如何解决错误：无法读取服务器：远程使用ltk时没有此类变量
我正在修改ltk，因为它提供了运行远程GUI的选项。但是，当尝试使用远程GUI时，遇到本地运行ltk时不会遇到的问题：
(in-package :ltk-user)
(defun add-current-investigation-frame (master)
(let* ((frame (make-instance 'frame :master master :width 100 :height 100))
(topic-label (make-instance 'label :text "Current Investigation" :master frame))
(project-label (make-instance 'entry :text "N/A" :master frame))
(action-button (make-instance 'button
:master frame
:text "new investigation")))
(setf (command action-button) (lambda ()
(format t "test~%")
(let ((next-project (nth (random 3) '("A" "B" "N/A"))))
(setf (text project-label) next-project))))
(pack frame)
(pack topic-label :side :top)
(pack project-label :side :top)
(pack action-button :side :top)))
(defun create-main-view ()
(let ((wrapper-frame (make-instance 'frame :master nil)))
(pack wrapper-frame)
(add-current-investigation-frame wrapper-frame)))
(defun create-remote-view (&optional (port 8888))
(Ltk:with-remote-ltk port ()
(create-main-view)))
(defun create-local-view ()
(with-ltk ()
(create-main-view)))
运行(create-local-view)时，一切正常，条目小部件的内容随机更改。
运行(create-remote-view)时收到错误消息can't read server: no such variable。 为什么会出现此错误，我该如何解决？
我正在使用quicklisp部署的remote.tcl：
#!/usr/bin/wish
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License,or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not,write to the Free Software
# Foundation,Inc.,59 Temple Place,Suite 330,Boston,MA 02111-1307 USA
wm withdraw .
set host localhost
if {[llength $argv] == 2} {
set host [lindex $argv 0]
set port [lindex $argv 1]} else {
set port [lindex $argv 0]}
#puts "connecting to $host $port"
set server [socket $host $port]
set wi [open "|wish" RDWR]
fconfigure $server -blocking 0
fconfigure $wi -blocking 0
fileevent $server readable {set txt [read $server];puts $wi "$txt";flush $wi}
fileevent $wi readable {
if {[eof $wi]} {
close $wi
exit} else {
set txt [read $wi]; puts -nonewline $server $txt;flush $server}}
解决方法
所以我花了一些时间阅读和测试代码，看起来 remote-client.tcl 比 remote.tcl 更有效。使用 ltk-remote.lisp 时，Lisp 端创建一个可以接受多个客户端的服务器，每个客户端都是一个 tcl/tk 解释器。
lisp <=== socket stream ===> [ server socket ]
^
|
(wish interpreter)
lisp 端期望解释器维护一个名为 server 的全局变量。对于本地解释器，这是在 init-wish 中完成的，其中有 set server stdout。在远程希望的情况下，希望解释器自行设置此变量。
remote-client.tcl 就是这种情况，测试应用程序运行良好（例如 ltk-remote::lrtest），只是它添加了一个永远不会被删除的 .status 小部件。应该可以稍微清理一下 remote-client.tcl 脚本。
在 remote.tcl 的情况下，解释器 opens 一对流到另一个 wish 进程：
set wi [open "|wish" RDWR]
它还连接到服务器（变量 server），并将输入从服务器复制到希望进程。不幸的是，嵌入的愿望过程没有定义一个 server 变量：
lisp <=== socket stream ===> [ server socket ]
^
|
(wish interpreter 1)
"server" variable
|
"wi" variable
^
| pipe connection
v
(wish interpreter 2)
no "server" variable
但是，如果您将 server 设置为 stdout，如另一个答案中所述，则此分配将在第二个 Wish 解释器中进行评估。输出被发送回第一个 Wish 解释器，后者将答案复制回 lisp 服务器。
我没有通过另一个 Wish 解释器，而是使用不添加任何小部件的修改后的 remote-client.tcl 在本地进行测试：
package require Tk
set host localhost
set port 19790
set server ""
if {[llength $argv] > 0} {
set host [lindex $argv 0]
}
if {[llength $argv] > 1} {
set port [lindex $argv 1]
}
if {[catch {global server; global host; global port; set server [socket $host $port]}]} {
tk_messageBox -icon error -type ok -title "Connection failed!" -message "Cannot connect to server $host port $port."
exit
}
fconfigure $server -blocking 0 -translation binary -encoding utf-8
fileevent $server readable [list sread $server]
set buffer ""
proc getcount {s} {
if {[regexp {^\s*(\d+) } $s match num]} {
return $num
}
}
proc getstring {s} {
if {[regexp {^\s*(\d+) } $s match]} {
return [string range $s [string length $match] end]
}
}
proc process_buffer {} {
global buffer
global server
set count [getcount $buffer]
set tmp_buf [getstring $buffer]
while {($count > 0) && ([string length $tmp_buf] >= $count)} {
set cmd [string range $tmp_buf 0 $count]
set buffer [string range $tmp_buf [expr $count+1] end]
if {[catch $cmd result]>0} {
tk_messageBox -icon error -type ok -title "Error!" -message $result
puts $server "(error: \"$result\")"
flush $server
close $server
exit
}
set count [getcount $buffer]
set tmp_buf [getstring $buffer]
}
}
proc sread {server} {
global buffer
if {[eof $server]} {
tk_messageBox -icon info -type ok -title "Connection closed" -message "The connection has been closed by the server."
close $server
exit
} else {
set txt [read $server];
set buffer "$buffer$txt"
process_buffer
}
}
这是一个初步的答案，因为我不完全确定此修复程序不会破坏任何内容。我将在以后更新此答案，以报告遇到的问题。但是现在这可以解决问题。
在ltk.lisp中有一个名为init-wish的函数，该函数需要另外一行(send-wish "set server stdout")
(defun init-wish ()
(send-lazy
;; print string readable,escaping all " and \
;; proc esc {s} {puts "\"[regsub {"} [regsub {\\} $s {\\\\}] {\"}]\""}
;(send-wish "proc esc {s} {puts \"\\\"[regsub -all {\"} [regsub -all {\\\\} $s {\\\\\\\\}] {\\\"}]\\\"\"} ")
;(send-wish "proc escape {s} {return [regsub -all {\"} [regsub -all {\\\\} $s {\\\\\\\\}] {\\\"}]} ")
(send-wish "package require Tk")
;;; PUT MISSING LINE HERE
(send-wish "set server stdout")
;;; PUT MISSING LINE HERE
(flush-wish)
#+:tk84
(send-wish "catch {package require Ttk}")
#-:tk84
(send-wish "if {[catch {package require Ttk} err]} {tk_messageBox -icon error -type ok -message \"$err\"}")
(send-wish "proc debug { msg } {
global server
puts $server \"(:debug \\\"[escape $msg]\\\")\"
flush $server
} ")
; more code ....
))
说明：：该功能似乎可以设置愿望界面和操作（通过在remote.tcl中插入图片来确认）。但是，可以看到server在所有proc中都被引用，但是如果我们认为所有这些声明都在它们自己的名称空间中，则永远不会声明它。因此，必须定义丢失的服务器。由于所有输出都被fileevent $wi ...读取，然后进一步传递，因此将server定义为stdout似乎是最明智的。
这似乎可行，但是我不知道这是否会破坏其他内容
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