错误：无法读取服务器：远程使用 ltk 时没有这样的变量

Question

我正在修改ltk，因为它提供了运行远程 GUI 的选项。但是，在尝试使用远程 GUI 时，我遇到了在本地运行 ltk 时没有遇到的问题：

(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，并且入口小部件的内容随机变化。

运行(create-remote-view) 时，我收到错误消息can't read server: no such variable。 为什么会出现此错误，我该如何解决？

我使用的是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}}

Answer 1

所以我花了一些时间阅读和测试代码，似乎它与remote-client.tcl 一起工作比remote.tcl 更好。当使用ltk-remote.lisp 时，Lisp 端会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 端希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。在远程愿望的情况下，希望解释器自己设置这个变量。

remote-client.tcl 就是这种情况，测试应用程序运行良好（例如ltk-remote::lrtest），除了它添加了一个永远不会删除的.status 小部件。应该可以清理一下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wish 进程。不幸的是，嵌入式愿望过程没有定义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愿望解释器中进行评估。输出被发送回第一个愿望解释器，它将答案复制回 lisp 服务器。

我没有通过另一个愿望解释器，而是使用修改后的remote-client.tcl 进行本地测试，不添加任何小部件：

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
    }
}

Answer 2

这是一个初步答案，因为我不完全确定此修复不会破坏任何东西。我将来会更新此答案以报告遇到的问题。但现在这解决了这个问题。

在ltk.lisp 中有一个名为init-wish 的函数，它需要额外的一行(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 ....
))

解释：该函数似乎设置了wish界面和动作（通过在remote.tcl中插入打印来确认）。然而，正如人们所看到的，server 在所有过程中都被引用，但如果我们认为所有这些声明都在它们自己的命名空间中，它就永远不会被声明。因此，必须定义丢失的服务器。由于所有输出都由fileevent $wi ... 读取，然后进一步传递，将server 定义为stdout 似乎是最明智的。

它似乎有效，但我不知道这是否会破坏其他东西