[parenscript-devel] lisp-like lambda lists (keyword, option, and rest arguments)

[Vladimir Sedach]

Hi Red,

That looks awesome. I gave a though to adding something like this, but
as usual I assumed it would be hard and involve hacks. You proved me
wrong; I really like your implementation. Is there any effect on
plain-vanilla lambda lists? If not, then I say go ahead and push it.

Vladimir

On 7/30/07, Red Daly <reddaly at stanford.edu> wrote:
> In my local version I have added support for very Lispy lambda lists
> with keyword, optional, and &rest arguments.  Is this a feature we
> should add to the language?
>
> The Javascript convention for passing named arguments is to have an
> options variable that functions as a hash table for keywords.  I use
> this convention for passing keyword arguments in Parenscript.  Also,
> when a quoted symbol (e.g. a keyword) is found in a function call, the
> an options object is constructed.
>
> Here are a few examples
>
> (defun name (first last &key (prefix "Ms.") (middle
> ""))
>              (return (+ prefix " " first " " middle " " last)))
> =>
> function name (first last options) {
> options.prefix = options.prefix === undefined ? "Ms." : options.prefix;
> options.middle = options.middle === undefined ? " " : options.middle;
> return prefix + " " + first " " + middle + " " + last;
> }
>
> (defun vote (&optional (times 1)) ...)
> =>
> function vote (times) {
> times = times === undefined ? 1 : times;
> ...}
>
> (defun append (&rest lists) ...)
> =>
> function append()
> { lists = arguments.slice(0); ...}
>
>
> (name "John" "Cunningham" :prefix "Mr." :middle "Appleton")
> => name("John", "Cunningham", { prefix : "Mr." , middle : "Appleton" })
>
> I like having the extra lambda list features available in my own code.
> Should we add this to Parenscript?
>
> -Red
>
>
>
>
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