Hi.

I want to embed an interpreter in my Free fpc game to provide an scripting interface. What are the available solutions? I have heard about Nemesis Pascal but i'm not sure if it works in FPC as it's website talks only about Delphi and Kylix.

HI,

FPC is compiled only

Alain

There are some scripting systems out there, RemObjects which I think Boguslaw was working on completing the latest version? There is another one that I think costs money, and maybe a few on TOrry.net which could be converted from Delphi to FPC.

I would probably try to use Pascal Script. It seams really good. I've never heard of nemesis so I can't really compare, it might be good also.

You can find more information about Pascal Script here:

http://wiki.lazarus.freepascal.org/index.php/Pascal_Script

and here:

http://www.remobjects.com/articles/?id={2FFC1EE9-F18D-4B11-9DE4-1BA0A79D0D04}

It looks very good, but i would preffer to avoid the use of Lazarus (Not that Laz is bad, i love it, but i want to keep the program small, with few dependencies). Also i think the Licence is GPL incompatible, which is very unfortunate :-(.

I found this one in the web:
https://opensvn.csie.org/PascalScript/
Seems very good, but it will need some work, the Virtual Machine is embedabble, but looks like the compier is a separated program.

I want to embed an interpreter in my Free fpc game...

How about LUA ?
http://www.lua.org/about.html

FreePascal bindings:
http://assoc.wanadoo.fr/thallium-software/thlua.en.html

- Jeff

Elio Cuevas Gómez wrote

It looks very good, but i would preffer to avoid the use of Lazarus (Not that Laz is bad, i love it, but i want to keep the program small, with few dependencies). Also i think the Licence is GPL incompatible, which is very unfortunate :-(.

1. The license is not GPL incompatible ?
2. You don't need lazarus, only if you want to do GUI.

I use Pascalscript since years, and it works very well.

Michael.

I want to embed an interpreter in my Free fpc game to provide an scripting interface. What are the available solutions? I have heard about Nemesis Pascal but i'm not sure if it works in FPC as it's website talks only about Delphi and Kylix.

There is remobjects' passcript too. It has compiled with FPC before.

Usually Delphi code is portable to fpc, so that doesn't have to be that big a barrier.

Elio Cuevas Gómez napisał(a):

As I understand you're asking about scripting languages in general, not only Pascal-syntax languages -- in that case I recommend Lua -- it's realy fast (one of the fastest scripting languages in it's class), it's easy to set up and realy easy to learn.

Nemesis relies heavily on the JVCL and the Scripting engine that is contained within it. Unfortunately, this engine uses Interfaces heavily, and FPC had issues with Interfaces last time the dev looked at a port.

FPC2.0x or maybe CVS build might be okay. Dunno though, one of the developers of FPC might like to comment on the status if IInterface, IUnknown and TInterfacedObject etc... IIRC there were serious reference counting issues at one point, but that was some time ago now.

I want to embed an interpreter in my Free fpc game to provide an scripting interface. What are the available solutions? I have heard about Nemesis Pascal but i'm not sure if it works in FPC as it's website talks only about Delphi and Kylix.

Yes! It seems like i was looking for, thank you very much :-)

Kornel Kisielewicz wrote

As I understand you're asking about scripting languages in general, not only Pascal-syntax languages -- in that case I recommend Lua -- it's realy fast (one of the fastest scripting languages in it's class), it's easy to set up and realy easy to learn.

That's correct. Pascal-like syntax would be nice, but is not required. I took a look at Lua and it seems like it would work. I miss the strict typing of Pascal but i can live without it :-)

I'm not a lawyer, but clause 3 of the license requires you to advertise RemObjects Pascal Script, which renders the license GPL incompatible. Of course i might be wrong, as i said IANAL.

2. You don't need lazarus, only if you want to do GUI.

I'm doing the GUI in SDL, but i still need the LCL to be able to use Pascal Script, right?

I use Pascalscript since years, and it works very well. Michael.

What does 'advertise' mean in this context ?

> 2. You don't need lazarus, only if you want to do GUI. I'm doing the GUI in SDL, but i still need the LCL to be able to use Pascal Script, right?

No; FPC is enough.

Michael.

Michael Van Canneyt wrote

What does 'advertise' mean in this context ?

