Clojurians Log v2

Not really. You can use m/app as an escape hatch to reduce / aggregate data.

I hear meander zeta will be able to handle this situation (friendly poke @noprompt)

but i have no idea how to do that even with m/app

Something like this:

(m/rewrites data                                                                                                                                        
     (m/$ {:connections (m/some {:active !a :created !c})})                                                                                                
     {:active (m/app (fn[as] (reduce + as)) [!a ...])}))

Notice the use of ! instead of ?

The ! symbol indicates a memory variable which will collect all of the values. [!a …] expands the memory variable to a vector which is then passed into the function

Does that make sense?

@markaddleman thank you, for explanation!

am trying that:

(let [sum #(reduce + 0 %)]                                                                                                                                      
     #(m/rewrites %                                                                                                                                                
         (m/$ {:connections (m/some {:active !a :created !b})})                                                                                                     
             {:active (m/app sum [!a ...])                                                                                                                              
              :created (m/app sum [!b ...])})))

it returns array of maps instead of single map

I think you want to use m/rewrite instead of m/rewrites

but i need to aggregate all {:active !a :created !b}

inside that data structure

Thank you for explaining.

The m/app sum… operation is applied at each match.

You want to sum over all matches. Is that correct?

that way it works as expected:

#(apply merge-with +                                                                                                                                            
     (m/rewrites %                                                                                                                                           
          (m/$ {:connections (m/some {:active ?a :created ?c})})                                                                                                
          {:active ?a :created ?c}))

"You want to sum over all matches. Is that correct?" yes

Yes, that makes sense. I apologize - I assumed a different datastructure

np )

To explain: The scope of a memory variable is each match. In your case, the memory variable is reset at each {:activity _ :created _} so my solution does not work for you

thats clear, thanks! then i will go with apply merge-with +