在 Guile 中对列表进行排序时项目消失
Items disapear when `sort!`'ing a list in Guile
在字符串列表上调用 sort! 后，我似乎遇到了项目消失的情况：
（我从我正在处理的 Autogen 模板中派生了这段代码。）
(use-modules (ice-9 pretty-print))
(let ((files '("log4cplus/socketappender.h"
"log4cplus/qt4debugappender.h"
"log4cplus/nteventlogappender.h"
"log4cplus/ndc.h"
"log4cplus/msttsappender.h"
"log4cplus/mdc.h"
"log4cplus/loglevel.h"
"log4cplus/loggingmacros.h"
"log4cplus/logger.h"
"log4cplus/log4judpappender.h"
"log4cplus/log4cplus.h"
"log4cplus/layout.h"
"log4cplus/hierarchylocker.h"
"log4cplus/hierarchy.h"
"log4cplus/fstreams.h"
"log4cplus/clogger.h"
"log4cplus/asyncappender.h"
"log4cplus/version.h"
"log4cplus/tstring.h"
"log4cplus/qt5debugappender.h"
"log4cplus/nullappender.h"
"log4cplus/fileappender.h"
"log4cplus/consoleappender.h"
"log4cplus/clfsappender.h"
"log4cplus/appender.h"
"log4cplus/win32debugappender.h"
"log4cplus/win32consoleappender.h"
"log4cplus/tracelogger.h"
"log4cplus/tchar.h"
"log4cplus/syslogappender.h"
"log4cplus/initializer.h"
"log4cplus/configurator.h"
"log4cplus/config.hxx"
"log4cplus/thread/threads.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/streams.h"
"log4cplus/internal/socket.h"
"log4cplus/internal/internal.h"
"log4cplus/internal/env.h"
"log4cplus/internal/cygwin-win32.h"
"log4cplus/helpers/thread-config.h"
"log4cplus/helpers/socket.h"
"log4cplus/helpers/pointer.h"
"log4cplus/helpers/lockfile.h"
"log4cplus/helpers/connectorthread.h"
"log4cplus/helpers/timehelper.h"
"log4cplus/helpers/stringhelper.h"
"log4cplus/helpers/socketbuffer.h"
"log4cplus/helpers/snprintf.h"
"log4cplus/helpers/queue.h"
"log4cplus/helpers/property.h"
"log4cplus/helpers/loglog.h"
"log4cplus/helpers/fileinfo.h"
"log4cplus/helpers/appenderattachableimpl.h"
"log4cplus/config/windowsh-inc.h"
"log4cplus/config/win32.h"
"log4cplus/config/macosx.h"
"log4cplus/boost/deviceappender.hxx")))
(begin
;; Add the generated header as it will not be found by file search.
(append! files (list "log4cplus/config/defines.hxx"))
(display "before sort:\n")
(pretty-print files)
(sort! files string<?)
(display "after sort:\n")
(pretty-print files)))
我看到的输出是这样的：
before sort:
("log4cplus/socketappender.h"
"log4cplus/qt4debugappender.h"
"log4cplus/nteventlogappender.h"
"log4cplus/ndc.h"
"log4cplus/msttsappender.h"
"log4cplus/mdc.h"
"log4cplus/loglevel.h"
"log4cplus/loggingmacros.h"
"log4cplus/logger.h"
"log4cplus/log4judpappender.h"
"log4cplus/log4cplus.h"
"log4cplus/layout.h"
"log4cplus/hierarchylocker.h"
"log4cplus/hierarchy.h"
"log4cplus/fstreams.h"
"log4cplus/clogger.h"
"log4cplus/asyncappender.h"
"log4cplus/version.h"
"log4cplus/tstring.h"
"log4cplus/qt5debugappender.h"
"log4cplus/nullappender.h"
"log4cplus/fileappender.h"
"log4cplus/consoleappender.h"
"log4cplus/clfsappender.h"
"log4cplus/appender.h"
"log4cplus/win32debugappender.h"
"log4cplus/win32consoleappender.h"
"log4cplus/tracelogger.h"
"log4cplus/tchar.h"
"log4cplus/syslogappender.h"
"log4cplus/initializer.h"
"log4cplus/configurator.h"
"log4cplus/config.hxx"
"log4cplus/thread/threads.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/streams.h"
"log4cplus/internal/socket.h"
"log4cplus/internal/internal.h"
"log4cplus/internal/env.h"
"log4cplus/internal/cygwin-win32.h"
"log4cplus/helpers/thread-config.h"
"log4cplus/helpers/socket.h"
"log4cplus/helpers/pointer.h"
