Re: Double unquote/unquote-splicing

[Nathan Trapuzzano]

Nathan Trapuzzano <address@hidden> writes:

> This is incorrect.  ``(a ,,@x) where x=(1 2 3) would evaluate to
> (\` (a (\, 1) (\, 2) (\, 3))).  The first comma in ,,@ has the effect of
> being applied member-wise to each element spliced out of ,@.  Cf. CLHS
> `Backquote' (http://www.lispworks.com/documentation/HyperSpec/Body/02_df.htm).

By the way, like in Common Lisp, what backquote/unquote/unquote-splicing
expand to is not defined.  What's defined is the effect of their
evaluation, so what I presented here doesn't _have_ to be the way ,,@
works.  For example, in Elisp, the expression in question may very well
expand to (\` (a (\, 1 2 3))) (as you say) so long as it is semantically
equivalent to (\` (a (\, 1) (\, 2) (\, 3))).