alt Hacker NewsThis is beside the point, and I'm being pedantic, but the unix pipeline and the clojure expression don't quite do the same thing.
The clojure expression reads the entire file into memory first, and then operates on that memory representation.
The pipeline processes the input in chunks. The two `sort`s might read the entire contents into memory, but an implementation like GNU sort will instead, for large inputs, create temporary files for sections of the input and then merge sort them to the output.
You could make clojure do the same thing, but it might not be as "simple" as the pipeline.
This bothered me too. The author even said:
> Now, let's say we want to make a small change: show the output in the original file order. In Clojure, this is fairly straightforward: store an ordered sequence of the words in word_seq, store a map from each word to its frequency in freq_map, iterate over the sequence, and look up each word in the map:
Emphasis on just "storing" something. The author seems to not understand that this change makes the solutions categorically different.
It's a little like critiquing the efficiency of moving a piano up a stairwell by saying why didn't they just use a crane via the window? Using a crane isn't a better way of getting a piano up the stairwell.