Shouldn't it be like:
(definline pred-transform [obj pred tf]
`(if (~pred ~obj) ~obj
(~tf ~obj)))
=> (pred-transform 1 #(not (nil? %)) println)
1
=> (pred-transform 1 nil? println)
1
nil
On Sat, May 25, 2013 at 2:55 PM, atkaaz <atk...@gmail.com> wrote:
> just wondering if obj is a form does it get evaluated twice?
>
>
> On Sat, May 25, 2013 at 2:51 PM, Jim - FooBar(); <jimpil1...@gmail.com>wrote:
>
>> no need for macros... :)
>>
>> (definline safe-assoc [m k v]
>> `(if (contains? ~m ~k) ~m
>> (assoc ~m ~k ~v)))
>>
>> (definline pred-transform [obj pred tf]
>> `(if ~(pred obj) ~obj
>> ~(tf obj)))
>>
>> Jim
>>
>>
>>
>> On 25/05/13 12:44, atkaaz wrote:
>>
>> may I see the macro for the latter, if you decide to go that way ? thx
>>
>>
>> On Sat, May 25, 2013 at 2:24 PM, Steven Degutis <sbdegu...@gmail.com>wrote:
>>
>>> There are two patterns I find in my code that I'm still unhappy with but
>>> I don't know how to clean up.
>>>
>>> The first is: (if (:attr obj) obj (assoc obj :attr something))
>>>
>>> I'm basically saying, give this hash-map an attribute if it doesn't
>>> already have it. And just return the thing with an attribute, regardless if
>>> I had to add it or not.
>>>
>>> This version is ugly because it repeats obj three times. I could write
>>> my own macro to de-duplicate it, but I avoid doing that when I can because
>>> there's usually a better built-in solution that I just don't know about yet.
>>>
>>> The second is like it: (if (some-test obj) obj (some-transformation
>>> obj))
>>>
>>> In this one, I just want to return the object, but maybe transform it
>>> first. But the reference to obj happens three times! Still feels like it
>>> could be cleaned up.
>>>
>>> Any thoughts on how to clean these up?
>>> --
>>> --
>>> 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/groups/opt_out.
>>>
>>>
>>>
>>
>> --
>> --
>> 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/groups/opt_out.
>>
>>
>>
>>
>> --
>> --
>> 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/groups/opt_out.
>>
>>
>>
>
>
--
--
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/groups/opt_out.
