terminal - 我可以在 Unix expect 中运行 jshell 吗？

Question

我想使用 expect 重定向 jshell 输入，这样我就可以在录制的演示中模拟输入。但是，尽管我可以从 expect 脚本中生成一个 jshell 进程，它也可以识别 jshell 提示符，但之后什么都不起作用。 expect 输出看起来像控制序列的内容，例如 ^[[24;9R，但我没有看到 jshell 的任何输出。不同的终端类型产生不同的字符序列，但它们都不起作用。此行为在 Ubuntu 和 Mac OS 上的 expect 之间是一致的。欢迎就如何调查此问题提出任何建议。 expect -d 没有帮助。

这是我要模拟的 jshell session 的记录

$ jshell
|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

jshell> 3
$1 ==> 3

jshell> 

这是我认为应该执行的脚本:

#!/usr/bin/expect -f
spawn jshell
expect jshell>
send "3\r"
expect jshell>

当我运行该脚本时(在 Mac OS 10.11.6 上，但我在 Ubuntu 上得到的结果非常相似)，我看到了这个输出

spawn jshell
|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

jshell> ^[[24;9R

然后 expect 超时，最后一行输出被 shell 提示符覆盖(因此看起来好像在超时时写入了更多控制字符)。

在脚本第 1 行中将 -d 添加到 expect 的标志中会产生以下输出:

expect version 5.45
argv[0] = /usr/bin/expect  argv[1] = -d  argv[2] = -f  argv[3] = ./expectscript
set argc 0
set argv0 "./expectscript"
set argv ""
executing commands from command file ./expectscript
spawn jshell
parent: waiting for sync byte
parent: telling child to go ahead
parent: now unsynchronized from child
spawn: returns {19712}

expect: does "" (spawn_id exp8) match glob pattern "jshell>"? no
|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

expect: does "|  Welcome to JShell -- Version 9.0.1\r\n|  For an introduction type: /help intro\r\n" (spawn_id exp8) match glob pattern "jshell>"? no

jshell>
expect: does "|  Welcome to JShell -- Version 9.0.1\r\n|  For an introduction type: /help intro\r\n\r\njshell> " (spawn_id exp8) match glob pattern "jshell>"? yes 
expect: set expect_out(0,string) "|  Welcome to JShell -- Version 9.0.1\r\n|  For an introduction type: /help intro\r\n\r\njshell> "
expect: set expect_out(spawn_id) "exp8"
expect: set expect_out(buffer) "|  Welcome to JShell -- Version 9.0.1\r\n|  For an introduction type: /help intro\r\n\r\njshell> "
send: sending "3\r" to { exp8 }

expect: does "" (spawn_id exp8) match glob pattern "jshell>"? no

expect: does "\u001b[6n" (spawn_id exp8) match glob pattern "jshell>"? no
^[[32;1Rexpect: timed out

Answer 1

设法使其工作(在带有 jshell 9.0 和 Expect 5.45 的 Debian 9.3 上测试):

[STEP 103] # cat jshell.exp
proc expect_prompt {} {
    upvar spawn_id spawn_id

    expect -ex "jshell> "

    # the CPR (cursor position report) code
    expect -ex "\x1b\[6n"

    # read the CPR result and send it the application
    expect_tty -re {\x1b\[[0-9]+;[0-9]+R}
    send $expect_out(0,string)
}

stty raw; # give tty's full control to jshell since it's crazy

spawn jshell
expect_prompt

send "3\r"
expect_prompt

send "/exit\n"
expect eof
[STEP 104] # expect jshell.exp
spawn jshell
|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

jshell> 3
$1 ==> 3

jshell> /exit
|  Goodbye
[STEP 105] #

魔术是关于CPR (cursor position report) (在页面上搜索CPR)。

1. ^[[6n (^[ == ESC == 0x1b == \u001b) 是 CPR 请求(由 jshell 发送)。
2. ^[[32;1R(第 32 行，第 1 列)之类的字符串是当前光标位置(由终端驱动程序生成并由 jshell 读回)。