我在调试我的 Clojure 程序 Infocard Workbench 时遇到了一个真正意外的错误：A (swank.core/break)in a function 导致 CLI 窗口出错，导致执行中止，即使(-main)Clojure/Swank REPL 调用了正在运行的程序 。当我注释掉 break 语句时，程序运行正常。为什么我从创建 REPL 的 leiningen 进程而不是 SWANK REPL 本身收到错误？
万一重要，该程序使用以下库： Seesaw (Swing UI)；Piccolo2D（Swing 2D 图形）；Sedna（具有 XQuery 访问权限的 XML 数据库）。
堆栈跟踪如下。以“GW COMMENT >>>”开头的行是我添加的注释行，不是跟踪的一部分。
--- BEGIN cli window output ---
generic-sh-d: field-text is
GW COMMENT >>> Here, I'm in the menu handler for a file-open operation (Seesaw)
shortname-hdlr: filename is t
shortname-handler, inside 2nd 'let'
reached display-file-icards
GW COMMENT >>> Here, I'm printing out actual XQueries to the Sedna database.
declare default element namespace 'http://infoml.org/infomlFile'; for $base in doc('t', 'daily')/infomlFile/infoml[position() != 1] return $base/@cardId/string()
unified-load, before
declare default element namespace 'http://infoml.org/infomlFile';
for $base in collection('daily')/infomlFile/infoml[@cardId = 'gw667_110929221548137']
return ($base/data/title/string(), $base/data/content/string(), $base/selectors/tag/string())
GW COMMENT >>> More XQueries; the "AFTER" indicates the query completed w/o crashing
unified-load, AFTER
unified-load, before
declare default element namespace 'http://infoml.org/infomlFile';
for $base in collection('daily')/infomlFile/infoml[@cardId = 'gw667_110929221638791']
return ($base/data/title/string(), $base/data/content/string(), $base/selectors/tag/string())
unified-load, AFTER
GW COMMENT >>> omitted several before/AFTER pairs; all were successful
GW COMMENT >>> Here's the actual error; note the namespace, swank.core.connection
Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException: Var swank.core.connection/*current-connection* is unbound.
at clojure.lang.Var.deref(Var.java:142)
at clojure.lang.Var.get(Var.java:133)
at swank.core$send_to_emacs.invoke(core.clj:76)
at swank.core$sldb_loop.invoke(core.clj:203)
at swank.core$invoke_debugger.invoke(core.clj:214)
at infwb.sedna$display_file_icards.invoke(NO_SOURCE_FILE:1)
at infwb.misc_dialogs$shortname_handler.invoke(misc_dialogs.clj:76)
at infwb.core$make_app$open_h__3812.invoke(core.clj:37)
at seesaw.action$action$fn__386.invoke(action.clj:74)
at seesaw.action.proxy$javax.swing.AbstractAction$0.actionPerformed(Unknown Source)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2028)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2351)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
unified-load, AFTER
display-file-icards: exited let-bindings
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at javax.swing.AbstractButton.doClick(AbstractButton.java:389)
at com.apple.laf.ScreenMenuItem.actionPerformed(ScreenMenuItem.java:95)
at java.awt.MenuItem.processActionEvent(MenuItem.java:627)
at java.awt.MenuItem.processEvent(MenuItem.java:586)
at java.awt.MenuComponent.dispatchEventImpl(MenuComponent.java:337)
at java.awt.MenuComponent.dispatchEvent(MenuComponent.java:325)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:682)
at java.awt.EventQueue.access$000(EventQueue.java:85)
at java.awt.EventQueue$1.run(EventQueue.java:638)
at java.awt.EventQueue$1.run(EventQueue.java:636)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
at java.awt.EventQueue$2.run(EventQueue.java:652)
at java.awt.EventQueue$2.run(EventQueue.java:650)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:649)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
--- END cli window output ---
这是包含该break语句的函数：
(defn display-file-icards ; NEW API 111002
""
[shortname coll-name layer-name]
(println "reached display-file-icards")
(let [icard-seq (get-file-icards shortname coll-name)
slip-seq (doall (map unified-load icard-seq))]
(println "display-file-icards: exited let-bindings")
(swank.core/break)
(display-seq slip-seq layer-name)))
回顾错误信息：
Exception in thread "AWT-EventQueue-0" java.lang.IllegalStateException:
Var swank.core.connection/*current-connection* is unbound.
我看不出*current-connection*与 Swankbreak消息的执行有何关联。我的程序确实有一个名为 的符号*current-connection*，但它位于命名空间infwb.sedna中，这与我的 REPL 运行的命名空间不同，即infwb.core.
如果有人想要，我可以发布更多 Clojure 源代码。感谢您花时间考虑这个问题。