3. You must have a visible line in your programs aboutbox or documentation that it is made using RemObjects Pascal Script and where RemObjects Pascal Script can be found.

i. e. You must put a link to RO homepage in your about box or your readme. Since i won't have an about box then the choice left is to put it in the readme, not a big deal since i do that sort of thing anyway, but is GPL-Incompatible nevertheless.

> I'm doing the GUI in SDL, but i still need the LCL to be able to use > Pascal Script, right? No; FPC is enough.

I guess i haven't gave PascalScript a fair view, i'll have a look later.

> How about LUA ? Yes! It seems like i was looking for, thank you very much :-)

Glad to help!

There is also an IDE for LUA, written in Delphi:

http://luaedit.luaforge.net/

It is probably overkill for what you need, but it might be useful to get some ideas on pascal+lua integration.

- Jeff

I don't see how this is incompatible, as I have no recollection of a clause in the GPL that says that you should not credit parts of the system... ?

But never mind, that's probably me being stubborn ;-)

Michael.

Take a look at Stallman's page about FreeBSD license and how freebsd "advertises Berkley and California unreasonably" or whatever. Personally I'm more of a FreeBSD style guy and I might even switch to FreeBSD over linux because of religion.

That page is a load of b*s*, because the LGPL requires just the same: your program must show the LGPL.

Nitpicking pure style. It's the spirit of the license that counts: Free software must remain free, and you must give credit where it's due.

The rest is food for lawyers without work.

Michael.

Of course you must show the license, but requiring all derived works to link to your web page in a readme or about box is something completely different. This sort of advertising clause is in fact incompatible with both the GPL and the LGPL. That's why the advertising clause in the new XFree86 license was so controversial, and why the X.Org fork was created.

Jonas

Michael Van Canneyt napisał(a):

Ugh, sorry to drop into this thread, but that reminded me of a problem I have. I'm not much oriented in licences, hence I ask your help -- I created a collection of FPC units, game-dev oriented, and I wanted to release them to the public for I (and maybe only myself ^_^) think they might be useful for others. After little tought I decided on LGPL - but a friend of mine brought to my attention, that people using the library will still be forced to open their sources if using my library -- which is not what I wanted.

What I want is to allow true freedom of using that library -- eg. for a closed-source commercial product too. The only thing I would like is that I am given credit for my work -- if a game uses the libraries, I want to be noted somewhere.

I heard something about the FPC RTL licence -- maybe thats the type of licence I need? Also, what would you guys suggest?

I fail to see the difference. If you must include the LGPL, then automatically you must identify which parts of the program are under the GPL (Assuming you don't want everything to be GPL) , which amounts to saying 'I used XYZ from ABC'. Whether this is as a link to ABC's website or not is just a detail. The idea is the same.

This sort of advertising clause is in fact incompatible with both the GPL and the LGPL. That's why the advertising clause in the new XFree86 license was so controversial, and why the X.Org fork was created.

Hm.
I'm currently in discussion with someone else about it, as well, so I'll risk the following question:

Can you explain WHY it is incompatible. I don't see why it is incompatible with the (L)GPL. Different, maybe. But incompatible ?

Michael.

The FPC license explicitly allows this.

You can use the FPC RTL license for that. It is LGPL, but explicitly allows the use in closed-source software.

Michael.

Michael Van Canneyt wrote

Can you explain WHY it is incompatible. I don't see why it is incompatible with the (L)GPL. Different, maybe. But incompatible ?

See http://lists.debian.org/debian-legal/2004/01/msg00284.html, and in particular http://www.gnu.org/licenses/gpl-faq.html#OrigBSD

The GPL only requires that you keep the credits in the sources, not that you advertise other people's work or products inside your own program, even if your program somehow uses that functionality. Imagine otherwise the credits list required for programs like the GIMP or so if each used library would have to be mentioned along with a link to some home page. You'd spend more time on maintaining that list than on actually adding new functionality.

Jonas

That is only required if people statically link to your units. If they compile them into a shared library and link against that, they do not have to open their sources. That's the whole point of the LGPL. The FPC RTL additionally also allows static linking, as long as you make your changes to the statically linked units (which are under the FPC RTL license) available.

