So I am writing and testing my new OS kernel and just finished the part where it loads up /bin/init.lua, I tested it, it loads up init.lua, andddd it exit mid-execution. I have a function in init.lua where it prints out test message, but it need to access two specific function from the kernel but it cannot seem to access it. Any idea how to make a code executed by load()() be able to access functions from its caller?
Just in case you need to see the source code: https://github.com/WattanaGaming/OCLinux/blob/master/boot/kernel/OCLinux.lua#L86
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I was just wondering in roblox if anyone has ever come upon a situation where they needed to run scripts from another script. My situation is that I am making a control point system for a game. I need to be able to know if the other points are captured in order to capture the next ones so I am attempting to write a controller on top of it but i am not sure exactly how to access the functions from within the control point script.
Yes! ROBLOX provides a very useful feature called ModuleScripts for the very purpose of calling scripts from other scripts. The icon for ModuleScripts looks the same as the icon for regular Scripts except with a little brick in the bottom-right.
The way it works is that regular Scripts can call ModuleScripts in the game using the special require() function. The easiest way to explain this is with an example.
To begin, let's imagine that we have a Script and a ModuleScript. The Script will be located at game.Workspace.normalScript, and the ModuleScript will be located inside a brick called part at game.Workspace.part.moduleScript.
moduleScript will contain the following code:
script.Parent.Transparency = .5 --"Parent" is the part since this ModuleScript is located inside the part
Now, normalScript will contain the following code:
require(game.Workspace.part.moduleScript)
When you run the game, normalScript will execute moduleScript, changing the transparency of part to .5. When one calls require() on a ModuleScript, it will act as though it were a normal function being called. moduleScript acted as though it were a function, and ModuleScripts in general act the same way as functions for the most part.
This also means that ModuleScripts can return values like functions. For example, if we have the following code in moduleScript:
return 3+3
Now, our script will contain the following code:
local number = require(game.Workspace.moduleScript)
print(number) --> 6
This code will print "6" to the console since moduleScript returned 6. As you might guess, this means that ModuleScripts have many more uses than simply remotely executing code.
Here are two more examples of uses of ModuleScripts:
1) Returning functions:
moduleScript:
return function()
print("hey")
end
normalScript:
local func = require(game.Workspace.moduleScript)
func() --> hey
2) Returning modules such as apple below:
moduleScript:
local apple = {}
apple.flavor = "sweet"
return apple
normalScript:
local fruit = require(game.Workspace.moduleScript)
print(fruit.flavor) --> sweet
These are rather silly examples of ModuleScript uses, but ModuleScripts can actually be very powerful tools. For some cool examples, visit the ROBLOX Wiki page on ModuleScripts and scroll about halfway down.
I am trying to work on whats wrong with my lithium current setup. I have installed the Xdebug and verified that remote host can establish the connection as requested.
http://myinstance.com/test/lithium/tests/cases/analysis/logger/adapter/CacheTest?filters[]=lithium\test\filter\Coverage
Please note in fresh installation in local environment , "Coverage" Filter is working as expected.
I added some test code inside the "apply" function in coverage.php but it is not even called !!!! Can some have experience in debugging the above URL ?
I am not able to understand why coverage filter is not called up and executed ...Any hints are highly appreciated !
The filters in the query string are added to the options in lithium\test\Controller::__invoke() and then passed into the test Report object created by the test Dispatcher. The Report object finds the test filter class and then runs the applyFilter() method for that test filter as can be seen in lines 140 to 143 of the current code. So those lines would be another place to debug. Those should wrap the run() method of your tests with this filter code inside the apply() method that uses xdebug_get_code_coverage() and related functions. You said you added test code in the apply method and it isn't called. I'm not sure what the issue is. Are you sure you are pointing to the right server and code location? It is possible to run tests from the command line. Maybe you should try that. See code comments in lithium\console\command\Test or run li3 test --help for info on how to use the command-line test runner.
I can confirm on nginx I also have /test/lithium/tests/cases/analysis/logger/adapter/CacheTest?filters[]=lithium\x5Ctest\x5Cfilter\x5CCoverage in my access log. The \x5C is expected url encoding of the backslash character.
I have an application that periodically will run a Lua script. Within the script, on occasion, I have created a custom registered Lua function to check some parameters and decide if the Lua script should continue or exit. The logic ideally should not be part of the script and I can think of using a Lua script to work around this, but I'm wondering if it is possible to stop the execution of a Lua script without ending the application.
