RFC: Porting map() and grep() to AppleScript

[mjg]

No real Perl code here, but I thought it would be neat to try to port the map() and grep() functions to AppleScript and see if that much-maligned language could use a little higher-order programming love.

I've also posted a thread on MacScripter, but here's the code in question. Thoughts?

on map over theList given script:theScript
    set resultList to {}
    repeat with theItem in theList
        set resultList to resultList & theScript's lambda(theItem)
    end repeat
    return resultList
end map

on grep over theList given script:theScript
    set resultList to {}
    repeat with theItem in theList
        tell theScript
            if lambda(theItem) is true then
                set resultList to resultList & theItem
            end if
        end tell
    end repeat
    return resultList
end grep

-- end library

script mapScript
    property HowMany : 0
    
    on lambda(someone)
        set HowMany to HowMany + 1
        return someone & " Gardner " & HowMany
    end lambda
end script
map over {"Mark", "Erin", "David"} given script:mapScript

script grepScript
    on lambda(someone)
        considering case
            if contents of someone is equal to "David" then
                return true
            end if
            return false
        end considering
    end lambda
end script
grep over {"Mark", "Erin", "David"} given script:grepScript