Character Destroy Lua C

The lua source can be found at the lua website here. We'll be using the latest version, 5.2.3 (though other recent versions of Lua will behave similarly).

  1. Character Destroy Lua Ca
  2. Character Destroy Lua Co
  3. Character Destroy Lua Characters

Once you have the latest lua source, it's time to build it. (Yes, you could just download header files and the .dll, but what's the fun in that? When available, it's always better to have the source, that way you can see how things are really working -- and you can debug more easily). Using visual studio:

  • Open up Visual Studio, and create a new project
    • Create a win 32 console application
    • In the Project Creation wizard, check the 'static library' radio button to build as a static library.
  • Add the lua source to the project. Just dragging the files directly from their folders into the project works well for this.
  • There are two source files that you don't need: lua.c and luac.c. These files contain the main program for the command line interpreter and the bytecode compiler, respectively. You can remove this files from the project if you wish. If you are building as a static library, having more than one main won't be a problem. However, if you are building as an executable, then you will need to exclude one of these files from the project. Right-click on them in the project explorer and select 'Exclude from Project'

To compile under Windows (Visual C GUI) do the following: 1: Create a new project. 2: Add the embed.c file. 3: Add the 2 Lua libraries (.lib) - Standard library and the Core library. 4: Add the locations of the Lua include files to the project options ('Directories tab'). 5: You may also have to add the locations of the library files - the. The reason might be that your script is running before the character's appearance has loaded. To do that you add repeat wait until Player.HasAppearanceLoaded. Player.HasAppearanceLoaded returns true or false. You can use the Humanoid:RemoveAccessories function. Or you can use an event called ChildAdded and check if the child is an Accessory. Lua C Table Iteration. The bug is in luanext(L, -2) line, because -2 refers to stack top minus one, which happens here to be the last argument to print. Use luanext(L, i) instead. Upd: Lua stack indexes are subject to float when moving code around at development stage, so the general advice is to. is the number one paste tool since 2002. Pastebin is a website where you can store text online for a set period of time.

You now have a project that you can add to any solution that needs lua. Once you have added the lua project to your game, you need to do a few more steps:

  • In the properties for the project that is using lua, be sure that the directory that contains the lua .h files is included in the set of include paths. If at all possible, make these paths relative, and not absolute
  • Your project will need to get at the .lib files for the lua. There are a few ways to do this:
    • Add a reference from your project to the lua project. Right-click on your project in the project explorer, and select References:
      Add a new reference:
      Select the lua project:
    • Or, add Lua.lib to 'Additional Dependencies' (in the Librarian/Genrerl tab of the Project Property Pages) and add the directory where Lua.lib lives to 'Additional Library Directories' (also in the Librarian/Genrerl tab of the Project Property Pages).

Once we have build Lua, and set up our project dependencies correctly, we are ready to use in on our application,

First off, we need to include the proper header files. Since Lua is ANSI C, if we are coding in C++, we will need to enclose the #includes in extern 'C':

Everything that we need to mantain the current state of the interprer (all global tables, etc) is stored in a variable of type lua_State. The first thing we need to do is create an initial state (essentially, an instantiation of the lua interpreter), which is done by the call:

Every time we want to access the interpreter, we need to pass in this state variable. We can actually have as many instances of Lua state variables as we like (for instance, if we wanted to run separate instances of the interpreter on separate processors, or we wanted different scripts to have different global namespaces), though typically people just use one instance of the interpreter that all scripts use. The global tables in this state variable contain all 'core' functions, but none of the libraries. The libraries contain a bunch of important functions -- including everything in math, and i/o functions like print -- so we'd like to load them. We can load libraries with the call:

So, now we have the skeleton of a main function:

We are ready to start using lua!

We will start with the simplest way to use lua -- have the interpreter execute a file. This is functionally equivalent to the dofile command from within lua (and unsurprisingly, has the same name!). To execute the file 'test.lua', we can use the call:

Note that if we are using relative paths other than absolute paths under windows, then the system will look in the current working directory -- which is the directory that the executable file is in (if you double-click on the executable), or the directory that the project is in (if you run from within Visual Studio) You can, of course, change the working directory that the debugger uses under the project settings in Visual Studio.

So, if we use the following myFile.lua:

when the command luaL_dofile(L, 'myFile.lua') is executed, the following will be printed out

Note that the dofile command not only computes these values and prints them out, it also adds the fib function to the global namespace of our lua enviornment (stored in the C variable L).

