Be sure to also implement the version of get which takes a not-found
argument so that your objects will work with map code which uses this
functionality.
(defrecord map-like-object [field-1 field-2 etc]
clojure.lang.IFn
(invoke [this k] (get this k))
(invoke [this k not-found] (get this k not-found)))
sincerely,
--Robert McIntryre
On Fri, Dec 31, 2010 at 11:04 AM, Alyssa Kwan <alyssa.c.k...@gmail.com> wrote:
> Generating readable code for IDEs is not a good reason. You should
> think carefully about variable capture and decide which you want.
> Usually, in a macro-generated defn, I do want to capture the
> parameters, so I would use ~'this.
>
> On Dec 30, 11:54 pm, André Thieme <splendidl...@googlemail.com> wrote:
>> Am 31.12.2010 03:29, schrieb Alex Baranosky:
>>
>>
>>
>>
>>
>> > I've been playing with making a macro to encapsulate Stuart's post, like
>> > this:
>>
>> > (defmacro defrecord-ifn [name & args]
>> > `(defrecord ~name ~...@args
>> > clojure.lang.IFn
>> > (invoke [this key] (get this key))))
>>
>> > (defrecord-ifn Foo [a b c])
>>
>> > (def foo (Foo. "A" "B" "C"))
>>
>> > (prn (map foo [:a :c])) => ("A", "C")
>>
>> > I get the error:
>>
>> > "No such var: user/this". I guess this is because it is expanding
>> > 'this' to 'user/this'. What is the proper way to get a macro like this
>> > to expand properly?
>>
>> Others have already pointed to this# .
>> I just would like to add that you can as well use ~'this in some
>> cases, where your macros generate defns. The advantage is that some
>> editors (like emacs) will show you the parameter vector and that would
>> show a useful name and not this_auto_foobarbaz123456 .
>
> --
> 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 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
