The curse of Dennis D. Spreen

It would be great if, rather than telling us it is great and giving us sample code, to actually show us an example of how it is used. Can’t glean much from what has been posted and not interesting enough without a real world example to want to go and download and try it out. Just saying.

😉 download and try the included examples!

Any reason why only XE5-XE7 apart from “I did not test it on any other versions”?

[…] Just read a n article about Lua: […]

@stefan: I did not test it on any other versions. Should work with XE3 + XE4 as well, and with some modifications (MarshaledAString) on older versions as well

Thank you!

Hello! It looks great. I am so disappointed that it isn’t compatible with my Delphi version (XE2). I tried to make some modifications but there were too many to do and finally I gave up. I have to buy XE7. 🙂

It would be possible to rewrite the lib for usage with older Delphi versions (2010+), but as a professional developer I think the delphi maintenance is a great deal – with a fixed price/year you’re always up to date with the latest version – and why not use those new functions they offer? As this is not a commercial but an open source library, you’re free to fork and rewrite it for other versions – but I don’t want to spend my time for this task… 😉

[…] Head over and download the full source code for the Lua scripting interpreter for Delphi XE7 Firemon… […]

Keep the hardwork, Samples are very Clear, thanks for contribuiting to the Delphi Community, and thanks for the Effort 🙂

Any chance you could release it under a different license, compatible with commercial/proprietary applications? I would like to use it in a product that includes commercial third-party libraries that I purchased but I cannot distribute in source code. MPL would be great, or even a commercial license – I wouldn’t mind paying for it.

Sorry I didn’t realize the license is MIT. The comments in the code still mention GPL.

Hello, congratulations on your project, however it is happening one error when compiling.
There is the overloaded version of ‘RegisterFunction’ that can be called with arguments These

It is not work on Delphi XE5

Source:
uses …, VerySimple.Lua, VerySimple.Lua.Lib;
…
procedure TForm1.Test(Sender: TObject);
var
Lua: TVerySimpleLua;
begin
Lua := TVerySimpleLua.Create;
Lua.DoFile(‘example1.lua’);
Lua.Free;
end;

Error code:
[dcc32 Error] VerySimple.Lua.pas(395): E2250 There is no overloaded version of ‘RegisterFunction’ that can be called with these arguments
Error in line:
RegisterFunction(L, AObject.ClassType, AObject.ClassType.MethodAddress(Func), FuncName);

hmm, it runs with my XE5 Version without any error
Embarcadero® Delphi® XE5 Version 19.0.14356.6604

It is not work on Delphi XE5 Prosessional,me too.

ok, I’ll reinstall Delphi XE pro (+ latest update) and take a look

It fine works on Delphi XE7, XE8. I’m a little surprised by the size of the compiled file. “Hello World!” – Example1.exe – 6,174,208 bytes

Fixed XE5 and moved from GoogleCode to GitHub (needs some Git polish)!

Thanks , it now fine works on Delphi XE5 Pro.

@Flegont: About exe sizes, see second chart

http://blogs.riversoftavg.com/index.php/2014/05/12/performance-comparison-from-delphi-2010-to-xe6-part-2/

My son pointed me to LUA in my quest to find a decent embedded language. I am looking forward to trying this wrapper.

By the way, your write-up on the curse almost brought tears to my eyes. Every programmer with enough gray hair and even a shred of humility can surely relate. I always tell our green programmers, “never assume a snippet of code or the tiniest of utilities that you produce will not escape into the wild.”

very good.
Can add android lua.so,dll file?

Great work!
But where to find the Lua.so file ? thanks.

Added the missing iOS/Android lib files (lost during google code transfer). You may easily create your own, see previous blog posts about “How to create LibLua for iOS/Android/Mac”.

