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@ -28,37 +28,32 @@ |
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(define (Y f) (f (lambda (x) ((Y f) x)))) |
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(define (Y2 f) (f (lambda (x y) ((Y2 f) x y)))) |
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(define (reduce-right reducer initial) (Y |
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(define (reduce-right initial reducer) (Y |
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(lambda (f) (lambda (values) |
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(if (null? values) initial (reducer (car values) (f (cdr values)))))))) |
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(define (map mapper) (reduce-right |
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(lambda (current accumulator) (cons (mapper current) accumulator)) |
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'())) |
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(define (map mapper) (reduce-right '() |
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(lambda (current accumulator) (cons (mapper current) accumulator)))) |
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(define (concat left right) |
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((reduce-right |
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(lambda (current accumulator) (cons current accumulator)) |
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right) |
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left)) |
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((reduce-right right (lambda (current accumulator) (cons current accumulator))) |
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left)) |
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;=============== flat ====================== |
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(define flat (reduce-right concat '())) |
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(define flat (reduce-right '() concat)) |
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(assert-eq "flat test 1 failed" |
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'(1 2 3 4 5 (6 7) 8) |
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(flat '((1 2) (3 4) (5 (6 7) 8)))) |
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(define (filter predicate) (reduce-right |
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(define (filter predicate) (reduce-right '() |
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(lambda (current accumulator) |
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(if (predicate current) (cons current accumulator) accumulator)) |
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'())) |
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(if (predicate current) (cons current accumulator) accumulator)))) |
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;=============== first ====================== |
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(define (first predicate) (reduce-right |
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(define (first predicate) (reduce-right '() |
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(lambda (current accumulator) |
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(if (predicate current) current accumulator)) |
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'())) |
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(if (predicate current) current accumulator)))) |
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(assert-eq "first with is-not-empty test 1 failed" |
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'(1 2 3) |
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@ -70,12 +65,12 @@ |
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(define (compose-two f g) (lambda (x) (f (g x)))) |
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(define compose (reduce-right compose-two id)) |
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(define compose (reduce-right id compose-two)) |
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(define (combine combiner) |
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(lambda (a b) (if (null? a) b (if (null? b) a (combiner a b))))) |
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(define sum (reduce-right + 0)) |
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(define sum (reduce-right 0 +)) |
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(define (repeat value) (Y |
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(lambda (f) (lambda (n) |
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@ -214,9 +209,8 @@ |
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(define solve-line (compose (list |
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string->number |
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list->string |
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(reduce-right |
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(combine (lambda (left right) (cons (car left) (cdr right)))) |
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'()) |
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(reduce-right '() |
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(combine (lambda (left right) (cons (car left) (cdr right))))) |
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(map (lambda (char) ((repeat char) 2))) |
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car |
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(tokenize-aoc solution-tokens) |
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