"log4cplus/helpers/lockfile.h"
"log4cplus/helpers/connectorthread.h"
"log4cplus/helpers/timehelper.h"
"log4cplus/helpers/stringhelper.h"
"log4cplus/helpers/socketbuffer.h"
"log4cplus/helpers/snprintf.h"
"log4cplus/helpers/queue.h"
"log4cplus/helpers/property.h"
"log4cplus/helpers/loglog.h"
"log4cplus/helpers/fileinfo.h"
"log4cplus/helpers/appenderattachableimpl.h"
"log4cplus/config/windowsh-inc.h"
"log4cplus/config/win32.h"
"log4cplus/config/macosx.h"
"log4cplus/boost/deviceappender.hxx"
"log4cplus/config/defines.hxx")
after sort:
("log4cplus/qt4debugappender.h"
"log4cplus/qt5debugappender.h"
"log4cplus/socketappender.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/streams.h"
"log4cplus/syslogappender.h"
"log4cplus/tchar.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/threads.h"
"log4cplus/tracelogger.h"
"log4cplus/tstring.h"
"log4cplus/version.h"
"log4cplus/win32consoleappender.h"
"log4cplus/win32debugappender.h")
如您所见，排序后的列表丢失了一半的项目。
我在 Scheme 源代码中做错了什么？
更新
因此，通过反复试验，我偶然发现了似乎可以解决的问题。当我将 (sort! files string-ci<?) 更改为 (set! files (sort! files string<?)) 时，我得到了想要的结果。但是我很困惑，为什么就地排序没有像我预期的那样工作。
来自手册：
Sort the sequence items, which may be a list or a vector. less is used for comparing the sequence elements. The sorting is destructive, that means that the input sequence is modified to produce the sorted result. This is not a stable sort.
https://www.gnu.org/software/guile/manual/html_node/Sorting.html
该程序具有破坏性，但不保证输入序列可用。所以你总是需要使用返回值作为排序序列。
在字符串列表上调用 sort! 后，我似乎遇到了项目消失的情况：
（我从我正在处理的 Autogen 模板中派生了这段代码。）
(use-modules (ice-9 pretty-print))
(let ((files '("log4cplus/socketappender.h"
"log4cplus/qt4debugappender.h"
"log4cplus/nteventlogappender.h"
"log4cplus/ndc.h"
"log4cplus/msttsappender.h"
"log4cplus/mdc.h"
"log4cplus/loglevel.h"
"log4cplus/loggingmacros.h"
"log4cplus/logger.h"
"log4cplus/log4judpappender.h"
"log4cplus/log4cplus.h"
"log4cplus/layout.h"
"log4cplus/hierarchylocker.h"
"log4cplus/hierarchy.h"
"log4cplus/fstreams.h"
"log4cplus/clogger.h"
"log4cplus/asyncappender.h"
"log4cplus/version.h"
"log4cplus/tstring.h"
"log4cplus/qt5debugappender.h"
"log4cplus/nullappender.h"
"log4cplus/fileappender.h"
"log4cplus/consoleappender.h"
"log4cplus/clfsappender.h"
"log4cplus/appender.h"
"log4cplus/win32debugappender.h"
"log4cplus/win32consoleappender.h"
"log4cplus/tracelogger.h"
"log4cplus/tchar.h"
"log4cplus/syslogappender.h"
"log4cplus/initializer.h"
"log4cplus/configurator.h"
"log4cplus/config.hxx"
"log4cplus/thread/threads.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/streams.h"
"log4cplus/internal/socket.h"
"log4cplus/internal/internal.h"
"log4cplus/internal/env.h"
"log4cplus/internal/cygwin-win32.h"
"log4cplus/helpers/thread-config.h"
"log4cplus/helpers/socket.h"
"log4cplus/helpers/pointer.h"
"log4cplus/helpers/lockfile.h"
"log4cplus/helpers/connectorthread.h"
"log4cplus/helpers/timehelper.h"
"log4cplus/helpers/stringhelper.h"
"log4cplus/helpers/socketbuffer.h"
"log4cplus/helpers/snprintf.h"
"log4cplus/helpers/queue.h"
"log4cplus/helpers/property.h"
"log4cplus/helpers/loglog.h"
"log4cplus/helpers/fileinfo.h"
"log4cplus/helpers/appenderattachableimpl.h"
"log4cplus/config/windowsh-inc.h"
"log4cplus/config/win32.h"
"log4cplus/config/macosx.h"
"log4cplus/boost/deviceappender.hxx")))
(begin
;; Add the generated header as it will not be found by file search.
