[erlisp-devel] undefined-symbol

[Eric Lavigne]

> > I am confused by this error message.
> >
> > ;
> > ; File: /root/erlisp/erlisp-cmucl/erlisp/src/manager.lisp
> >
> > ; In: DEFUN SYSTEM-MANAGER-PROCESS
> >
> > ;   (RECEIVE-WITH-MATCHER (COND-MATCHER M) (T M))
> > ; Error: (during macroexpansion)
> > ; Error in KERNEL::UNDEFINED-SYMBOL-ERROR-HANDLER:  the function
> > LISTEN-TO-SYSTEM-MANAGER is undefined.
> 
> In the files you attached there was no call to this function, and as I
> have not checked out the source I can't be sure, but apparently some
> macro calls LISTEN-TO-SYSTEM-MANAGER during its expansion.

Probably these calls occur in messaging.lisp. I forgot to include that
file, and I won't have access to that computer again until tonight.
Each process uses that function before send/receive to check whether
it has orders to die.

> 
> Now normally macroexpansion happens before functions are loaded.
> Therefore a macro should normally expand without calling functions
> (but may of course include function calls in the generated expansion
> code).

receive-with-matcher is a macro. listen-to-system-manager is called at
the beginning of that macro. Instead, the macro should just be
producing code that calls listen-... instead of calling listen-... and
then producing code. I see my mistake now.

> 
> When you really want to have a function to be available at
> macro-expansion time, you have to wrap the function in eval-when, like
> what now happens already with many functions in messaging.lisp:
> 
> (eval-when (:compile-toplevel :load-toplevel :execute)
>  (defun LISTEN-... (..)  ..)
> )
> 

I don't need it at macro-expansion time. I was treating macros as
though they were functions. This should be easy to fix now that I know
what the problem is. Without seeing the function call, how did you
figure out that I was calling that "missing function" from a macro?

Eric