[roryokane]

Fixed link to that style guide entry: https://guide.clojure.style/#opt-commas-in-map-literals

Per that style guide, the above map should be formatted like this:

  {:a 1
   2 :bar
   [1 2 3] :baz}

Most maps written in EDN have keys of a consistent type. A map whose keys are consistently keywords would look like this when formatted:

  {:a 1
   :bar "https://example.com/"
   :baz [1 2 3]}

Or like this, when condensed to one line:

  {:a 1, :bar "https://example.com/", :baz [1 2 3]}

The first map had keys of three different types: keyword `:a`, integer `2`, and vector `[1 2 3]`. Why would one want a format that supports maps with mixed-type keys? As a contrived example, mixed-type keys let you define a sparse 2D tile-based map for a game that is indexed by x and y coordinates:

  {:default {:type :grass}
   [0 1] {:type :npc-rival}
   [2 3] {:type :wall}
   [2 4] {:type :wall}
   [100 -5] {:type :treasure, :contents :sword-of-slaying}}

HN comment formatting help: https://news.ycombinator.com/formatdoc. I indented the above code by two spaces.