set absolutePath to "/Users/me/Documents/–Book 1「AppleScript最新リファレンス」/5000 iOSデバイスとの連携/5100 iOSデバイスからMacに画面を出力するAirServer.md"
set relativePath to "../9999_images/img-1.jpg"

set relativePath to calcAbsolutePath(absolutePath, relativePath) of me
–>　　"/Users/me/Documents/–Book 1「AppleScript最新リファレンス」/9999_images/img-1.jpg"

on calcAbsolutePath(aAbsolutePOSIXfile, bRelativePOSIXfile)
　　set aStr to current application’s NSString’s stringWithString:aAbsolutePOSIXfile
　　set bStr to current application’s NSString’s stringWithString:bRelativePOSIXfile
　　
　　set aList to aStr’s pathComponents() as list
　　set bList to bStr’s pathComponents() as list
　　
　　set aLen to length of aList
　　
　　set aCount to 1
　　repeat with i in bList
　　　　set j to contents of i
　　　　if j is not equal to ".." then
　　　　　　exit repeat
　　　　end if
　　　　set aCount to aCount + 1
　　end repeat
　　
　　set tmp1List to items 1 thru (aLen – aCount) of aList
　　set tmp2List to items aCount thru -1 of bList
　　
　　set allRes to current application’s NSString’s pathWithComponents:(tmp1List & tmp2List)
　　
　　return allRes as text
end calcAbsolutePath