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

[Red Daly]

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