua_next(_state, idx) End Method Rem bbdoc: Creates a table and pushes it onto the stack. EndRem Method CreateTable:Lua(narr:Int=0, nrec:Int=0) lua_createtable(_state, narr, nrec) Return Self End Method Rem bbdoc: Creates a new userdata with the specified @size, pushes it onto the stack, and returns a pointer to the userdata. EndRem Method CreateUserdata@ Ptr(size:Int) Return lua_newuserdata(_state, size) End Method Rem bbdoc: Creates a new thread, pushes it onto the stack, and returns a new Lua state for the new thread. EndRem Method CreateThread:Lua() Local L@Ptr = lua_newthread(_state) Return New Lua.InitWithState(L, False) End Method Method PushThread:Lua(thread:Lua) lua_pushthread(thread._state) Return Self End Method Rem bbdoc: Pushes a string onto the stack. EndRem Method PushString:Lua(s$) lua_pushlstring(_state, s, s.Length) Return Self End Method Rem bbdoc: Pushes a boolean value onto the stack. True or False only. EndRem Method PushBool:Lua(b:Int) lua_pushboolean(_state, b) Return Self End Method Rem bbdoc: Pushes a number onto the stack. EndRem Method PushNumber:Lua(n!) lua_pushnumber(_state, n) Return Self End Method Rem bbdoc: Pushes an integer onto the stack. EndRem Method PushInteger:Lua(n%) lua_pushinteger(_state, n) Return Self End Method Rem bbdoc: Pushes a nil (Null) value onto the stack. This is <em>not</em> the same as pushing a Null pointer onto the stack. EndRem Method PushNil:Lua() lua_pushnil(_state) Return Self End Method Rem bbdoc: Pushes a pointer (light userdata) onto the stack. EndRem Method PushLightUserdata:Lua(p@ Ptr) lua_pushlightuserdata(_state, p) Return Self End Method Rem bbdoc: Pushes a C closure onto the stack. EndRem Method PushCClosure:Lua(fn:Int(L@Ptr), upvalues:Int=0) lua_pushcclosure(_state, fn, upvalues) Return Self End Method Rem bbdoc: Pushes the value at @idx onto the top of the stack. EndRem Method PushValue:Lua(idx:Int) lua_pushvalue(_state, idx) Return Self End Method Rem bbdoc: Inserts the value at the top of the stack to the stack position @idx. EndRem Method InsertValue:Lua(idx:Int) lua_insert(_state, idx) Return Self End Method Method RemoveValue:Lua(idx:Int) lua_remove(_state, idx) Return Self End Method Method ReplaceValue:Lua(idx:Int) lua_replace(_state, idx) Return Self End Method Rem bbdoc: Gets a string from @idx. EndRem Method GetString$(idx:Int = -1) Return String.FromCString(lua_tolstring(_state, idx, Null)) End Method Rem bbdoc: Gets a boolean from @idx. EndRem Method GetBool:Int(idx:Int = -1) Return lua_toboolean(_state, idx) End Method Rem bbdoc: Gets a number from @idx. EndRem Method GetNumber!(idx:Int = -1) Return lua_tonumber(_state, idx) End Method Rem bbdoc: Gets an integer from @idx. EndRem Method GetInteger:Int(idx:Int = -1) Return lua_tointeger(_state, idx) End Method Method GetFunction%(L@Ptr)(idx%) Return lua_tocfunction(_state, idx) End Method Rem bbdoc: Gets a pointer (light userdata) from @idx. EndRem Method GetUserdata@ Ptr(idx:Int = -1) Return lua_touserdata(_state, idx) End Method Rem bbdoc: Gets a thread from @idx. EndRem Method GetThread:Lua(idx:Int = -1) Return New Lua.InitWithState(lua_tothread(_state, idx), False) End Method Rem bbdoc: Concatenates @n values at the top of the stack and pushes the result. EndRem Method Concatenate:Lua(n:Int) lua_concat(_state, n) Return Self End Method Rem bbdoc: Performs 'left < right' where left and right are the values at the indices provided by @left and @right. Returns true if the left value is smaller than the right value, otherwise false. EndRem Method LessThan:Int(left:Int, right:Int) Return lua_lessthan(_state, left, right) End Method Rem bbdoc: Performs 'left == right' where left and right are the values at the indices provided by @left and @right. Returns true if the left value is smaller than the right value, otherwise false. EndRem Method Equal:Int(left:Int, right:Int) Return lua_equal(_state, left, right) End Method Method RawEqual:Int(left:Int, right:Int) Return lua_rawequal(_state, left, right) End Method Method Length:Int(idx%=-1) Return lua_objlen(_state, idx) End Method Rem bbdoc: Generates a Lua error whose message is the value at the top of the stack.<br/><br/> This function never returns. EndRem Method Error:Lua() lua_error(_state) Return Self End Method Rem bbdoc: Generates a Lua error with the specified @message.<br/><br/> This function never returns. EndRem Method ErrorWithMessage:Lua(message$) PushString(message) lua_error(_state) Return Self End Method Rem bbdoc: Generates a Lua error with the specified @message (if provided) if @cond is true.