This is really interesting how managed to embed
J session into a .NET desktop application.
Regarding calling J from .NET code, what I meant
that, in particular since people can be put off
by J code, it could even be more upsetting when
it is intermingled with C# code, even if it is
constructing simple expressions and calls to J verbs
defined in script.
I think that it would cleaner if a calling convention
is established, so that from C# it looks almost like
calling another C# library.
One way to achieve this is how Web Services are built--
with the use of generated artifacts. You start with a
separate J script file with certain syntax conventions
for top-level verbs; then you write a few verbs and
run the generator; it will produce the C# wrapper class
with those verbs as public methods; it is referenced and
imported into C# program; then simply instanciated and
called as any C# class.
The syntax convention can even support multiple even
typed parameters. For example,
NB.@ int add(int a, int b)
add=: 3 : 0
'a b'=: y
a + b
)
which in the generated artifact wrapper class will become
class MyJLib {
JClass _j = new JClass();
...
public MyJLib() {
_j.Do("load '~user/myj/myjlib.ijs'");
}
...
public int add(int a, int b) {
_j.Set("a",a);
_j.Set("b",b);
_j.Do("z=: add a;b",b);
return _j.Get("z");
}
...
}
Now it is used simply:
MyJLib jl = new MyJLib();
int c = jl.add(11,22);
Note that such approach can easily generate other
interfaces: Web Services, Java beans, etc.
--- Alex Rufon <[EMAIL PROTECTED]> wrote:
> Hello Oleg,
>
> Thanks for the links. Your examples are actually better and I'll use them on
> Saturday.
>
> In the last part of your email, you mention something about letting the
> developers feel the
> awesome power of interactive execution of a J Session. Unfortunately, the J
> session window
> "scares" them and the "cryptic" way of getting data from a database actually
> puts them off. So I
> created an application called SmartEOE.IDE. I did it partly as a solution to
> the problem and to
> actually build a true Model-Viewer-Controller application in C#. The idea is
> that the developers
> have a tree window for each Library->J Script and an editor window for the
> actual scripts. They
> can then run and test the script in the embedded J window at the same time it
> allows them to
> retrieve data from familiar data sources and be able to send it to the J
> session. I took some
> screenshots and uploaded them to my website in:
> http://amrufon.spaces.live.com/photos/cns!2B169BDA829381E6!194/
>
> I will be emphasizing that before they embed their J scripts into their C#
> code, they can test
> it out with "real" data in the IDE. So when they are happy, they can then
> proceed and update
> their C# code with the J script, compile then deploy.
>
> Of course, I will still show them that there is an option where they can
> encapsulate all of the
> code that uses J so that it becomes a black box library. Still, my intention
> right now is to get
> them interested to use in-line J scripts and then later on convert C# modules
> into J verbs
> leaving the C# function as a wrapper method.
>
> Again ... thanks. :)
>
> r/Alex
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Oleg Kobchenko
> Sent: Tuesday, March 04, 2008 7:28 PM
> To: Chat forum
> Subject: RE: [Jchat] Re: the purity of quantified conception
>
> You should be prepaired that developers may not be as
> technically naive as their technical managers.
>
> http://www.csharp-station.com/HowTo/StringJoinSplit.aspx
>
> So starting with this example you should admit that
> it was simple enough so that the managers would get it
> and be lured to get you guys here, but now we gonna
> talk about some real cool stuff.
>
> .NET has vast standard libraries that handles numerous
> stock operations on simple objects like strings and collections.
> Whereas the forte of J is a few really powerful operations
> which generalize over higher-order structures in compact
> yet expressive notation(*).
>
> To expand on the Join example, you can show how to turn
> a matrix into HTML table in a one-liner.
>
> A second example of the .NET/J distinction can be that
> J has no dedicated operation for SubStr found in mostly
> any language library. However is can be easily done with
> Cut <;.0 and easily generalized to simultaneous multiple
> substrings in a one-liner and to a sub-matrix etc.
> Related examples here are running average (infix) and matrix
> convolution with <;.3 (another cut).
>
> Of course C# developers are really excited about Linq. So you
> must show Linq as they've never seen before, the way
> it is done in J
>
> http://www.jsoftware.com/jwiki/DB/Flwor
>
> (*) J notation best preserves its clarity when maintained
> separately from the client calling code, so its best not
> intermingle C# and J code, but keep a thin calling layer
> with clean separate C# and J sources. To this end,
> it is helpful to organize J code with externally callable
> entry points (top-level verbs) and some kind of convention.
> It is the same with SQL. Also keeping it separate makes
> use of the full power of J session for trial-and-error
> experimentation--another advantage of interpretive environment
> worth showing off.