Good job! Can you tell me how to access the delphi custom class object from Lua? thanks

How could I use TclientDataSet using this scripting ?

hello, when i try to register more then 32 functions (via RegisterFunctions(Self)) my program going to crash, wtf is it?

also catching “PANIC: unprotected error in call to Lua API (not enough memory)” when try to register some functions, and using 200-lines lua script. wtf ?

third question: is this component thread safe ? can i use TVerySimpleLua in this construction:

type
TMyThread = class(TThread)
private
FLua: TVerySimpleLua;
…
end;

…
constructor TMyThread.Create;
begin
FLua := TVerySimpleLua.Create;
FLua.DoFile(…); // executing one script file in every thread !!!
…
end;

——————–

will it conflict or not ?
thank you.

To reduce the size of the compiled file, remove unnecessary unite FMx.Dialogs on line = 173 in VerySimple.Lua (-4500KB).

Hey, Alex. Can you help me? Why i cant register more than 32 functions via RegisterFunctions(Self)?

it seems that the Lua stack isn’t properly expanded as needed (stuck at
20 by default), so you may just add this line at first in the
PushFunction in the VerySimple.Lua.pas (Line 427):

class procedure TVerySimpleLua.PushFunction(L: lua_State; Data, Code:
Pointer);
begin
if lua_checkstack(L, 3) 1 then // assure enough stack space
Exit;

// prepare Closure value (CallBack Object Pointer)
…

I will later update every stack push with stack space checking.

Works very nicely in general, but is there a way to pass and array as an argument? I have a need to rewrite code I used previously with luawrap.

Okay, worked out how to do it. Thanks for your hard work, very useful.

About an bug in old XE5, same thing on v19.0.13476.4176

re: [dcc32 Error] VerySimple.Lua.pas(395): E2250 There is no overloaded version of ‘RegisterFunction’ that can be called with these arguments

Error going exactly from function overloading, and can be fixed very easy.

Orig : RegisterFunction(L, AObject.ClassType, AObject.ClassType.MethodAddress(LMethod.Name), LMethod.Name);

Add @ sign before L to show complier, it’s realy pointer type.
Show complier real type of AObject.ClassType using TClass(…)

Fixed : RegisterFunction(@L, TClass(AObject.ClassType), AObject.ClassType.MethodAddress(LMethod.Name), LMethod.Name);

Works well…

Thanks for your hard work!

but is there a way to pass and TFileStream as an argument override DoFile method?

How to use decoda debugging delphi program?

Dear dennis, Could you please provide multiple lua file and using the “module” “require” function called example?

thanks!

I am attempting to use the very simple lua code but when I try sending a string parameter to lua and return it. it’s only getting the first letter of the string.

Fix for XE5 in VeriSimple.lua.pas
Original : RegisterFunction(L, AObject.ClassType, AObject.ClassType.MethodAddress(LMethod.Name), LMethod.Name);
Fixed : RegisterFunction(Pointer(L), (AObject.ClassType), AObject.ClassType.MethodAddress(LMethod.Name), LMethod.Name);

Sir, whoever you are, thank you so much for this! In my own application through the years I’ve develop a kind of custom script language with minimal functions and capacity but poeple are always asking for more and it becomes more difficult to improve my stuff since I’m not really good enough to re-write a kind of c-langage or something… But now, after having tried your examples, I am dreaming of integrated instead LUA script in my stuff. All the mechanic of functions, variables, with the loop, the if statement, etc. which is mainly the hard part, could be handle by the LUA interpretor and then, for the actual things related with our applications, then, LUA script would call my routines. Wow! I can’t wait to integrate that. Thank yo so much!
I though it was difficult to do that!
Denis.

OMG, Thank you, kind Sir!
You do fantastic job with this lib!

thank you very much, 32 functions problem resulved!! you seems to forget updating your github version?

VerySimple.Lua can add support for linux?

I found in a previous article, you have a Lua for Delphi 2010. I would like to use this but it uses Lua 5.1. Do you know if it would work to just change to Lua 5.3?

Klasse Website. Vielen Dank.

Dunno what I am doing wrong, but trying your libs within a 64bit delphi application (even the examples) does not work at my side.