(append! files (list "log4cplus/config/defines.hxx"))
(display "before sort:\n")
(pretty-print files)
(sort! files string<?)
(display "after sort:\n")
(pretty-print files)))
我看到的输出是这样的：
before sort:
("log4cplus/socketappender.h"
"log4cplus/qt4debugappender.h"
"log4cplus/nteventlogappender.h"
"log4cplus/ndc.h"
"log4cplus/msttsappender.h"
"log4cplus/mdc.h"
"log4cplus/loglevel.h"
"log4cplus/loggingmacros.h"
"log4cplus/logger.h"
"log4cplus/log4judpappender.h"
"log4cplus/log4cplus.h"
"log4cplus/layout.h"
"log4cplus/hierarchylocker.h"
"log4cplus/hierarchy.h"
"log4cplus/fstreams.h"
"log4cplus/clogger.h"
"log4cplus/asyncappender.h"
"log4cplus/version.h"
"log4cplus/tstring.h"
"log4cplus/qt5debugappender.h"
"log4cplus/nullappender.h"
"log4cplus/fileappender.h"
"log4cplus/consoleappender.h"
"log4cplus/clfsappender.h"
"log4cplus/appender.h"
"log4cplus/win32debugappender.h"
"log4cplus/win32consoleappender.h"
"log4cplus/tracelogger.h"
"log4cplus/tchar.h"
"log4cplus/syslogappender.h"
"log4cplus/initializer.h"
"log4cplus/configurator.h"
"log4cplus/config.hxx"
"log4cplus/thread/threads.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/streams.h"
"log4cplus/internal/socket.h"
"log4cplus/internal/internal.h"
"log4cplus/internal/env.h"
"log4cplus/internal/cygwin-win32.h"
"log4cplus/helpers/thread-config.h"
"log4cplus/helpers/socket.h"
"log4cplus/helpers/pointer.h"
"log4cplus/helpers/lockfile.h"
"log4cplus/helpers/connectorthread.h"
"log4cplus/helpers/timehelper.h"
"log4cplus/helpers/stringhelper.h"
"log4cplus/helpers/socketbuffer.h"
"log4cplus/helpers/snprintf.h"
"log4cplus/helpers/queue.h"
"log4cplus/helpers/property.h"
"log4cplus/helpers/loglog.h"
"log4cplus/helpers/fileinfo.h"
"log4cplus/helpers/appenderattachableimpl.h"
"log4cplus/config/windowsh-inc.h"
"log4cplus/config/win32.h"
"log4cplus/config/macosx.h"
"log4cplus/boost/deviceappender.hxx"
"log4cplus/config/defines.hxx")
after sort:
("log4cplus/qt4debugappender.h"
"log4cplus/qt5debugappender.h"
"log4cplus/socketappender.h"
"log4cplus/spi/appenderattachable.h"
"log4cplus/spi/factory.h"
"log4cplus/spi/filter.h"
"log4cplus/spi/loggerfactory.h"
"log4cplus/spi/loggerimpl.h"
"log4cplus/spi/loggingevent.h"
"log4cplus/spi/objectregistry.h"
"log4cplus/spi/rootlogger.h"
"log4cplus/streams.h"
"log4cplus/syslogappender.h"
"log4cplus/tchar.h"
"log4cplus/thread/impl/syncprims-cxx11.h"
"log4cplus/thread/impl/syncprims-impl.h"
"log4cplus/thread/impl/syncprims-pmsm.h"
"log4cplus/thread/impl/threads-impl.h"
"log4cplus/thread/impl/tls.h"
"log4cplus/thread/syncprims-pub-impl.h"
"log4cplus/thread/syncprims.h"
"log4cplus/thread/threads.h"
"log4cplus/tracelogger.h"
"log4cplus/tstring.h"
"log4cplus/version.h"
"log4cplus/win32consoleappender.h"
"log4cplus/win32debugappender.h")
如您所见，排序后的列表丢失了一半的项目。
我在 Scheme 源代码中做错了什么？
更新
因此，通过反复试验，我偶然发现了似乎可以解决的问题。当我将 (sort! files string-ci<?) 更改为 (set! files (sort! files string<?)) 时，我得到了想要的结果。但是我很困惑，为什么就地排序没有像我预期的那样工作。
来自手册：
Sort the sequence items, which may be a list or a vector. less is used for comparing the sequence elements. The sorting is destructive, that means that the input sequence is modified to produce the sorted result. This is not a stable sort.
https://www.gnu.org/software/guile/manual/html_node/Sorting.html
该程序具有破坏性，但不保证输入序列可用。所以你总是需要使用返回值作为排序序列。