are there any lua bindings for libbullet?
tried using swig and simply %includeing the BulletDynamicsCommon.h:
%module ybullet
%{
#include <btBulletDynamicsCommon.h>
%}
%include "%BULLET_inc_path%/btBulletDynamicsCommon.h"
but that doesn't work, as it also just includes other files, which is ignored by swig:
ybullet/helloWorld.lua:4: attempt to call field 'btDbvtBroadphase' (a nil value)
my lua file is ported from http://bulletphysics.org/mediawiki-1.5.8/index.php/Hello_World
found out a way using swig and a zsh script to automagically extract the %includes from the header files to get this: https://github.com/nonchip/YEngine/blob/master/ybullet/ybullet.i.tpl
Related
I want to parse c source code for extracting variables and functions from it. Is there any library available for this purpose?
I tried to achieve it through query language available in tree-sitter parser generator but when I run the program it says undefined reference to the query functions used in the file even I have included the header file (api.h) containing query functions. I tried to resolve these errors but couldn't so looking for some other library which can serve the purpose.
It's better to do it with Clang (e.g. cindex Python API).
For example, to find all function definitions in a translation unit:
#!/usr/bin/env python3
import sys
import clang.cindex
def find_functions(node):
if node.kind == clang.cindex.CursorKind.FUNCTION_DECL:
nm = node.spelling
print(f"Function {nm}")
else:
for c in node.get_children():
find_functions(c)
index = clang.cindex.Index.create()
tu = index.parse(sys.argv[1])
print('Translation unit:', tu.spelling)
find_functions(tu.cursor)
In my Vim's configuration file init.vim I am using code, that sets a default viewer for practically any kind of file suffix. Here I will demonstrate only an example for .md files:
let g:netrw_browsex_viewer="-"
function! NFH_md(f)
call asyncrun#run("", "cwd", "typora " . a:f)
endfunction
First paragraph makes sure to choose the function based on suffix of the file ("URI under cursor"). Second paragraph shows a function whose name i.e. NFH_md implies that this is the function opened when .md file is in the "URI under the cursor". Inside this function there is an call that opens an external program typora asynchronously so that I am still able to continue using Vim.
If you want to know more use :help netrw_browsex_viewer.
I tried porting the mentioned Vim script to Neovim & Lua but I only managed to port first line:
vim.g.netrw_browsex_viewer="-"
For I don't know, how to properly port the second paragraph. This is why for now I just use Vimscript source code like this:
vim.api.nvim_exec(
[[
function! NFH_md(f)
call asyncrun#run("", "cwd", "marktext " . a:f)
endfunction
]],
false
)
But I would love to translate all the code to Lua - Could anyone help a bit to translate this remaining Vimscript code to Lua?
I'm a neophyte. I know I'm doing something bonheaded. I've search this and other fora for the last day and I'm stuck. I'm trying to use nlohmann's json library. I'm getting over 200 error messages, most of which seem to be rooted in the fact that the compiler can't see the header references in the main json.hpp file, but can see the json.hpp file.
I've copied the nlohmann library contents into the source folder and this is the code at the moment:
#include <iostream>
#include "nlohmann\json.hpp"
using json = nlohmann::json;
int main()
{
std::cout << "Hello World!\n";
}
I'm trying to minimize the number of variables I have to chase.
VS is finding the json.hpp file (no squiggly underline once I finally spelled it right, and a bunch of stuff in solution explorer under json.hpp and nlohmann) It also seems to be seeing the subdirectories of nlohmann
the 'json' after nlohmann:: has a squiggly underline; the popup says: namespace 'nlohmann' has no member 'json'
the first 20 or so 211 (!) error messages are code E1696 'cannot open source file' pointing to apparent references from json.hpp an example is: "E1696 cannot open source file "nlohmann/adl_serializer.hpp" json5 C:\Users\Rich\source\repos\json5\json5\nlohmann\json.hpp"
I've added the 'nlohmann' directory to the include directories that the compiler looks for (Project|properties|C/C++|Additional Include Directories) - no change in error message count. Do I need to manually add all of the subdirectories?
