From octave-maintainers-request at bevo dot che dot wisc dot edu Wed Dec 18 14:03:11 2002
Subject: Re: Creating a standalone executable
From: Paul Kienzle <pkienzle at jazz dot ncnr dot nist dot gov>
To: JD Cole <jdcole at san dot rr dot com>
Cc: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>,    octave-maintainers@bevo.che.wisc.edu
Date: Wed, 18 Dec 2002 15:03:03 -0500

octave_value is part of liboctinterp.  Many of the classes on which the
octave_value types are based are defined in liboctave.  E.g., liboctave
defines Matrix, which is wrapped by octave_matrix.

octave_value implements dynamic typing, so all operations must be looked
up at run time every time they are invoked.  

Things like the * operator for the Matrix class, however, are resolvable
at compile time.

Most of the code in e.g., src/DLD-FUNCTIONS, operates directly on values
of the underlying type rather than on the octave_value item.

Paul Kienzle
pkienzle at users dot sf dot net


On Wed, Dec 18, 2002 at 11:50:41AM -0800, JD Cole wrote:
> Yes, that is why I was curious about the history of install_ops/_types.
> 
> Just to clear something up, when I'm performing octave_value addition, 
> as in the code snippet below, this uses liboctinterp operators, not 
> liboctave operators?
> 
> The way I "understand" now I thought that ov operators were all defined 
> in liboctave, so in the following code I shouldn't need functionality 
> from liboctinterp, right? (I admit I'm a bit confused at this point.)
> 
> JD
> 
> | source code (a.cc)
> > | =========
> > | #include <octave/oct.h>
> > | #include <octave/ops.h>
> > | #include <iostream>
> > | 
> > | using namespace std;
> > | 
> > | int main(int argc, char *argv[])
> > | {
> > |   install_types ();
> > |   install_ops ();
> > |   octave_value a(10.0),b(20.0),c;
> > | 
> > |   c = a + b;
> > | 
> > |   c.print(cout);
> > |  
> > |   return (0);
> > | }
> 
> 
> John W. Eaton wrote:
> 
> >On 18-Dec-2002, JD Cole <jdcole at san dot rr dot com> wrote:
> >
> >| This may be a C++ ignorant question, but, what was the motivation behind 
> >| installing operators/types "manually" rather than having them 
> >| instantiated in the type class?
> >
> >Mixed-type operations, I think.
> >
> >But I think it would still be possible to have them installed
> >automatically, using some static object -- the constructor of the
> >object would call the appropriate function for installing the
> >operators defined in the file where the static object appears.  The
> >constructor for the static object would be called automatically when
> >the object is loaded.  That only leaves the question of ensuring that
> >everything is initialized in the proper order (probably not too hard
> >to do, but would require some care).  But as Paul points out, maybe
> >you don't want to initialize all of this every time you use
> >liboctinterp?
> >
> >jwe
> >
> >  
> >
>