I have a custom function written in Delphi and exposed to Lua scripts using Lua 5.1. The Lua script looks something like that shown below and the script in Lua is started using luaL_loadbuffer.
io.write("Script starting\n");
--Custom Function
ExitIfFound();
io.write("Script continuing\n");
My custom function looks something like this, below I have provided one of my attempts where I tried to use lua_error to stop the script...
function ExitIfFound(LuaState: TLuaState): Integer;
var
s: AnsiString;
begin
s := 'ExitIfFound ending script, next Lua script line not called';
lua_pushstring(LuaState, PAnsiString(s));
lua_error(LuaState);
end;
When my custom function is called, I'm unsure as to how to exit the Lua script without any further evaluation. I have seen posts referring to Lua and using setjmp and longjmp in C, but I'm curious how these may translate Delphi.
In the example above, when I use lua_error, the entire program crashes with Windows doing its typical, [luarun.exe has stopped working] ...
With all of this, I'm am still pretty new to integrating Lua to Delphi and hoping that I can find some cleaner options to explore.
There is no clean way to entirely abort a Lua script. The lua_error function is the correct way to signal an error. It is the caller's responsibility to catch the error and propagate it to the next caller.
If you cannot rely on the caller to cooperate, then you can try to exert more control by installing debug hooks. Then the host program will be consulted before continuing to run the script. However, the script can still avoid exiting by using pcall to catch any errors.
The crash in your program is probably not simply from setting an error. Rather, it's likely from using the wrong calling convention on your ExitIfFound function. It needs to be cdecl, but Delphi's default, if you don't specify anything else, is register. Using the wrong calling convention will give you unpredictable parameter values and can lead to a corrupted stack. If you type-casted the function or used the # operator when you called lua_register, then you might have hidden the calling-convention mismatch from the compiler's type checker, which would have otherwise alerted you to the problem at compile time.
When compiled as C++, lua_error will use a exception instead of longjmp, but either way, the caller always catches the error. Exceptions are important, though, when your Delphi code uses compiler-managed types like string, or exception-sensitive constructs like try-finally blocks. In C mode, lua_error calls longjmp to jump directly to the waypoint set by a previous call to setjmp. That jump will skip over any exception handlers like the ones the Delphi compiler sets up to ensure the finally block runs and the string gets cleaned up.
A further headache is that since the compiler cleans up the string while exiting the function, the pointer you put on the Lua stack might not be valid by the time it's used; that depends on whether lua_pushstring makes a copy of its argument.
I just want to call some specific function in my Lua script.
A simple script:
msg("hello")
function showamsgbox()
msg("123")
end
I just want to let my C app call showamsgbox() only but not to run msg("hello") beacuse it will show a msgbox when i load this script! So how to do that to keep this situation away?
PS:it is just example.sometimes i want to let users make thier own plugins in my program.but I do not want them write something outside the functions(i want to use functions to decide what to do.for example function OnLoad() means it will be run when i load it ).If there is something outside functions i cannot control them!
You can't. The script defines two variables when run: a and geta. Recall that function geta()...end is the same as geta=function()...end.
The a = 9 will be called when the script is initially evaluated in a lua_State.
If you reuse that lua_State instance, you can retrieve the function and invoke it without re-initializing a.
It seems that you want to sandbox scripts. Just give them a suitable, separate environment before running them. It may be an empty one or it may contain references to the functions you want them to use. They can write at will in their environment and it will not affect yours. Then just get the value of OnLoad or whatever user function you want to call and call it.
I'm writing a GUI that's meant to be easily customizable by the end-users. The functions are in C++ and are called from Lua. I'm trying to make a Sleep() type function that will pause the script but not the program itself.
I was able to get it working by using threads and making one for each function. However, I want it to be an individual function. As in, instead of having it part of the CreateButton function and every other function, simply having a Delay or Sleep function that only halts the script, not the entire program.
Me being a novice at Lua, I really don't know how to go about this. Any help is appreciated.
I'd look into making a state machine using coroutines and message passing. Treat each button push like a c++ string that gets passed into coroutine resume. You can then build a little state machine that switches on the message. You can then do some UI work and then put the coroutine back to sleep till something sends it another message.
This is pretty handy if you have a state machine that does UI.
pseudo code:
c_obj:wait_for_message("mouse_down");
local message = coroutine.yield();
if(message == "mouse_down") then
update draw function.
end
c_obj:wait_for_message("mouse_up");
local message = coroutine.yield();
if(message == "mouse_up") then
Update UI..
update draw function.
end
etc...
To make your busy-waiting solution more efficient, how about using select() or similar to wait for some GUI events to process, rather than spinning? It seems like something you would need to do in the GUI regardless of the scripting side of things.