Clojure macro that will conserve associative map order

Question

To preface, I am on Windows 7 (64-bit), running Java version 6 (update 33) using clooj as my IDE. I have not tried to reproduce my problem in any other system. I am experien

Answer 1

The problem as stated is not soluble. Maps are defined to have no order; any order you see in array-map is coincidental. If you require that your macro receive a map, you have already lost the information you desire.

Answer 2

you can make your map with array-map

user> (map vec (array-map 1 2 3 4 5 6))
([1 2] [3 4] [5 6])

or with a larger map

user> (map vec (apply array-map (range 50)))
([0 1] [2 3] [4 5] [6 7] [8 9] [10 11] [12 13] [14 15] [16 17] [18 19] [20 21] [22 23] [24 25] [26 27] [28 29] [30 31] [32 33] [34 35] [36 37] [38 39] [40 41] [42 43] [44 45] [46 47] [48 49])

as a bonus you can avoid using a macro, which is useful because macros are not first-class and don't compose well*

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a note on your first comment from the documentation on array map

 Note that an array map will only maintain sort order when un-'modified'. 
 Subsequent assoc-ing will eventually cause it to 'become' a hash-map.

If you find yourself depending on the order of keys in your maps you may want to consider if a sorted-map will get you what you need. It will scale better than an array-map. In the above example the output is the same:

(map vec (apply sorted-map (range 5000)))
[0 1] [2 3] ... [4998 4999]

*this is my opinion

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EDIT:

a time comparason of sorted-map vs. array-map

user> (time (dorun (map vec (apply sorted-map (range 500000)))))
"Elapsed time: 391.520491 msecs"
nil
user> (time (dorun (map vec (apply array-map (range 500000)))))
"Elapsed time: 674517.821669 msecs"