I Think you maybe using an older version of c++ (older than c++11).
Try adding this flag to the command -std=c++11.
I have created a Wireshark dissector in Lua for an application over TCP. I am attempting to use zlib compression and base64 decryption. How do I actually create or call an existing c library in Lua?
The documentation I have seen just says that you can get the libraries and use either the require() call or the luaopen_ call, but not how to actually make the program find and recognize the actual library. All of this is being done in Windows.
You can't load any existing C library, which was not created for Lua, with plain Lua. It's not trivial at least.
*.so/*.dll must follow some specific standard, which is bluntly mentioned in programming in Lua#26.2 and lua-users wiki, code sample. Also similar question answered here.
There are two ways You could solve Your problem:
Writing Your own Lua zlib library wrapper, following those standards.
Taking some already finished solution:
zlib#luapower
lua-zlib
ffi
Bigger list #lua-users wiki
The same applies to base64 encoding/decoding. Only difference, there are already plain-Lua libraries for that. Code samples and couple of links #lua-users wiki.
NOTE: Lua module package managers like LuaRocks or
LuaDist MIGHT save You plenty of time.
Also, simply loading a Lua module usually consists of one line:
local zlib = require("zlib")
The module would be searched in places defined in Your Lua interpreter's luaconf.h file.
For 5.1 it's:
#if defined(_WIN32)
/*
** In Windows, any exclamation mark ('!') in the path is replaced by the
** path of the directory of the executable file of the current process.
*/
#define LUA_LDIR "!\\lua\\"
#define LUA_CDIR "!\\"
#define LUA_PATH_DEFAULT \
".\\?.lua;" LUA_LDIR"?.lua;" LUA_LDIR"?\\init.lua;" \
LUA_CDIR"?.lua;" LUA_CDIR"?\\init.lua"
#define LUA_CPATH_DEFAULT \
".\\?.dll;" LUA_CDIR"?.dll;" LUA_CDIR"loadall.dll"
#else
How do I actually create or call an existing c library in Lua?
An arbitrary library, not written for use by Lua? You generally can't.
A Lua consumable "module" must be linked against the Lua API -- the same version as the host interpreter, such as Lua5.1.dll in the root of the Wireshark directory -- and expose a C-callable function matching the lua_CFunction signature. Lua can load the library and call that function, and it's up to that function to actually expose functionality to Lua using the Lua API.
Your zlib and/or base64 libraries know nothing about Lua. If you had a Lua interpreter with a built-in FFI, or you found a FFI Lua module you could load, you could probably get this to work, but it's really more trouble than it's worth. Writing a Lua module is actually super easy, and you can tailor the interface to be more idiomatic for Lua.
I don't have zlib or a base64 C library handy, so for example's sake lets say we wanted to let our Lua script use the MessageBox function from the user32.dll library in Windows.
#include <windows.h>
#include "lauxlib.h"
static int luaMessageBox (lua_State* L) {
const char* message = luaL_checkstring(L,1);
MessageBox(NULL, message, "", MB_OK);
return 0;
}
int __declspec(dllexport) __cdecl luaopen_messagebox (lua_State* L) {
lua_register(L, "msgbox", luaMessageBox);
return 0;
}
To build this, we need to link against user32.dll (contains MessageBox) and lua5.1.dll (contains the Lua API). You can get Lua5.1.lib from the Wireshark source. Here's using Microsoft's compiler to produce messagebox.dll:
cl /LD /Ilua-5.1.4/src messagebox.c user32.lib lua5.1.lib
Now your Lua scripts can write:
require "messagebox"
msgbox("Hello, World!")
Your only option is to use a library library like alien. See my answer Disabling Desktop Composition using Lua Scripting for other FFI libraries.
I have a DLL that I have ported from VC2008 to C++ Builder XE2. The DLL is used in LabVIEW's TestStand.
TestStand, when importing the VC2008 DLL, can see the function names and their arguments. When using the C++ Builder DLL, all its sees are the function names and not the arguments. All exports are C functions and use extern "C" declspec( dllexport ).
