79 lines
1.7 KiB
AppleScript
79 lines
1.7 KiB
AppleScript
-- Using either a generic foldr(f, a, xs)
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-- reverse1 :: [a] -> [a]
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on reverse1(xs)
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script rev
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on |λ|(a, x)
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a & x
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end |λ|
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end script
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if class of xs is text then
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foldr(rev, {}, xs) as text
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else
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foldr(rev, {}, xs)
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end if
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end reverse1
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-- or the built-in reverse method for lists
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-- reverse2 :: [a] -> [a]
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on reverse2(xs)
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if class of xs is text then
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(reverse of characters of xs) as text
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else
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reverse of xs
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end if
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end reverse2
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-- TESTING reverse1 and reverse2 with same string and list ---------------------------------------------------------------------------
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on run
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script test
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on |λ|(f)
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map(f, ["Hello there !", {1, 2, 3, 4, 5}])
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end |λ|
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end script
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map(test, [reverse1, reverse2])
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end run
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-- GENERIC FUNCTIONS ---------------------------------------------------------------------------
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-- foldr :: (a -> b -> a) -> a -> [b] -> a
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on foldr(f, startValue, xs)
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tell mReturn(f)
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set v to startValue
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set lng to length of xs
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repeat with i from lng to 1 by -1
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set v to |λ|(v, item i of xs, i, xs)
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end repeat
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return v
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end tell
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end foldr
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-- map :: (a -> b) -> [a] -> [b]
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on map(f, xs)
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tell mReturn(f)
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set lng to length of xs
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set lst to {}
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repeat with i from 1 to lng
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set end of lst to |λ|(item i of xs, i, xs)
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end repeat
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return lst
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end tell
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end map
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-- Lift 2nd class handler function into 1st class script wrapper
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-- mReturn :: Handler -> Script
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on mReturn(f)
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if class of f is script then
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f
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else
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script
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property |λ| : f
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end script
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end if
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end mReturn
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