如何仅替换Applescript中匹配搜索字符串的第一个匹配项？

我有此脚本，但我想更改，使其仅替换匹配搜索字符串的第一个匹配项：

查找和替换文本时的

（文本、搜索字符串、替换字符串）
将AppleScript的文本项分隔符设置为搜索字符串
将文本项设置为文本的每个文本项
将AppleScript的文本项分隔符设置为替换字符串
将文本设置为字符串形式的文本项
将AppleScript的文本项分隔符设置为“”
返回文本
end FindReplaceIntext
findAndReplaceInText（“susan”、“s”、“t”）--返回“tutan”，但我希望“tusan”

更新Vadian代码以修复替换最后一个字符时的错误。但我仍然希望有一个更简单/更短的解决方案：

on findAndReplaceFirstOccurrenceInText(theText, theSearchString, theReplacementString)
set theOffset to offset of theSearchString in theText
if theOffset is 0 then
    return theText
else if theOffset is 1 then
    tell theText to return theReplacementString & text (theOffset + (length of theSearchString)) thru -1
else if theOffset is length of theText then
    tell theText to return text 1 thru (theOffset - 1) & theReplacementString
else
    tell theText to return text 1 thru (theOffset - 1) & theReplacementString & text (theOffset + (length of theSearchString)) thru -1
end if

---

end FindReplaceFirstOccurrenceIntext

我将更新vadians代码以修复替换最后一个字符时的错误。但我仍然希望有一个更简单/更短的解决方案：

on findAndReplaceFirstOccurrenceInText(theText, theSearchString, theReplacementString)
set theOffset to offset of theSearchString in theText
if theOffset is 0 then
    return theText
else if theOffset is 1 then
    tell theText to return theReplacementString & text (theOffset + (length of theSearchString)) thru -1
else if theOffset is length of theText then
    tell theText to return text 1 thru (theOffset - 1) & theReplacementString
else
    tell theText to return text 1 thru (theOffset - 1) & theReplacementString & text (theOffset + (length of theSearchString)) thru -1
end if

---

end FindReplaceFirstOccurrenceIntext

无任何错误处理：

to findAndReplaceFirstOccurrenceInText(theText, theSearchString, theReplacementString)
    set AppleScript's text item delimiters to theSearchString
    return text item 1 of theText & theReplacementString & text (text item 2) thru (text item -1) of theText
end findAndReplaceFirstOccurrenceInText

---

无任何错误处理：

to findAndReplaceFirstOccurrenceInText(theText, theSearchString, theReplacementString)
    set AppleScript's text item delimiters to theSearchString
    return text item 1 of theText & theReplacementString & text (text item 2) thru (text item -1) of theText
end findAndReplaceFirstOccurrenceInText

---

这个有效，而且更短。但是，当我想替换字符串的最后几个字符时，仍然存在一个问题：findAndReplaceFirstOccurrenceInText（“susan”、“an”、“1”）--返回“sus1n”我的疏忽，现在已修复。这有效，而且更短。但是，当我想替换字符串的最后几个字符时，仍然存在一个问题：findAndReplaceFirstOccurrenceInText（“susan”、“an”、“1”）——返回“sus1n”我的疏忽，现已修复。