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Turn off * print-namespace-maps * in repl

With Clojure 1.9-beta2, the reader and writer now support compact syntax for maps . The syntax allows you to avoid repeating the namespace in the case when all the keys are qualified keywords with the same namespace:

> (pr-str {:a/foo 1 :a/bar 2})
"#:a{:foo 1, :bar 2}"

This causes problems when sending such a serialized map to the Clojure 1.8 process: the old reader working there will not be able to read it and issue it java.lang.RuntimeException: Reader tag must be a symbol.

Fortunately, the printer does this only when the dynamic variable is *print-namespace-maps*true and false by default, so my application continues to work in production. However, the REPL sets it to true, so when I work in the REPL and do something that eventually sends a request to the Clojure 1.8 service, it crashes. How can I disable the new syntax in REPL as well?

I thought that maybe I could just (set! *print-namespace-maps* false)add in my repl or add {:user {:repl-options {:init (set! *print-namespace-maps* false)}}}to my ~ / .lein / profiles.clj, but that doesn't seem to work. I think the reason may be that the REPL uses bindingto create local stream bindings for a group of variables, including this one, and set! doesn't work for local variable bindings .

+5
1

print-method , .

(defmethod print-method clojure.lang.IPersistentMap [m, ^java.io.Writer w]
  (#'clojure.core/print-meta m w)
  (#'clojure.core/print-map m #'clojure.core/pr-on w))
0

Source: https://habr.com/ru/post/1687902/

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