performance - 如何在 AppleScript 的处理程序中有效地构建列表？

Question

AppleScript 文档建议使用以下代码来有效地构建列表:

set bigList to {}
set bigListRef to a reference to bigList
set numItems to 100000
set t to (time of (current date)) --Start timing operations
repeat with n from 1 to numItems
    copy n to the end of bigListRef
end
set total to (time of (current date)) - t --End timing

请注意显式引用的使用。这在脚本的顶层或显式运行处理程序中工作正常，但如果您在另一个处理程序中逐字运行相同的确切代码，如下所示:

on buildList()
    set bigList to {}
    set bigListRef to a reference to bigList
    set numItems to 100000
    set t to (time of (current date)) --Start timing operations
    repeat with n from 1 to numItems
        copy n to the end of bigListRef
    end
    set total to (time of (current date)) - t --End timing
end buildList
buildList()

它中断，产生一条错误消息，说“无法将 bigList 设为类型引用。”为什么这会中断，在 run() 之外的处理程序中有效构建列表的正确方法是什么？

Answer 1

set end of l to i好像比copy i to end of l快:

on f()
    set l to {}
    repeat with i from 1 to 100000
        set end of l to i
    end repeat
    l
end f
set t to time of (current date)
set l to f()
(time of (current date)) - t

您还可以使用脚本对象:

on f()
    script s
        property l : {}
    end script
    repeat with i from 1 to 100000
        copy i to end of l of s
    end repeat
    l of s
end f
set t to time of (current date)
set l to f()
(time of (current date)) - t

100000也超过 limit of items that can be saved in compiled scripts ，因此如果您运行该脚本并尝试将其保存为 scpt，您将收到这样的错误:

The document “Untitled” could not be saved as “Untitled.scpt”.

您可以输入 set l to f()在处理程序中，因此 l 是本地的，添加 set l to {}到最后，或将脚本另存为 .applescript。