scripting languages

hi all =)

just read Paolo's very nice blog entry about the progress
made in kboard:

	http://pcapriotti.wordpress.com/2007/07/18/kboard-an
-update/

in it, Paolo notes that it is using Lua for scripting. out
of curiosity ... 
why Lua? i know it's popular among certain online games, but
other than 
that ... =)

personally, i'd love to see more and more KDE apps that
support scripting 
supporter either-or-both QtScript / Kross. they do have
slightly different 
approaches, but if we can get enough apps with JavaScript
support (which we 
get with either QtScript or Kross) then we can start to
offer a 
scripting "lingua franca" for desktop apps.

people can then learn one language (that they may well
already know) and go 
nuts in kde.

however, i'm sure there's a very good reason for Lua in this
case. as such, 
i'm curious to know what it is =)

-- 
Aaron J. Seigo
humru othro a kohnu se
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KDE core developer sponsored by Trolltech

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On Wednesday 18 July 2007 05:42:12 Aaron J. Seigo wrote:
> hi all =)
>
> just read Paolo's very nice blog entry about the
progress made in kboard:
>
> 	http://pcapriotti.wordpress.com/2007/07/18/kboard-an
-update/
>
> in it, Paolo notes that it is using Lua for scripting.
out of curiosity ...
> why Lua? i know it's popular among certain online
games, but other than
> that ... =)

Hi Aaron,
when we started playing with the theme engine, Kross was
part of KOffice and I 
remember that I had troubles figuring out how to compile it
separately.
At the time, there was no such trend of using Javascript
throughout KDE for 
scripting, al least, I did not notice it. I remember that
Kate had tried both 
Lua and Javascript (and eventually decided for Javascript)
and that Amarok 
used (still uses?) ruby.
Having one language for scripting in the whole of KDE is
certainly a good 
thing, but I must say that making a transition to Kross
(which for us would 
probably also mean extending Kross to support Lua, since we
already have a 
lot of Lua code) is not a top priority at the moment for
us.
While we're at it, can you point me to the projects that are
now using Kross / 
QtScript? I know about Plasma, but... how much of the
scripting framework for 
it has been done?

Paolo
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On Wednesday 18 July 2007, Paolo Capriotti wrote:
> On Wednesday 18 July 2007 05:42:12 Aaron J. Seigo
wrote:
> when we started playing with the theme engine, Kross
was part of KOffice
> and I remember that I had troubles figuring out how to
compile it
> separately. 

yes, it has come a long way in the last 6 months.

> At the time, there was no such trend of using
Javascript 
> throughout KDE for scripting, al least, I did not
notice it. I remember
> that Kate had tried both Lua and Javascript (and
eventually decided for
> Javascript) and that Amarok used (still uses?) ruby.

yes, kate still uses js and amarok is using ruby.

> Having one language for scripting in the whole of KDE
is certainly a good
> thing, but I must say that making a transition to Kross
(which for us would
> probably also mean extending Kross to support Lua,
since we already have a
> lot of Lua code)

that does make it more difficult indeed. how much Lua do you
have?

> is not a top priority at the moment for us. 
> While we're at it, can you point me to the projects
that are now using
> Kross / QtScript?

seems just SK and koffice use Kross. QtScript is also pretty
new. it's not 
like you guys are behind, it's just nice to get people onto
the leading edge 
as quickly as possible...

> I know about Plasma, but... how much of the scripting 
> framework for it has been done?

there are two people working on QtScript, both having
started within the last 
couple weeks and both are experienced qt bindings people. so
i'm encouraged 
by that.

if KBoard doesn't have js support, well .. it's not like
it's a huge loss. 
just would be nice to have as many app as possible in line
with each other.

cheers =)

-- 
Aaron J. Seigo
humru othro a kohnu se
GPG Fingerprint: 8B8B 2209 0C6F 7C47 B1EA  EE75 D6B7 2EB1
A7F1 DB43

KDE core developer sponsored by Trolltech

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On Wednesday 18 July 2007 11:57:54 Aaron J. Seigo wrote:
> > Having one language for scripting in the whole of
KDE is certainly a good
> > thing, but I must say that making a transition to
Kross (which for us
> > would probably also mean extending Kross to
support Lua, since we already
> > have a lot of Lua code)
>
> that does make it more difficult indeed. how much Lua
do you have?

