Re: what about dropping rest-lists?

[Sebastian Egner <sebastian.egner@xxxxxxxxxxx>]

I did a more systematic analysis of
the requirements and the alternatives.
It turned out that the real problem
is not the presence of the VALUES-
syntax, but the limits of the "just
list the variables"-syntax.

As a logical conclusion I will stretch
the "list the variables"-syntax to
include the "."-notation in
the cases it can cover (except the "no values"
case due to syntactic robustness), and
leave the VALUES-syntax in
for full generality and uniformity.

This design reduces the cases in which
VALUES *must* be used to
a) no values at all and 
b) a single variable receiving the list
of all values.

...hopefully there will be a new version
of the SRFI, soon.

Sebastian.

----
Dr. Sebastian Egner
Senior Scientist Channel Coding & Modulation
Philips Research Laboratories
Prof. Holstlaan 4 (WDC 1-051, 1st floor, room 51)
5656 AA Eindhoven
The Netherlands
tel:       +31 40 27-43166   *** SINCE 10-Feb-2005
***
fax:      +31 40 27-44004
email: sebastian.egner@xxxxxxxxxxx

srfi-71-request@xxxxxxxxxxxxxxxxx 17-05-2005 14:26

To:        Sebastian Egner/EHV/RESEARCH/PHILIPS@PHILIPS         cc:        srfi-71@xxxxxxxxxxxxxxxxx         Subject:        Re: what about dropping rest-lists?         Classification:

Sebastian Egner <sebastian.egner@xxxxxxxxxxx>
wrote at 2005-05-17T10:51:31+0200:
> And if you really need the rest-list thing (the day will come),
> the meaning will at least be obvious.

How about a keyword named "rest", with parens around the keyword
and
variable identifier?  The parens emphasize to human readers that the
"rest" name is in a keyword position and therefore should not
be
mistaken for a variable identifier?

    (let ( (a b c d      (values 1 2 3 4)) ) c)
 ;=> 3
    (let ( (a b (rest x) (values 1 2 3 4)) ) x)  ;=>
(3 4)
    (let ( ((rest x)     (values 1 2 3 4)) ) x)  ;=>
(1 2 3 4)

    (let ( (a b (rest x)    (values 1 2 3 4)) ) x)
    ;=> (3 4)
    (let ( (a b (rest rest) (values 1 2 3 4)) ) rest)  ;=>
(3 4)

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