AppleScript如何让嵌套操作不受外层tell语句作用域影响

问题根因 #

你遇到的报错和ignoring application responses无关：这个语句的作用仅为忽略目标应用的响应超时、不等待命令返回结果，完全不会改变命令的发送目标。外层嵌套的tell application "System Events"、tell application process myApp会给块内所有未显式指定执行目标的命令，自动加上当前tell对象的隐含前缀，导致POSIX file、current date这类标准AppleScript原生命令，被错误发送给目标应用进程执行，最终触发寻址错误。 #

解决方案 #

方案1：用tell current application块强制指定执行目标 #

将不需要外层tell作用域的代码包裹在tell current application块内，强制块内所有命令由AppleScript运行时本身执行，不受外层tell作用域影响：

set myApp to "someApp"
set pPath to POSIX file "/Volumes/myDisk/outputPath"

tell application myApp to activate

tell application "System Events"
    tell application process myApp
        tell window myApp

            --some code here

            repeat while progress indicator 1 of sheet 1 exists
                -- 强制块内命令由脚本本身执行
                tell current application
                    -- 如果确实需要忽略响应可以保留ignoring块，不需要可以直接删除
                    ignoring application responses
                        set newPath to POSIX file pPath as alias
                        set currentDate to current date
                    end ignoring
                end tell
            end repeat

            --some code here

        end tell
    end tell
end tell

方案2：提前定义不需要动态计算的变量到外层tell块外 #

如果部分变量不需要在循环内动态计算，可以提前在外层非tell作用域完成定义，避免进入tell块后寻址错误：

set myApp to "someApp"
set pPath to POSIX file "/Volumes/myDisk/outputPath"
-- 提前定义不需要动态计算的变量
set newPath to pPath as alias

tell application myApp to activate

tell application "System Events"
    tell application process myApp
        tell window myApp

            --some code here

            repeat while progress indicator 1 of sheet 1 exists
                tell current application
                    set currentDate to current date
                end tell
            end repeat

            --some code here

        end tell
    end tell
end tell

补充优化技巧 #

如果仅单个变量/命令需要脱离外层tell作用域，不需要写完整块，给变量添加my前缀即可强制指定为脚本本身的属性/命令：

set currentDate to my (current date)
set newPath to my (POSIX file pPath as alias)

内容的提问来源于stack exchange，提问作者userX