`
user=> (def a (java.io.PushbackReader. (java.io.StringReader. "#?(:clj [1 2])")))
'user/a
user=> (read a)
RuntimeException Conditional read not allowed clojure.lang.Util.runtimeException (Util.java:221)
user=> (read a)
(:clj [1 2])
`
预期的结果是第二个读取时抛出EOF异常。