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forwarded for JLL: compiling lisp code

    Date: 26 October 1982 11:00-EDT
    From: Joseph L. Leva <JLL at MIT-MC>
    Subject: compiling lisp code

    I'm having trouble compiling the lsubrcall function where the 2nd
    argument is flonum.  The following function works fine in the
    interpreter but gives an error when run from compiled code.

    (defun fls (fun a1 a2)
       ((lambda (fpt)
    	    (cond ((null fpt)(displa fun)(error '| has no LSUBR|)))
    	    (lsubrcall flonum fpt a1 a2))
        (get fun 'lsubr)))

The solution is to not use (LSUBRCALL FLONUM ...).  Just use 
(LSUBRCALL T ...).  Saying FLONUM tells the compiler that you only plan to
call subrs that support an extended calling convention, not just that
you plan to call subrs that return flonums.  +$ in fact does NOT support
this calling convention.  Since in fact very few LSUBRs support this
calling convention, while ALL subrs support the normal calling convention,
you should just use T and forget the FLONUM.

I guess the interpreter should have errored rather than looking like it was