2015-08-30 14:30 GMT+02:00 Taylan Ulrich Bayırlı/Kammer <
taylanbayi...@gmail.com>:

> This is a bit of a crank idea, but here goes.
>
> Today I wasted some time trying to find the bug in the following piece
> of code:
>
>     (define (syntax-car syntax)
>       (syntax-case syntax () ((car . cdr) #'car)))
>
> Better error reporting in macro-expansion errors might have made it less
> painful, but maybe we can solve the problem itself.
>
> How about making 'foo turn into something like (__quote__ foo), and
> similar for `foo, #'foo, etc.?  Where __quote__ is just a synonym to
> quote, and the original works too.  Ideal would be a symbol that's not
> as noisy (in debug output) but still highly improbable to appear in user
> code and be accidentally shadowed.
>
>
You mean that #'x is synonymous to (syntax x), and that's where the problem
stems from?


> Maybe it would not be standards-compliant in the strict sense, but I
> believe it would be an improvement.
>
> Am I missing any obvious downsides?  Or any subtle ones?
>
>
I think that every lisper should know that 'x is synonymous to (quote x),
and in some contexts it might be desirable to bind a new meaning to the
"quote" form (and this is already done by some libraries, notably in the
(ice-9 match) module).

As to "syntax", the use of #'x is much rarer, and the idea that #'x is
(syntax x) is indeed a bit controversial. But this regards the whole
syntax-case macro system, and I think that it would be more valuable to
think how to fix its flaws, rather than change the very fundamentals of the
language.


Best regards,
M.

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