Is there a way to get the exports correct?
I have read that adding a TLB file will do the job, if this is true, how do I create a TLB that exports only C functions?
TestStand can read a .c/.cpp file and derive parameters from that file. You still load the DLL and select the function you want to call. You then 'verify' the parameters and select the .c/.cpp file in the dialog. TestStand will find the function with the same name and insert the parameters itself.
The function must be very specific, I had to create a dummy .c file that contained the prototypes as TestStand could not handle the #defines for dllexport and dllimport. It likes a very specific format. For the function:
TESTAPI bool StartTest( long inNumber ) {}
where TESTAPIis either extern "C" __declspec( dllexport ) or extern "C" __declspec( dllimport I had to write the line below in my dummy file:
bool __declspec( dllexport ) StartTest( long inNumber ) {}
That does it.
DLL function parameters cannot be determined from exports alone, unless they are being decorated by the calling convention (which is unusual to do in a DLL). If a TLB (aka a Type Library) solves the problem, then the VC2008 DLL is likely an In-Process ActiveX/COM object rather than a flat C DLL. If so, then in C+Builder you can use the IDE wizards on the "File | New" menu to create an "ActiveX Library" project, then a "COM Object" to add to the library. Then you will have a TLB that you can define your object with, and the IDE will generate stub code that you can fill in with your object's implementation.
If that is not what LabViews is expecting, then I suggest you contact them and ask. If all it needs is a TLB with flat C functions (which is very unusual, because TLB's are object-oriented), then you can omit the "COM Object" portion and just create an "ActiveX Library" project to get a bare-bones TLB, then add your definitions to it as needed, an then add your exports to the project.
From the reference here:
Avoid using the extern "C" syntax to export symbols. The extern "C" syntax prevents the C/C++ DLL Adapter from obtaining type information for function and method parameters."
A little late to the game, but your problem may be that C++ Builder is decorating the exported function with a leading underscore. The TLIB command line utility should help prove this (assuming tlib still ships with C++Builder)
TLIB mydll.lib, mydll.lst
Look at the resulting lst file and see if it contains StartTest or _StartTest. LabView is probably expecting to find a function without the underscore.
You can add a DEF file to your C++Builder project that will suppress the leading underscore. Try this:
Use the __cdecl calling convention instead of __stdcall.
Export plain "C" functions. No C++ classes or member functions.
Make sure you have an extern "C" {} around your function prototypes.
Create a DEF file that aliases the exported functions to a Microsoft
compatible name. Alias the names so they don't contain a leading
underscore. The DEF file will look like this:
EXPORTS
; MSVC name = C++Builder name
StartTest = _StartTest
Foo = _Foo
Bar = _Bar
5- Add the DEF file to your BCB DLL project and rebuild it.
Check out these ancient articles for more details:
http://bcbjournal.org/articles/vol4/0012/Using_Visual_C_DLLs_with_CBuilder.htm
The reverse article (creating C++Builder DLLs that get called from VC++ created applications) is buried in this archive:
http://www.frasersoft.net/program/bcbdev.zip : /articles/bcbdll.htm. It describes the DEF file trick in more detail, plus some other options.
Note that my answer is based on the way thing were in 1998 or so. They may have changed since then. If they have, then the C++Builder command line tools impdef, tlib, tdump, plus the Microsoft equivalents of those tools, should be able to show you exactly what is in your DLL vs the MSVC one.
H^2
I suggest to use ActiveX object: you can create an automation object in C++Builder and in Labview / TestStand you can import this object. If you use automation, in Lavbiew you will have the correct parameter definition. Make sure you are using a set of compatible type variables with Labview / TestStand.
For example, this fragment of code is the implementation of an array passed from Labview to C++:
STDMETHODIMP TCanLibraryImpl::DataDownload(VARIANT Data, long* RV)
{
_precondition_cmodule();
*RV = 0;
TSafeArrayLong1 mySafeArray(Data.parray);
int dLen =mySafeArray.BoundsLength[0];
...
}
In Labview you will pass to this function an array of I64