Hi,
I'm trying to convert a Greenspun's 10th language into Common Lisp. In
cases such as the following, Python produces both a note (for the
unreachable code,) and a warning (for the bad arg to truncate during
constant folding.)
(defun foo3 ()
(let ((s "FOO"))
(typecase s
(double-float
(format t "a double: ~A~%" (truncate s)))
(t (format t "other: ~A~%" s)))))
My questions:
1) Should the compiler really be emitting warnings/errors in code it can
prove is unreachable? I think not, but am willing to revise my opinion.
2) Is there a way to locally suppress the warning? I've got millions
of cases like this, and post-processing the output doesn't seem to be
the right thing.
3) Is there a construct or hook/how hard would it be to hack the type
inferencer to support something like:
(defmacro op++ (x)
"Give me inline code for doubles if x is definitely a double,
else punt."
(if (inferable-type x 'double-float)
`(incf x)
`(adhoc-incf x)))
4) Section 5.3.5 of the CMUCL doc confuses me. I don't see how that
ecase statement can work.
Any illumination is appreciated,
Thanks,
Michael Naunton