We can also call lua functions directly from C/C++, and get back the return values to use in our C/C++ code. To call a lua function we:

  • Push the function on the top of the lua stack, using a call to
    • lua_getGlobal(lua_state *L, char *globalName)
  • Push the arguments to the function on the lua stack, using the functions:
    • lua_pushnumber(lua_state *L, float number)
    • lua_pushstring(lua_state *L, char *str)
    • lua_pushboolean(lua_state *L, bool)
    • lua_pushuserdata(lua_state *L, void *userdata)
    • lua_pushnil(lua_state *L)
  • Call the function, using the function:
    • lua_call(lua_state *L, int numArguments, int numReturnValues)
      We need to pass in both the number of arguments that we are passing in, and the number of arguments that we expect in return. Lua is very loose about the number of arguments and return value, but C/C++ is less so -- hence we need to be explicit when calling lua from C/C++.
  • Extract the return values, using the functions:
    • int lua_tointeger(lua_state *L, int stackLocation)
      Grab an integer value off the lua stack. The first return value is at index -1, the second return value is at index -2, and so on.
    • double lua_tonumber(lua_state *L, int stackLocation)
      Grab a double value off the lua stack. The first return value is at index -1, the second return value is at index -2, and so on.
    • const char *lua_tolstring(lua_state *L, int stackLocation)
      Grab a string value of the lua stack
    • int lua_toboolean(lua_state *L, int stackLocation)
      Grab a boolean value off the lua stack
      Note that these functions 'peek' at the lua stack, they don't actually remove any values from the stack. (That is done by the next function)
  • Pop the return value(s) off the top of the sack (this is just to clean up) with a call to
    • lua_pop(lua_state *L, int numReturnValsToPop);
Let's take a look at how we might call the fib function defined in the previous section to find the 13th Fibonacci number:

Let's look at a second example. Assume that we had defined the following lua function add (that we could define by calling lua_dofile):

We could call this function to add from C/C++ with the code:

So now you could write scripts that you can call from your game engine. However, these scripts won't be very useful if they can't interact with your game objects -- you need a way for your scripts to affect the game world. To do that, you need to be able to call C/C++ functions from lua. Since Lua and C++ have very different conventions for how functions are called, there is a little bit of wrapper work that needs to be done. First, write a C function that takes as input a Lua state variable (the parameters for the function will need to be extracted by hand from the lua stack -- this is slightly tedious, but not too difficult.) Then, the function will need to be registered with lua.

Step 1: Writing a C function that Lua can call

C/C++ functions that are called from lua need to take as an input parameter the lua state. The parameters can be examined on the call stack using the functions lua_tointeger, lua_tonumber, etc (described above). The first parameter is at index 1, the second parameter is at index 2, and so on. Once we have extracted the parameters, we do our calculation, and then push the result on the top of the stack.

Let's look at a slightly more complicated C function. We can write C functions that takes a variable number of parameters, and returns more than one return value. While the previous function assumed that we were passed in two parameters, we can instead query the lua state to see how many parameters were actually passed into the function. The number of parameters is stored on the top of the stack, which can be accessed by a call to lua_gettop(lua_state *L). Let's look at a function that takes in multiple parameters, and calculates the sum and average of all parameters that were passed in:

Step 2: Registering the C function for lua

Once we have written the function, we just need to register it with lua. That is, we need to add the name of the function to the global lua namespace, and provide a pointer to the function so that lua cal access it. There is a helpful macro for this: lua_register(lua_state *L, const char *name, functionPointer fn). So, to register the above two functions:

Step 3: Calling the C funcion from lua

This part is easy -- once the function is registered, lua can call it like any other function.

So, the complete round trip is:

  • Start the lua interpreter
  • Register the C functions you want lua to use
  • Call a lua function from within C, either by a call to luaL_dofile, or by calling a lua function directly
  • The lua function that you called from C can access the C function

We can also send a string straight to the lua interpreter, and it will be executed just as if that string was in a file that was executed with a dofile. So, we could do something like:

and we would get the output:

We could thus create a braindead interpreter as follows:

Note that this would not work at all in a game environment! We will look at how to embed a command-line lua interpreter within a game next time. For now, this is enough for us to play around with a bit.

Now we are ready to get our fingers dirty!

