访问“父范围"在JShell中 [英] Access to "parent scope" in JShell

问题描述

似乎在另一个JShell中创建的JShell对象无权访问父级的JShell范围.例如:

It seems, that JShell object created inside another JShell does not have access to parent's JShell scope. For instance:

jshell> int x = 1;
x ==> 1

jshell> x
x ==> 1

jshell> jdk.jshell.JShell js = jdk.jshell.JShell.create();
js ==> jdk.jshell.JShell@1a052a00

jshell> js.eval("x");
$4 ==> [SnippetEvent(snippet=Snippet:ErroneousKey#1-x,previousStatus=NONEXISTENT,status=REJECTED,isSignatureChange=false,causeSnippetnull)]

jshell> js.eval("int x = 2;");
$5 ==> [SnippetEvent(snippet=Snippet:VariableKey(x)#2-int x = 2;,previousStatus=NONEXISTENT,status=VALID,isSignatureChange=true,causeSnippetnullvalue=2)]

jshell> js.eval("x");
$6 ==> [SnippetEvent(snippet=Snippet:ExpressionKey(x)#3-x,previousStatus=NONEXISTENT,status=VALID,isSignatureChange=true,causeSnippetnullvalue=2)]

是否有可能使父范围对孩子可见?

Is it somehow possible to make parent scope visible to the child one?

推荐答案

根据用于创建的Javadoc ()说:

相当于JShell.builder().build().

Equivalent to JShell.builder().build().

当您遵循 build()，您会发现:

构建一个JShell状态引擎.这是所有JShell功能的切入点.这将创建一个远程过程以执行.因此，关闭返回的实例非常重要.

Build a JShell state engine. This is the entry-point to all JShell functionality. This creates a remote process for execution. It is thus important to close the returned instance.

换句话说:最有可能的是，您正在创建另一个外壳运行的另一个 JVM实例.因此，至少目前为止:没有 child jshell知道其父级的机会.

In other words: most likely, you are creating another JVM instance where that other shell runs. So at least for now: no chances of having a child jshell know about its parent.

(如:我很希望Java的REPL功能可以在将来的某个时候将JShell附加到已经运行的JVM上)

( as in: I seriously hope that this REPL feature of Java will allow at some future point to attach a JShell to an already running JVM )

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