Re: Supplied-p parameter in clojure similar to lisp lambda lists
I created a ticket http://dev.clojure.org/jira/browse/CLJ-1508
2014-08-18 11:02 GMT+08:00 dennis zhuang killme2...@gmail.com:
I think that adding a :p option to destructuring would be great:
(let [ {:keys [a b c] :p {a a-p}} params]
(if a-p
(println a)
(println a is not exists.)))
2014-08-17 20:05 GMT+08:00 Dave Tenny dave.te...@gmail.com:
Well, it took me a while to perhaps get what you were telling me here.
In my case I I had something like
(defn foo [ {:keys [bar ... more keys ...] :or {bar 1}} ] ...)
and I wanted to know whether the user had explicilty invoked foo with
:bar.
What wasn't clear to me was that :as solved this problem.
Reading http://clojure.org/special_forms#Special Forms--Binding Forms
(Destructuring)-Map binding destructuring
I guess I can see that it's telling me :as shows things that weren't in
the init-form, but that's with hindsight.
So, to emulated common lisp 'supplied-p' semantics, you can check the :as
form, which will **not**
contain :or values for keywords.
E.g.
user (defn bar [ {:keys [baz] :or {baz 'baz} :as all-keys} ] (println
baz all-keys))
#'user/bar
user (bar :bof 1)
baz {:bof 1}
nil
And not that the all-keys form does not show a binding for baz, and
that's what I wanted.
Just fyi in case anybody searches topics for 'supplied-p' again.
On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote:
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults
here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave@gmail.com wrote:
What is the commonly accepted technique for declaring/using
'supplied-p' type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/
HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and
various defaults, I want to know if a keyword was specified by the caller
(rather than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this,
but I'd like to avoid reinventing a wheel here if I can, and also to know
the idiomatic clojure way to do it.
Thanks for any tips.
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Re: Supplied-p parameter in clojure similar to lisp lambda lists
I don't think that a :p feature is necessary, since all you need to do to
emulate it is a
(:baz all-keys) to know if the user explicitly specified it. I.e. I think
the capability is already present in adequate form but the documentation on
map destructuring could be improved.
On Sun, Aug 17, 2014 at 11:02 PM, dennis zhuang killme2...@gmail.com
wrote:
I think that adding a :p option to destructuring would be great:
(let [ {:keys [a b c] :p {a a-p}} params]
(if a-p
(println a)
(println a is not exists.)))
2014-08-17 20:05 GMT+08:00 Dave Tenny dave.te...@gmail.com:
Well, it took me a while to perhaps get what you were telling me here.
In my case I I had something like
(defn foo [ {:keys [bar ... more keys ...] :or {bar 1}} ] ...)
and I wanted to know whether the user had explicilty invoked foo with
:bar.
What wasn't clear to me was that :as solved this problem.
Reading http://clojure.org/special_forms#Special Forms--Binding Forms
(Destructuring)-Map binding destructuring
I guess I can see that it's telling me :as shows things that weren't in
the init-form, but that's with hindsight.
So, to emulated common lisp 'supplied-p' semantics, you can check the :as
form, which will **not**
contain :or values for keywords.
E.g.
user (defn bar [ {:keys [baz] :or {baz 'baz} :as all-keys} ] (println
baz all-keys))
#'user/bar
user (bar :bof 1)
baz {:bof 1}
nil
And not that the all-keys form does not show a binding for baz, and
that's what I wanted.
Just fyi in case anybody searches topics for 'supplied-p' again.
On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote:
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults
here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave@gmail.com wrote:
What is the commonly accepted technique for declaring/using
'supplied-p' type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/
HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and
various defaults, I want to know if a keyword was specified by the caller
(rather than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this,
but I'd like to avoid reinventing a wheel here if I can, and also to know
the idiomatic clojure way to do it.
Thanks for any tips.
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Re: Supplied-p parameter in clojure similar to lisp lambda lists
Yep, it's an optional syntax sugar.
Indeed, you should use (contains? all-keys :baz) to check if :baz is
present in options. If :baz is present but it's value is nil,then (:baz
all-keys) returns nil too.
2014-08-18 18:57 GMT+08:00 Dave Tenny dave.te...@gmail.com:
I don't think that a :p feature is necessary, since all you need to do to
emulate it is a
(:baz all-keys) to know if the user explicitly specified it. I.e. I think
the capability is already present in adequate form but the documentation on
map destructuring could be improved.
On Sun, Aug 17, 2014 at 11:02 PM, dennis zhuang killme2...@gmail.com
wrote:
I think that adding a :p option to destructuring would be great:
(let [ {:keys [a b c] :p {a a-p}} params]
(if a-p
(println a)
(println a is not exists.)))
2014-08-17 20:05 GMT+08:00 Dave Tenny dave.te...@gmail.com:
Well, it took me a while to perhaps get what you were telling me here.
In my case I I had something like
(defn foo [ {:keys [bar ... more keys ...] :or {bar 1}} ] ...)
and I wanted to know whether the user had explicilty invoked foo with
:bar.
What wasn't clear to me was that :as solved this problem.
Reading http://clojure.org/special_forms#Special Forms--Binding Forms
(Destructuring)-Map binding destructuring
I guess I can see that it's telling me :as shows things that weren't in
the init-form, but that's with hindsight.
