On May 26, 2011, at 18:32 , Pascal Costanza wrote:
>
> On 25 May 2011, at 21:40, Marco Antoniotti wrote:
>
>> Hi
>>
>> I don't think there is a reasonable objection to forbid a form like
>>
>> ((returns-something-funcallable arg1 arg2 ... argN) 1 2 3 ... N)
>>
>> from "working as expected". As Martin pointed out, if the return value of
>> the form is a "macro" then this would have to be interpreted in the
>> "regular" evaluation regime.
>
> The main issue I have with this is that at the moment, you have only explicit
> shifting operators (funcall/apply and function/symbol-function/fdefinition).
> A proposal like the one above would introduce implicit shifting.
>
> You already have implicit shifting in the sense that placing a symbol in the
> car or any of the cdr positions is already enough to fetch something from the
> function or the value namespace. However, you can only do this with explicit
> function/variable names directly in the "user" code, or by constructing the
> correct s-expressions in macro definitions. With a proposal like the above,
> you would add another level of implicit shifting.
>
> If I define a function, say (defun foo () 'bar), and a corresponding macro
> (defmacro foom () (foo)), then without explicit shifting and without macros,
> I can only use this to generate a variable name (baz (foom)), but not to
> generate a function name, because ((foom) baz) fails. With the proposal
> above, ((foom) baz) wouldn't fail. I prefer the explicitness of (funcall
> (foom) baz), especially because if you really, really, really want it
> implicit, you can still have it your way anyway.
I think this are good reasons, but not enough to disallow the following:
(<symbol or form-returning-a-function-not-a-symbol or lambda-expression>
...)
We already have
((lambda (x) (+ x 42)) 0)
Why not have
((compose 'first 'rest) '(1 2 3))
This would complicate the call protocol and require more explanation, but I
really don't see how it would harm the programmer.
Cheers
--
MA
>
>
> Pascal
>
> --
> Pascal Costanza
> The views expressed in this email are my own, and not those of my employer.
>
>
>
--
Marco Antoniotti, Associate Professor tel. +39 -
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