33 lines
960 B
Clojure
33 lines
960 B
Clojure
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(meditations
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"Sequence comprehensions can bind each element in turn to a symbol"
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(= __
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(for [index (range 6)]
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index))
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"They can easily emulate mapping"
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(= '(0 1 4 9 16 25)
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(map (fn [index] (* index index))
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(range 6))
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(for [index (range 6)]
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__))
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"And also filtering"
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(= '(1 3 5 7 9)
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(filter odd? (range 10))
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(for [index __ :when (odd? index)]
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index))
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"And they trivially allow combinations of the two transformations"
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(= '(1 9 25 49 81)
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(map (fn [index] (* index index))
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(filter odd? (range 10)))
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(for [index (range 10) :when __]
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__))
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"More complex transformations can be formed with multiple binding forms"
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(= [[:top :left] [:top :middle] [:top :right]
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[:middle :left] [:middle :middle] [:middle :right]
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[:bottom :left] [:bottom :middle] [:bottom :right]]
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(for [row [:top :middle :bottom] column [:left :middle :right]]
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__)))
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