AppleScript: separating items into categories

After at least a week, I have finally made enough progress on a script I am working on that categorizes items. It's not finished, and the code thus far is clunky and could maybe use some cleaning up, but here's my progress thus far:

Code:

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on indexesOf(theSubstring, theString)
        set oldDelims to AppleScript's text item delimiters
        set AppleScript's text item delimiters to theSubstring
        set stringList to every text item of theString
        set AppleScript's text item delimiters to oldDelims
        set theIndex to 1
        set theIndexes to {}
        repeat with X from 2 to count of stringList
                set theIndex to theIndex + (length of item (X - 1) of stringList)
                if (X > 2) then
                        set theIndex to theIndex + (length of theSubstring)
                end if
                copy theIndex to end of theIndexes
        end repeat
        return theIndexes
end indexesOf

on separateItemsIntoCategories(theContent, theCategories, categoryID, contentOrganized, splitStringDelimiter)
        try
                set oldDelims to AppleScript's text item delimiters
                -- Separate the items
                set theDelims to {}
                repeat with X from 1 to count of theCategories
                        set delim to ""
                        set delim to (item X of theCategories) & categoryID
                        copy delim to end of theDelims
                end repeat
                set AppleScript's text item delimiters to theDelims
                set splitContent to every text item of theContent
                set currentIndex to 1
                set categorizedContent to {}
                set categoryNames to {}
                set categoryContent to {}
                if (contentOrganized is false) then
                        -- Content is not organized.
                        set theString to ""
                        set categoryNameBeforeContent to true
                        try
                                repeat with X from 1 to length of splitContent
                                        get item X of theDelims
                                end repeat
                        on error errMsg
                                set categoryNameBeforeContent to false
                        end try
                        set categoryIndexes to {}
                        repeat with X from 1 to length of theCategories
                                set theIndexes to indexesOf(item X of theCategories, theContent)
                                copy theIndexes to end of categoryIndexes
                                copy item X of theCategories to end of categoryNames
                        end repeat
                        set expandedIndexes to {}
                        set expandedCategories to {}
                        repeat with X from 1 to count of categoryIndexes
                                set theIndexes to item X of categoryIndexes
                                repeat with I from 1 to count of theIndexes
                                        copy item I of theIndexes to end of expandedIndexes
                                        copy item X of theCategories & categoryID to end of expandedCategories
                                end repeat
                        end repeat
                        repeat with X from 1 to ((count of splitContent) - 1)
                                set delim to ""
                                if (categoryNameBeforeContent is false) then
                                        set theString to theString & item X of splitContent
                                end if
                                repeat with I from 1 to count of expandedIndexes
                                        log "expandedIndexes item I: " & item I of expandedIndexes
                                        if (item I of expandedIndexes is ((length of theString) + 1)) then
                                                set delim to item I of expandedCategories
                                        end if
                                end repeat
                                if (categoryNameBeforeContent is true) then
                                        log item X of splitContent
                                        set theString to theString & delim & item X of splitContent
                                else
                                        set theString to theString & delim
                                end if
                                set comparisonString to ""
                                repeat with Y from 1 to count of theCategories
                                        set comparisonString to item Y of theCategories & categoryID
                                        log "comparison string: " & comparisonString
                                        if (comparisonString is delim) then
                                                exit repeat
                                        end if
                                end repeat
                                log "category is " & item Y of theCategories
                                log "length of theString: " & length of theString
                                log theString
                        end repeat
                        log X
                end if
                set AppleScript's text item delimiters to oldDelims
                return categorizedContent
        on error errMsg
                log ("Error in separateItemsIntoCategories: " & errMsg)
        end try
end separateItemsIntoCategories

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So the script now knows which parts of the string belong under which categories. You pass along a string to be categorized for "theString," and a list of the categories for "theCategories." Now I just need it to apply that knowledge to the task at hand.