What I want is to allow true freedom of using that library -- eg. for a closed-source commercial product too. The only thing I would like is that I am given credit for my work -- if a game uses the libraries, I want to be noted somewhere.

That is not possible with the GPL, LGPL or even the FPC RTL license. If you require such credit, people will also not be able to use your library in a (L)GPL product, because the resulting license will be incompatible with the (L)GPL..

Jonas

Michael Van Canneyt napisał(a):

Yeah, if it wouldn't I probably wouldn't use FPC :-).

That would ne fine. Is there a version of the FPC RTL Licence that I can use without modification? I mean one that doesn't explicite mention FPC RTL?

I agree that this may be a practical problem.

My concern is more principal.

(Actually, I have no real concerns, it's just a discussion ;) )

Michael.

Jonas Maebe napisał(a):

That is only required if people statically link to your units. If they compile them into a shared library and link against that, they do not have to open their sources. That's the whole point of the LGPL.

Yet, in case of a library that is based around classes that would be a real pain :-).

The FPC RTL additionally also allows static linking, as long as you make your changes to the statically linked units (which are under the FPC RTL license) available.

That's nice.

Understood. But I guess I can live with that :-). Yet, that brings up the idea of double-licencing -- licencing the library as (L)GPL for use with (L)GPL software, and a parallel licence for use in closed source software in which case attribution is needed. I guess that would be possible...

As long as you own all rights to the lib this is possible. However if you use parts with different licenses in your lib, this could be troublesome.

(e.g. Jedi-SDL headers or so)

Confusing point: since the headers contain no code by themselves, you cannot link to it. So technically, it is not included in your end product. So you are not "using" it at all...

We can keep making exercises like this all day long and find that actually, you can't use any third-party code. That kind of renders the whole issue void and meaningless :-)

Michael.

Marco van de Voort napisał(a):

Actually the Jedi-SDL headers are under the MPL. As for the problem itself -- the library uses the headers, but doesn't include them, so I guess the problem is not applicable?

This afaik isn't that far off from the FPC version of the LGPL.

As for the problem itself -- the library uses the headers, but doesn't include them, so I guess the problem is not applicable?

Easy to check. Is the implementation empty? Doesn't e.g. wrap and dynload?

One could of course always plead the "trivial" defense in such case.

In all my source files I at least like to give a web address so people can find out where to find more information, such as essays, articles etc. I've written about the source. If my website just so happens to contain some commercial product on it then that is too bad, I was just trying to leave my web site address in the source files so people could find more info about the unit. In fact a web address is usually more reliable than an email address since email addresses go dead or change and the user must visit the site to get the new email address. It also tracks how many users are actually using the unit and you can focus attention on the units that more people are using. What I don't agree with is having to say "this software was made in California" when in fact it was not. I think that was purely a local issue with BSD and they then changed it later, because their license was no longer created only by users in California, but spread worldwide. Maybe they just didn't expect the license to make it out of California and thought it would be a local license in the university.

I think in remobjects case all he was doing was pointing people to the website just like how I point people to my website. There are articles on remobjects on how to use the software, and useful info. No problem with giving web address according to human instinct, but problem with giving it according to GPL. Hey look at me, we are wasting all this time discussing whether it is "right" or not, this is the same problem as wasting time deciding whether we should put the list of web addresses in or not. I guess we are back at square one:
* in gpl people waste time debating the license
* in freebsd people waste time maintaining a list of URL's pointing to useful websites

I guess you choose which one is more a waste of time. Personally I think wasting time discussing a license is in fact more waste of time than just programming and adding some URL's to the file. Spam me? Sure if it is related to the software. I love targeted spam in source files.
As Michael says this is just a discussion though so don't take my comments too negatively :-) It's all in good nature.

Why is that too bad? The GPL is not against commercial products, and does not have any problems with you or anyone else putting URL's in their source files. It only has a problem with you if you want to force other people to put your url in their program and/or documentation.

The GPL does not forbid putting an URL anywhere, it only forbids forcing other people to put it somewhere.

Hey look at me, we are wasting all this time discussing whether it is "right" or not,

No, the original discussion was about whether or not a particular clause was (L)GPL compatible.

It is not a waste if you would otherwise unknowingly violate a license without the correct information.

Jonas