I wonder why the definline didn't act like a function?
=> (defn pred-transform [obj pred tf]
(if (pred obj) obj
(tf obj)))
#'cgws.notcore/pred-transform
=> (pred-transform (println 1) #(not (nil? %)) #(println % "."))
1
nil .
nil
=> (pred-transform (println 1) nil? #(println % "."))
1
nil
=> (fn? pred-transform)
true
=> (definline pred-transform [obj pred tf]
`(let [o# ~obj]
(if (~pred o#) o#
(~tf o#))))
#'cgws.notcore/pred-transform
=> (fn? pred-transform)
true
On Sat, May 25, 2013 at 3:08 PM, atkaaz <atk...@gmail.com> wrote:
> like:
> => (definline pred-transform [obj pred tf]
> `(let [o# ~obj]
> (if (~pred o#) o#
> (~tf o#))))
> #'cgws.notcore/pred-transform
>
> => (pred-transform (println 1) nil? #(println % "."))
> 1
> nil
> => (pred-transform (println 1) #(not (nil? %)) #(println % "."))
> 1
> nil .
> nil
>
>
> On Sat, May 25, 2013 at 3:07 PM, atkaaz <atk...@gmail.com> wrote:
>
>> in which case it does get evaluated twice if form:
>> => (pred-transform (println 1) #(not (nil? %)) #(println % "."))
>> 1
>> 1
>> nil .
>> nil
>>
>> => (pred-transform (println 1) nil? #(println % "."))
>> 1
>> 1
>> nil
>>
>> so maybe a let + gensym would be in order?
>>
>>
>>
>> On Sat, May 25, 2013 at 3:04 PM, atkaaz <atk...@gmail.com> wrote:
>>
>>> 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?
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>>>>>
>>>>
>>>>
>>>
>>
>
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