William Harold Newman <william.newman@...> writes:
> > (PPRINT '``(FOO ,@',@S)) prints garbage.
> I get
> * (lisp-implementation-version)
> * '``(FOO ,@',@S)
> ``(FOO SB-IMPL::BACKQ-COMMA-AT S)
> doesn't look like a good result, unless we're in the realm of
> undefined behavior. Is that the garbage you're referring to?
Yes. It is not readable as needed. And if you disable pretty-printer,
you will see that ``(FOO ,@',@S) does not contain BACKQ-COMMA-AT at
> I spent a little time trying to figure out what ,,@ should mean (and
> similar constructs with ,@ preceded by a comma, like ,@,@ and the
> ,@',@ here) without much success, so I haven't yet figured out what
> to expect.
In this example? ``(FOO ,@',@S) or something similar.
CLtL2 gives explanations of many variants of combinations of these
operations, and CLHS describes a canonical representation of such
Greenspun's Tenth Rule of Programming as a reclame of Fortran