[CLJS-1376|http://dev.clojure.org/jira/browse/CLJS-1376) wanted to bring printing parity with Clojure 1.7.0.
There are two problems:
1) Atom and Volatile contain extra space between #object and "[" (that differs from Clojure 1.7.0)
2) Atom and Volatile printing was inconsistent with #object printing in pr-writer-impl (in goog/isFunction and :else branches) - there we have no space
I have introduced a function which handles printing object tags consistently without space. Also I have broken writing content into writer into logical tokens for easier cljs-devtools implementation.
Exact printing behaviour is quite important for me when implementing alternative pr-writer-impl for cljs-devtools. For most cases I call original pr-writer-impl and then post-process its output to enhance its presentation in DevTools console:
In other cases like Atom or Volatile, I would like to easily detect "#object" as first token written into writer and provide better visual clues. I find printing "#object [...]" confusing for more complex data situations. Square brackets resemble vectors and may confuse clarity. Instead I will use color-coding or another form of visual styling to mark object instances and their boundaries. But for this I want to have nice token stream "#object" "[" ... "]" without having to use regexps.