>
>
> --- Alex Rufon <[EMAIL PROTECTED]> wrote:
>
> > The WAN is down so I can't work ... then I accidentally click on this email.
> >
> > I am basically the ONLY J programmer in our office. Were basically a C# and
> > VB.NET software
> > house but our core processing is done in J. Unfortunately, I am the only J
> > programmer (I can
> > repeat that as a mantra you know).
> >
> > For the longest time (going 8 years now), I've been trying to convince
> > other teams to adopt J
> > into their project ... and quite frankly I continue to fail.
> >
> > You said:
> > " People don't embrace J because, having been exposed to its awe-inspiring
> > qualities, they are
> > swept away by "the purity of quantified conception." That is likely to be
> > a factor, but
> without
> > a sense that J provides what they need in their actual context they'll
> > never go beyond initial
> > dabbling."
> >
> > Is VERY-VERY true.
> >
> > Last Saturday, I did another presentation to the Technical Managers trying
> > to convince them to
> > adopt J. But this time, I tried another approach (read this as being
> > sneaky). Instead of doing
> > examples on how it works, what the language is about and its capabilities.
> > I showed them how I
> > use C# with J to do the following:
> > 1. Array processing
> > 2. File processing
> > 3. Converting MS-SQL DataSet to SQL INSERT statements
> >
> > For the array processing, one of my example is creating the classic:
> > Select * from FRUITS where NAME in ('Orange','Apple','Banana')
> >
> > Normally, to do this in C#, they would have
> > string[] data = {"Orange","Apple","Banana"};
> >
> > What they actually need is to have the data in this format:
> > 'Orange','Apple','Banana'
> >
> > To do this in C# they have to loop through each of the item in the array
> > like so:
> > string result = "";
> > for (int i = 0; i < data.length; i++)
> > {
> > result += "'" + data[i].tostring() + "',";
> > }
> > // We have to remove the ending "," comma
> > if (result.length > 0)
> > {
> > result = result.trim(result.length - 1,1);
> > }
> >
> > Where if they use J, all they need to do is:
> > JSession objSession = new JSession();
> > string[] data = {"Orange","Apple","Banana"};
> > string result;
> > // Send the data to EOE
> > objSession.Variable("Temp1",(object)data);
> > // Process the data
> > objSession.Eval("res=: ',' charsep '''' ,~ each '''' with each Temp1");
> > // this can even be shortened with
> > // objSession.Eval("res=: datasep Temp1");
> > // Get the data back to C#
> > result= (string)objSession.Variable("res");
> > // SQL command
> > string sqlCommand = "Select * from FRUITS where NAME in (" + result + ")";
> >
> > And the other thing I pointed out is that in the original C# code, they
> > have to do this:
> > // We have to remove the ending "," comma
> > if (result.length > 0)
> > {
> > result = result.trim(result.length - 1,1);
> > }
> >
> > By putting things into the perspective of what they need now, I may have
> > some measure of
> > success. A few of the Technical Managers want to do another session on
> > Saturday but this time
> > they will be bringing their developers and wants a more detailed discussion
> > on the language.
> The
> > warehousing team is actually scheduling a meeting when I get back to the
> > Philippines for me to
> > help with their developers on data processing.
> >
> > I hope that this continues and I can encourage more people to adopt the
> > language. :)
> >
> > r/Alex
> >
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tracy Harms
> > Sent: Friday, January 25, 2008 4:17 AM
> > To: [email protected]
> > Subject: [Jchat] Re: the purity of quantified conception
> >
> > Randy MacDonald wrote:
> >
> > > Happy New Year, Tracy;
> >
> > A belated Happy New Year to you, too, Randy.
> >
> > >
> > > My personal thought about that "law" that says all systems of
> > > sufficient complexity are equivalent to lisp, my thought is,
> > > that all matter of sufficient temperature becomes plasma. True,
> > > but not of much use in the ordinary world.
> >
> > I had not recognized the allusion to that saying, so thanks for pointing it
> > out.
> >
> > > BTW, did the xkcd post have such an effect on the lisp community?
> >
> > Touch�
> >
> > Perhaps there is a fine line between desiring to see the beauty of J more
> > widely recognized,
> and
> > falling into factional squabbling. Lisp has had a small but fervent user
> > base for a long time,
> > and XKCD is one manifestation of that. At the point I start letting myself
> > think "if they only
> > knew..." I've fallen off the edge into fantasy.
> >
> > People don't embrace J because, having been exposed to its awe-inspiring
> > qualities, they are
> > swept away by "the purity of quantified conception." That is likely to be
> > a factor, but
> without
> > a sense that J provides what they need in their actual context they'll
> > never go beyond initial
> > dabbling.
> >
> > --
> > Tracy
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