  1. Download the following project, which contains a basic skeleton lua framework
  2. Write a function in C (exposed to Lua, much like average and cAdd) that takes as input an integer n, and returns all prime numbers less than or equal to n.
    • Test your primes function in the interpreter with 'print(primes(100))'
  3. Write a function in lua nthPrime, that takes as input a number n, and returns the nth prime number. So, nthPrime(6) should return 13. We'll define nthPrime(1) to be 2, and nthPrime(0) will be undefined. Your lua function should call the c primes function
    • Small change in how lua does variable numbers of arguments: From the notes

      Alas, this does not work. But we can fix it with a simple change:

  4. Write C code that computes the 100th prime number by calling the lua nthPrime function, and prints the value out using printf. So, C calling Lua that calls C.

I am working on a game project using Corona SDK and I am running into an issue. I am trying to use string.find() in a for loop to test to determine if a value is in a certain table and if so, add that value to another table. My problem is that since string.find()/string.match does not read duplicates in this case (assuming that the for loop is the reason why). I am essentially only having '1102', '1103' instead of '1102', '1102', '1103', '1102', in the 'copy' table which is how I am trying to get this to do. Any suggestions?

Using a nested loop works.

I'm using ipairs, which is similar to for i=1, #list do.

Convolution Neural Network in torch. Error when training the network


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.ccscene files are produced by Corona Composer GUI. Your scene is expecting to load one of these scene files and can't find it. If you're not using the Composer GUI, you probably can ignore this.

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You can use a subprocess to run your Lua script and provide the function with it's arguments. import subprocess result = subprocess.check_output(['lua', '-l', 'demo', '-e', 'test('a', 'b')']) print(result) result = subprocess.check_output(['lua', '-l', 'demo', '-e', 'test2('a')']) print(result) the -l requires the given library (your script) the -e is the code that..

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I have solved this issue with the following code: local ffi = require 'ffi' ffi.cdef[[ typedef struct { char *fpos; void *base; unsigned short handle; short flags; short unget; unsigned long alloc; unsigned short buffincrement; } FILE; FILE *fopen(const char *filename, const char *mode); int fprintf(FILE *stream, const char *format,..

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How do I do user inputs on the same line in Lua?


When called without arguments, reads a whole line. You could read the line and get the words using pattern matching: input = opr, txt = input:match('(%S+)%s+(%S+)') The above code assumes that there is just one word for opr and one word for txt. If there might be zero..

Fast way to initialize a tensor in torch7


See the documentation for the Tensor:apply These functions apply a function to each element of the tensor on which the method is called (self). These methods are much faster than using a for loop in Lua. The example in the docs initializes a 2D array based on its index i..

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Lua C++ Table Iteration


The bug is in lua_next(L, -2) line, because -2 refers to stack top minus one, which happens here to be the last argument to print. Use lua_next(L, i) instead. Upd: Lua stack indexes are subject to float when moving code around at development stage, so the general advice is to..

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Using a nested loop works. for lk, lv in ipairs(list) do for dk, dv in ipairs(database) do if string.find(dv.serial, tostring(lv)) then table.insert(copy, dv.img) end end end I'm using ipairs, which is similar to for i=1, #list do..

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How to iterate through a table in its exact order?


You may utilize integer part of the table to store keys in order: function add(t, k, v, ..) if k ~= nil then t[k] = v t[#t+1] = k return add(t, ..) end return t end t = add({ }, 'A', 'hi', 'B', 'my', 'C', 'name', 'D', 'is') for i,k..

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Because that's what table.concat is documented as doing. Given an array where all elements are strings or numbers, returns table[i].sep.table[i+1] ··· sep.table[j]. The default value for sep is the empty string, the default for i is 1, and the default for j is the length of the table. If i..

Awesome desktop manager widgets


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Lua in pairs with same order as it's written


In Lua, the order that pairs iterates through the keys is unspecified. However you can save the order in which items are added in an array-style table and use ipairs (which has a defined order for iterating keys in an array). To help with that you can create your own..

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Lua obfuscator, how to

Open a command line (e.g. under windows, that's cmd). Go into the directory where you have your local copy of XFuscator. Make sure lua is on your PATH. Type lua XFuscator.lua -h This should show the help message, which will describe the next steps..

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Short answer you can't. But, you can run an URL decode after logrotate. Here is the command : awk -v RS='x[0-9]{2}' 'RT{ORS=sprintf('%c', strtonum('0' substr(RT, 2)))} 1' ..

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ROBLOX Lua Error in script: '=' expected near ''

Character Destroy Lua Ca


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Lua import strings from file


dofile 'user.db' -- try this ..

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