What I did:
(1) changed the destination platform to 64-Bit
(2) created new mylua.dcu
(3) created new VerySimple.Lua.Lib.dcu
(4) created new VerySimple.Lua.dcu

ever since I tried I am getting
an
ELuaLibraryLoadError:

Failed to load Lua library “..\..\DLL\Win64\LUA5.3.0.DLL”

I am using Delphi XE5 so do you have a suggestions what I am doing wrong? (It works out perfectly when creating 32-Bit DCU’s and setting DLL and application to 32Bit).

Thanks in advance

I use your libs witin 32bit Delphi application.
Everything works great on 32/64 platforms. Win XP, 7, 8, 10.
But once, on Win 10 64 I got an error “Failed to load Lua library Lua5.3.0.dll”
Then I downloaded Lua5.3.5.dll in the Internet and renamed it to Lua5.3.0.dll and replaced the old one.
Everything began to work again.
What was the problem?

@Flegont: It does work with Lua 5.3.5 – see my new post on how to build it on windows or obtain the official (debug) DLLs (see link in same post). I can’t help you though why it stopped working with lua.5.3.0.dll – it still runs on Win10/64 with that version…

Thank you, your clarification is sufficient. Error Lua5.3.0.dll on Win 10 64bit was observed only on one user (and was easily fixed, as I said earlier). In all other cases known to me, Lua5.3.0.dll works correct with Win 10 64bit

Every 5.3.x-Version is just a bugfix version without adding/changing of features so they should work right away

I’ve been much struggeling with anonymous lua functions. I’ve found a rather slow and ugly way to call them from Delphi by adding a static function to the global scope. But that’s not very efficiant.
I was hoping for something like …
lua_Function lua_toluafunction (lua_State *L, int index);
void lua_pushluafunction (lua_State *L, lua_Function f);
Is anything like that possible?

Hi, could you explain me how to get it more results from LUA script?

I see example 6. In my case I need push some double values to lua script and get some double value as results. With one result it’s ok but I don’t understand how get more that one result.

@array81: just take a look at the example 6:
lua_call(L, 2, 1); // call function with 2 parameters and 1 result

if your function returns two results then
lua_call(L, 2, 2); // call function with 2 parameters and 2 results

now get the result from the stack with_
int ret1 = lua_tonumber(L, -2);
int ret2 = lua_tonumber(L, -1);

see https://www.lua.org/pil/25.2.html

lua_pop(L, 2); // don’t forget to pop both values at the end!

Firstly thank you for these useful components. I have used this, together with verysimple.xml, to create an extensible spreadsheet where users can code their own functions and cell data is stored in xml nodes.

Now though I want to extend Lua to call a function in my GUI – to prompt for user input – and have spent many hours trying and failing to work out how to do this. Any help would be very gratefully received!

@John: you could make a package (see “example 5 create a package” with two ways creating a package) which holds your functions

If I use math.log10() in my lua function, I get an error. But, the cmd window closes immediately so I can’t find the reason. If I call the function directly from the lua file, it does give the correct answer.
Can you give me an idea how to fix this problem?

@Bruce: Please send me an example script, thanks

@Bruce: don’t use math.log10(x) anymore, it’s been replaced by math.log(x, base)

Hello,
I am testing VerySimpleLua with Delphi 10.2 / Windows 10.
Trying create text file and write into it “Hello World”, I get Erreur E/S 6.

Could you help me please.
Regards
Pierre

Hi,

As a total newbie in LUA, here is my problem:
I would like send an integer value from Delphi to a lua script variable called “TOTAL_TANK” then launch a lua function with no argument called “config_tanks()”.
How to do that please.

Why not calling a Lua function with the total_tank var, e.g. “config_tanks(TOTAL_TANK)” and then set the global var inside that lua function? You may take a look at example 6 on how to call lua functions and adjust the paramcount there.

Is there a way to catch (or verify programmatically) syntactic errors in the LUA script?
Currently in a console program I get “PANIC: unprotected error in call to Lua API (attempt to call a nil value)”.
With the same (erroneous) script a VCL application just crashes.

@Luca: Send me an example, I’ll take a look then

I solved my previous problem. Thank you.
Now I am facing a strange problem running my program on a panel PC with Windows 10 Enterprise 2016 LTSB.
Is there any dependency for the Lua DDLs in your installation package?