为什么go块内的命名空间会发生变化

Question

(ns myapp.core
  (:require
   [clojure.core.async :refer [>! <! >!! <!! chan go-loop]])
  (:gen-class))

(def this-ns *ns*)

(defn get-ns [c0]
  (go-loop []
    (let [x (<! c0)]
      (println (str "this ns     -> " this-ns))
      (println (str "go block ns -> " *ns*)))
    (recur)))

(defn -main [& args]
  (let [c0 (chan)]
    (get-ns c0)
    (>!! c0 1)))

输出:

this ns     -> myapp.core
go block ns -> user

任何人都可以解释为什么名称空间在go块内是不同的？

Answer 1

我不认为这与此有关core.async.它只是如何*ns*工作 - 它包含当前repls当前命名空间

clojure.core/*ns*
   A clojure.lang.Namespace object representing the current namespace.

换句话说,*ns*取决于您调用的命名空间

例:

; <current-ns>=> <code>

user=> (load-file "yourcode.clj")
#'myapp.core/-main

user=> (myapp.core/-main)
this ns     -> myapp.core
go block ns -> user
true

user=> (in-ns 'myapp.core) ; <-- switching namespace 
#object[clojure.lang.Namespace 0x679e26fe "myapp.core"]

myapp.core=> (-main)
this ns     -> myapp.core
go block ns -> myapp.core
true