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Date:Mon Jun 25 11:21:52 1993 
Subject:BUG in POP11 
From:Helen McCall - PML Mast2 
Volume-ID:930625.02 

Can anyone help with a rather disastrous bug I have found in POP-11?

I have recently worked right through all my POP-11 code and modularised it in POP-11 sections. When I came to run it yesterday, I found that well tried and tested code no longer functioned!

I have found the problem, and need an answer urgently.

I have used the matcher arrow '-->' frequently, eg for assigning the bounds of arrays to limiting arguments in for-loops.

Unfortunately this language feature does not operate from within sections.

I have adapted this example from the teach files to demonstrate:


section $-banana
    =>
    TAIL
;
    define TAIL(L) -> RESULT;
        L --> [= ??RESULT] ;
    enddefine;

endsection;

TAIL([A B C D]) =>

gives the answer <undef RESULT>

If the section declaration is removed, the result is [B C D].

I believe the matcher is implemented as a macro, like switchon.  If so; will I also have the same problem with all my switchon conditionals?  I haven't had time to check this yet.

If it is a problem of sections being opaque to macros, is there a way of importing all the POP-11 language features which are implemented as macros?

Helen McCall.