Re: [Bug-apl] )IN crashes

[Juergen Sauermann]

Hi  David,

I believe that native functions are a bit different from the "normal"
incompatibilities of user defined functions. The use of dyadic ⎕FX creates
an incompatible file format of the .atf files, while the other 
incompatibilities
merely create incompatible user defined functions.

Its like a letter written in a different language as opposed to a letter 
containing
some spelling mistakes.

I have added a note in the "native functions" chapter of the apl info file.

/// Jürgen


On 06/16/2014 07:02 PM, David B. Lamkins wrote:
> Understood.
>
> Given that perspective, I'd argue that )OUT should not warn about saving
> a native function. After all, what's being saved is only an expression
> using an extension to quad-FX.
>
> GNU APL should, of course, continue to support the )out -> )in
> round-trip of a workspace containing features specific to the
> implementation.
>
> Perhaps the documentation could include a notice similar to the
> following:
>
> ")OUT writes the contents of the workspace in a format that may be
> loaded by APL interpreters able to read an .atf file. APL interpreters
> differ in their capabilities; the ability for another APL interpreter to
> read an .atf file as written by GNU APL does not guarantee that the
> saved .atf file will load and run. In the case where program interchange
> is desired, it is the programmer's responsibility to write code that is
> compatible with all APL interpreters of interest."
>
>
> On Mon, 2014-06-16 at 16:26 +0200, Juergen Sauermann wrote:
> > Hi David,
> >
> > it is generally impossible in APL to check if a function uses a
> > feature or not.
> >
> > For example A ⎕CR B may or may not use dyadic ⎕CR (which is a GNU APL
> > extension),
> > depending on whether A is a variable or a function.
> >
> > And )OUT simply dumps the function's ⎕CR without further analyzing it.
> >
> > /// Jürgen
> >
> >
> > On 06/15/2014 09:45 PM, David B. Lamkins wrote:
> >
> > > Thank you. Confirmed working.
> > >
> > > On a related note: would it make sense to also warn about other GNU APL
> > > extensions when writing an )OUT file? I'm thinking in particular of
> > > lambdas and defined-function axis notation; these don't seem to cause
> > > problems with )OUT and )IN, but neither are they standard APL notation.
> > >
> > > On Sun, 2014-06-15 at 16:19 +0200, Juergen Sauermann wrote:
> > > > Hi David,
> > > >
> > > > thanks for isolating the fault. I fixed it in SVN 327.
> > > >
> > > > The fault was created by native functions being )OUT-ed and )IN-ed.
> > > > They are now handled properly, but the file created by )OUT is no longer
> > > > suitable as workspace exchange file when it contains native functions
> > > > (because native functions are a GNU APL extension that will not be
> > > > understood
> > > > by other APL interpreters).
> > > >
> > > > )OUT issues a warning for every native function being written.