script spd
　　property aList : {}
　　property bList : {}
end script

set (aList of spd) to {}
set (bList of spd) to {}

tell application "CotEditor"
　　set dCount to count every document
　　if dCount is not equal to 2 then
　　　　display notification "Error: This script needs only 2 documents"
　　　　return –Document number Error
　　end if
　　
　　tell window 1
　　　　set w1Bounds to bounds
　　　　copy w1Bounds to {w1X1, w1Y1, w1X2, w1Y2}
　　　　set w1Doc to document of it
　　end tell
　　
　　tell window 2
　　　　set w2Bounds to bounds
　　　　copy w2Bounds to {w2X1, w2Y1, w2X2, w2Y2}
　　　　set w2Doc to document of it
　　end tell
　　
　　if w1X1 > w2X1 then
　　　　set {w1, w2} to {2, 1}
　　else
　　　　set {w1, w2} to {1, 2}
　　end if
　　
　　tell document w1 –左ウィンドウ
　　　　set (aList of spd) to paragraphs of contents
　　end tell
　　
　　tell document w2 –右ウィンドウ
　　　　set (bList of spd) to paragraphs of contents
　　end tell
　　
end tell

–ゴミ掃除
set (aList of spd) to cleanUp1DList((aList of spd), {"
"}) of me

set (bList of spd) to cleanUp1DList((bList of spd), {"
"}) of me

–差分計算
set (cList of spd) to getDiffBetweenLists((aList of spd), (bList of spd)) of me

–結果出力テキスト組み立て
set aRes to listToTextUsingDelim(addItems of (cList of spd), "")
set bRes to listToTextUsingDelim(minusItems of (cList of spd), "")

–結果の新規書類への出力
set d3 to makeNewCotEditorDoc("左→右で追加された項目" & return & return & aRes) of me
set d4 to makeNewCotEditorDoc("左→右で削除された項目" & return & return & bRes) of me

on getDiffBetweenLists(aArray as list, bArray as list)
　　set allSet to current application’s NSMutableSet’s setWithArray:aArray
　　allSet’s addObjectsFromArray:bArray
　　
　　–重複する要素のみ抜き出す
　　set duplicateSet to current application’s NSMutableSet’s setWithArray:aArray
　　duplicateSet’s intersectSet:(current application’s NSSet’s setWithArray:bArray)
　　
　　–重複部分を削除する
　　allSet’s minusSet:duplicateSet
　　set resArray to (allSet’s allObjects()) as list
　　
　　set aSet to current application’s NSMutableSet’s setWithArray:aArray
　　set bSet to current application’s NSMutableSet’s setWithArray:resArray
　　aSet’s intersectSet:bSet –積集合
　　set addRes to aSet’s allObjects() as list
　　
　　set cSet to current application’s NSMutableSet’s setWithArray:bArray
　　cSet’s intersectSet:bSet –積集合
　　set minusRes to cSet’s allObjects() as list
　　
　　return {addItems:minusRes, minusItems:addRes}
end getDiffBetweenLists

on cleanUp1DList(aList as list, cleanUpItems as list)
　　set bList to {}
　　repeat with i in aList
　　　　set j to contents of i
　　　　if j is not in cleanUpItems then
　　　　　　set the end of bList to j
　　　　end if
　　end repeat
　　return bList
end cleanUp1DList

–デリミタ文字を指定してリストを文字列化
on listToTextUsingDelim(aList, aDelim)
　　set curDelim to AppleScript’s text item delimiters
　　set AppleScript’s text item delimiters to aDelim
　　set outText to every text item of aList
　　set outText to outText as string
　　set AppleScript’s text item delimiters to curDelim
　　return outText
end listToTextUsingDelim

–指定テキストでCotEditorの新規書類を作成
on makeNewCotEditorDoc(aCon)
　　tell application "CotEditor"
　　　　activate
　　　　set newDoc to make new document
　　　　tell newDoc
　　　　　　set contents to aCon
　　　　end tell
　　end tell
end makeNewCotEditorDoc