"wc -l" tells me 2077 lines, so not that much as I
thought. Converting those 
to js would be a major pain, but it's probably feasible in a
short time.
Losing the Lua code, however, has the disadvantage of
damping my motivation to 
add Lua to the languages supported by Kross (yes, I actually
had that in mind 
since a long time).
I think we will stick to Lua for themes for the time being.
If we will add 
real scripting support (like the possibility of defining new
games in a 
scripting language), we will surely use Kross for that. In
the meanwhile, 
I'll investigate about how to extend Kross, and if Lua can
be included (there 
may be some problems because of the stack based C
interface).

>
> > is not a top priority at the moment for us.
> > While we're at it, can you point me to the
projects that are now using
> > Kross / QtScript?
>
> seems just SK and koffice use Kross. QtScript is also
pretty new. it's not
> like you guys are behind, it's just nice to get people
onto the leading
> edge as quickly as possible...

I still have to understand what QtScript actually is for.
What's the advantage 
of using it instead of Kross, which seems strictly more
general? Any 
pointers?

> if KBoard doesn't have js support, well .. it's not
like it's a huge loss.
> just would be nice to have as many app as possible in
line with each other.

Agreed.

Paolo
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Aaron J. Seigo wrote:
> however, i'm sure there's a very good reason for Lua in
this case. as such, 
> i'm curious to know what it is =)

Paolo can probably contribute more, but here are my 2 cents

Lua is actually commonly used in the gaming industry: I have
attended a 
couple of talks in the Game Developers Conference about it,
3 or 4 years 
ago. It is used not only for interface configuration (as in
WoW), but 
actually for game logic as well and level scripting.
Psychonauts for 
example is reportedly written as a C++ graphics engine that
uses Lua for 
all game behavior and AI.
I suspect that one of the reasons for this is that the Lua
runtime is 
very small (100Kb) and fast, and the syntax is easier for 
non-programmers to get. Also, one big advantage for game
companies that 
does not apply to us is probably the MIT license, which is
more 
forgiving for embedded scenarios, as the Lua runtime is
usually compiled 
in the game executable.
Lua's main author gave a talk about it at FISL 2005. One of
the 
advantages of it for configuration is that it is both a
scripting and a 
data description language, and it is easily binded to C/C++
code.
It would be nice to have Lua script support in Kross imo. It
is not as 
widely used as some of the other languages for sure, but it
has very 
special features related to how memory is managed that make
it specially 
suitable for writing AI finite-state machines. It is not a
priority for 
application scripting imo, but as KBoard already has several
interesting 
uses of Lua it can be interesting to know how this evolves.

Regards,
Mauricio Piacentini
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On Wednesday 18 July 2007, Paolo Capriotti wrote:
> On Wednesday 18 July 2007 11:57:54 Aaron J. Seigo
wrote:
> > > Having one language for scripting in the
whole of KDE is certainly a
> > > good thing, but I must say that making a
transition to Kross (which for
> > > us would probably also mean extending Kross
to support Lua, since we
> > > already have a lot of Lua code)
> >
> > that does make it more difficult indeed. how much
Lua do you have?
>
> "wc -l" tells me 2077 lines, so not that much
as I thought. Converting

that's still quite an investment in code. yeah, no point in
porting all that 
at this point.

> > seems just SK and koffice use Kross. QtScript is
also pretty new. it's
> > not like you guys are behind, it's just nice to
get people onto the
> > leading edge as quickly as possible...
>
> I still have to understand what QtScript actually is
for. What's the
> advantage of using it instead of Kross, which seems
strictly more general?
> Any pointers?

flexibility, speed vs kjs and it's very lightweight.

-- 
Aaron J. Seigo
humru othro a kohnu se
GPG Fingerprint: 8B8B 2209 0C6F 7C47 B1EA  EE75 D6B7 2EB1
A7F1 DB43

KDE core developer sponsored by Trolltech

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On Wednesday 18 July 2007, Mauricio Piacentini wrote:
> Aaron J. Seigo wrote:
> > however, i'm sure there's a very good reason for
Lua in this case. as
> > such, i'm curious to know what it is =)
>
> Paolo can probably contribute more, but here are my 2
cents 
> Lua is actually commonly used in the gaming industry: I
have attended a

alright =) it's the usual "this language is good for my
domain".

-- 
Aaron J. Seigo
humru othro a kohnu se
GPG Fingerprint: 8B8B 2209 0C6F 7C47 B1EA  EE75 D6B7 2EB1
A7F1 DB43

KDE core developer sponsored by Trolltech

_______________________________________________
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