<br/> <br/> This function never returns. EndRem Method ErrorIf:Lua(cond:Int, message$="") If cond Then PushString(message) Error EndIf Return Self End Method Rem bbdoc: Returns the type of value at @idx.<br/> <br/> This can be any of the following values:<br/> <ul> <li>LUA_TNONE</li> <li>LUA_TNIL</li> <li>LUA_TBOOLEAN</li> <li>LUA_TNUMBER</li> <li>LUA_TSTRING</li> <li>LUA_TUSERDATA</li> <li>LUA_TLIGHTUSERDATA</li> <li>LUA_TTABLE</li> <li>LUA_TFUNCTION</li> <li>LUA_TTHREAD</li> <li>LUA_TNONE</li> </ul> EndRem Method GetType:Int(idx:Int = -1) Return lua_type(_state, idx) End Method Method GetTypename$(idx:Int = -1) Return lua_typename(_state, idx) End Method Rem bbdoc: Returns whether or not the value at @idx is of the specified type (or can be converted to that type).<br/><br/> ORed combinations of types work, but will not check whether or not the value at @idx can be converted to the specified types. EndRem Method Is:Int(idx:Int, klass:Int) Select klass Case LUA_TTABLE Return lua_istable(_state, idx) Case LUA_TSTRING Return lua_isstring(_state, idx) Case LUA_TUSERDATA Return lua_isuserdata(_state, idx) Case LUA_TLIGHTUSERDATA Return lua_islightuserdata(_state, idx) Case LUA_TNUMBER Return lua_isnumber(_state, idx) Case LUA_TNIL Return lua_isnil(_state, idx) Case LUA_TNONE Return lua_isnone(_state, idx) Case LUA_TNIL\|LUA_TNONE Return lua_isnoneornil(_state, idx) Case LUA_TTHREAD Return lua_isthread(_state, idx) Case LUA_TFUNCTION Return lua_isfunction(_state, idx) Case LUA_TBOOLEAN Return lua_isboolean(_state, idx) Default Return (klass&lua_type(_state, idx)) End Select End Method Method IsNumber:Int(idx%) Return lua_isnumber(_state, idx) End Method Method IsBoolean:Int(idx%) Return lua_isboolean(_state, idx) End Method Method IsString:Int(idx%) Return lua_isstring(_state, idx) End Method Method IsCFunction:Int(idx%) Return lua_iscfunction(_state, idx) End Method Method IsFunction:Int(idx%) Return lua_isfunction(_state, idx) End Method Method IsTable:Int(idx%) Return lua_istable(_state, idx) End Method Method IsUserdata:Int(idx%) Return lua_isuserdata(_state, idx) End Method Method IsLightUserdata:Int(idx%) Return lua_islightuserdata(_state, idx) End Method Method IsNil:Int(idx%) Return lua_isnil(_state, idx) End Method Method IsNone:Int(idx%) Return lua_isnone(_state, idx) End Method Method IsNoneOrNil:Int(idx%) Return lua_isnoneornil(_state, idx) End Method Method IsThread:Int(idx%) Return lua_isthread(_state, idx) End Method Rem bbdoc: Returns the lua_State pointer. Endrem Method State@ Ptr() Return _state End Method Method Call:Lua(args:Int=0, results:Int=0, protected:Int=True) If Not protected Then lua_call(_state, args, results) Return Self EndIf Local r:Int = lua_pcall(_state, args, results, 0) Local err$ If r <> 0 Then err = GetString() Pop 1 EndIf Select r Case 0 Case 1 Throw "Runtime error encountered during lua_pcall:~n"+err Case 4 Throw "Memory allocation error encountered during lua_pcall:~n"+err Case 5 Throw "Error calling the error handler function during lua_pcall:~n"+err Default Throw "Error during lua_pcall:~n"+err End Select Return Self End Method Method GetField:Lua(idx:Int, name$) lua_getfield(_state, idx, name) Return Self End Method Method SetField:Lua(idx:Int, name$) lua_setfield(_state, idx, name) Return Self End Method Method GetGlobal:Lua(name$) lua_getfield(_state, LUA_GLOBALSINDEX, name) Return Self End Method Method SetGlobal:Lua(name$) lua_setfield(_state, LUA_GLOBALSINDEX, name) Return Self End Method Method GetEnvironment:Lua(idx:Int) lua_getfenv(_state, idx) Return Self End Method Method SetEnvironment:Lua(idx:Int) lua_setfenv(_state, idx) Return Self End Method Method GetMetatable:Lua(idx:Int) lua_getmetatable(_state, idx) Return Self End Method Method SetMetatable:Lua(idx:Int) lua_setmetatable(_state, idx) Return Self End Method Method Resume:Int(nargs:Int) Return lua_resume(_state, nargs) End Method Method Yield:Int(results:Int) Return lua_yield(_state, results) End Method Method Status:Int() Return lua_status(_state) End Method Method ExchangeValues:Lua(with:Lua, n:Int) lua_xmove(_state, with._state, n) Return Self End Method Rem bbdoc: Returns the size of the stack. EndRem Method GetTop:Int() Return lua_gettop(_State) End Method Method SetTop:Lua(top:Int) lua_settop(_state, top) Return Self End Method Method CheckStack:Int(extra:Int) Return lua_checkstack(_state, extra) End Method End Type --v

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