[parenscript-devel] lisp-like lambda lists (keyword, option, and rest arguments)
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
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@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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My changes are now synced up with the repository. Feel free to play around with the latest and greatest. You might notice that the function toArray() is not defined, required for &rest processing. toArray is simply.. (defun to-array (array-like) (let ((result (array))) (dotimes (i array-like.length) (setf (aref array i) (aref array-like i))))) -Red Vladimir Sedach wrote:
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@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
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
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Red Daly <reddaly@stanford.edu> writes:
My changes are now synced up with the repository. Feel free to play around with the latest and greatest.
You might notice that the function toArray() is not defined, required for &rest processing. toArray is simply..
Having &rest is really awesome. . .
(defun to-array (array-like) (let ((result (array))) (dotimes (i array-like.length) (setf (aref array i) (aref array-like i)))))
Yet another reason to have a delayed "include this function iff it is used" option . . . which is my vote for the next awesome feature ;-) [...]
I added code to do the to-array stuff in-line. That eliminates the need for to-array as a function, but it also saves some copying and consing time since we know the number of effective-args at compile-time. Vladimir On 8/1/07, Red Daly <reddaly@stanford.edu> wrote:
My changes are now synced up with the repository. Feel free to play around with the latest and greatest.
You might notice that the function toArray() is not defined, required for &rest processing. toArray is simply..
(defun to-array (array-like) (let ((result (array))) (dotimes (i array-like.length) (setf (aref array i) (aref array-like i)))))
-Red
Vladimir Sedach wrote:
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@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
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
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participants (3)
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John Fremlin -
Red Daly -
Vladimir Sedach