So, to emulated common lisp 'supplied-p' semantics, you can check the
:as form, which will **not**
contain :or values for keywords.
E.g.
user (defn bar [ {:keys [baz] :or {baz 'baz} :as all-keys} ] (println
baz all-keys))
#'user/bar
user (bar :bof 1)
baz {:bof 1}
nil
And not that the all-keys form does not show a binding for baz, and
that's what I wanted.
Just fyi in case anybody searches topics for 'supplied-p' again.
On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote:
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults
here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave@gmail.com wrote:
What is the commonly accepted technique for declaring/using
'supplied-p' type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/
HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and
various defaults, I want to know if a keyword was specified by the caller
(rather than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this,
but I'd like to avoid reinventing a wheel here if I can, and also to know
the idiomatic clojure way to do it.
Thanks for any tips.
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Re: Supplied-p parameter in clojure similar to lisp lambda lists
Well, it took me a while to perhaps get what you were telling me here.
In my case I I had something like
(defn foo [ {:keys [bar ... more keys ...] :or {bar 1}} ] ...)
and I wanted to know whether the user had explicilty invoked foo with :bar.
What wasn't clear to me was that :as solved this problem.
Reading http://clojure.org/special_forms#Special Forms--Binding Forms
(Destructuring)-Map binding destructuring
I guess I can see that it's telling me :as shows things that weren't in the
init-form, but that's with hindsight.
So, to emulated common lisp 'supplied-p' semantics, you can check the :as
form, which will **not**
contain :or values for keywords.
E.g.
user (defn bar [ {:keys [baz] :or {baz 'baz} :as all-keys} ] (println
baz all-keys))
#'user/bar
user (bar :bof 1)
baz {:bof 1}
nil
And not that the all-keys form does not show a binding for baz, and that's
what I wanted.
Just fyi in case anybody searches topics for 'supplied-p' again.
On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote:
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults
here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave@gmail.com javascript:
wrote:
What is the commonly accepted technique for declaring/using 'supplied-p'
type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and various
defaults, I want to know if a keyword was specified by the caller (rather
than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this,
but I'd like to avoid reinventing a wheel here if I can, and also to know
the idiomatic clojure way to do it.
Thanks for any tips.
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javascript:
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Re: Supplied-p parameter in clojure similar to lisp lambda lists
I think that adding a :p option to destructuring would be great:
(let [ {:keys [a b c] :p {a a-p}} params]
(if a-p
(println a)
(println a is not exists.)))
2014-08-17 20:05 GMT+08:00 Dave Tenny dave.te...@gmail.com:
Well, it took me a while to perhaps get what you were telling me here.
In my case I I had something like
(defn foo [ {:keys [bar ... more keys ...] :or {bar 1}} ] ...)
and I wanted to know whether the user had explicilty invoked foo with :bar.
What wasn't clear to me was that :as solved this problem.
Reading http://clojure.org/special_forms#Special Forms--Binding Forms
(Destructuring)-Map binding destructuring
I guess I can see that it's telling me :as shows things that weren't in
the init-form, but that's with hindsight.
So, to emulated common lisp 'supplied-p' semantics, you can check the :as
form, which will **not**
contain :or values for keywords.
E.g.
user (defn bar [ {:keys [baz] :or {baz 'baz} :as all-keys} ] (println
baz all-keys))
#'user/bar
user (bar :bof 1)
baz {:bof 1}
nil
And not that the all-keys form does not show a binding for baz, and that's
what I wanted.
Just fyi in case anybody searches topics for 'supplied-p' again.
On Saturday, June 21, 2014 7:22:13 PM UTC-4, Jason Felice wrote:
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults
here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave@gmail.com wrote:
What is the commonly accepted technique for declaring/using
'supplied-p' type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/
HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and
various defaults, I want to know if a keyword was specified by the caller
(rather than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this,
but I'd like to avoid reinventing a wheel here if I can, and also to know
the idiomatic clojure way to do it.
Thanks for any tips.
--
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Re: Supplied-p parameter in clojure similar to lisp lambda lists
If you destructure the parameters like this:
(defn f [ {:as a-map}] ...)
You can use map primitives on a-map. But you can also supply defaults here.
On Jun 20, 2014 2:14 PM, Dave Tenny dave.te...@gmail.com wrote:
What is the commonly accepted technique for declaring/using 'supplied-p'
type lambda list functionality in clojure?
http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/sec_3-4-1.html
I have some clojure functions with a large number of keywords and various
defaults, I want to know if a keyword was specified by the caller (rather
than defaulted) in some cases.
Certainly I could implement my own destructuring macros that did this, but
I'd like to avoid reinventing a wheel here if I can, and also to know the
idiomatic clojure way to do it.
Thanks for any tips.
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Supplied-p parameter in clojure similar to lisp lambda lists
What is the commonly accepted technique for declaring/using 'supplied-p' type lambda list functionality in clojure? http://www.ai.mit.edu/projects/iiip/doc/CommonLISP/HyperSpec/Body/sec_3-4-1.html I have some clojure functions with a large number of keywords and various defaults, I want to know if a keyword was specified by the caller (rather than defaulted) in some cases. Certainly I could implement my own destructuring macros that did this, but I'd like to avoid reinventing a wheel here if I can, and also to know the idiomatic clojure way to do it. Thanks for any tips. -- You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups Clojure group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
