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#!/usr/bin/guile -s
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!#
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(use-modules (ice-9 rdelim))
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(define (read-lines)
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(let loop ((line (read-line)))
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(if
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(eof-object? line)
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'()
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(cons line (loop (read-line))))))
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(define (id value) value)
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(define (compose result-transformer f argument-transformer)
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(lambda (value)
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(result-transformer (f (argument-transformer value)))))
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(define Y (lambda (f) (f (lambda (x) ((Y f) x)))))
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(define (reduce-right reducer initial) (Y
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(lambda (f) (lambda (list)
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(if (null? list) initial (reducer (car list) (f (cdr list))))))))
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(define (map mapper)
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(reduce-right
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(lambda (current accumulator) (cons (mapper current) accumulator))
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'()))
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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 (repeat value) (Y
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(lambda (f) (lambda (n)
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(if (= n 0) '() (cons value (f (- n 1))))))))
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(define (is-numeric-char char) (if (char-numeric? char) #t #f))
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(define (first-last predicate) (compose
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id
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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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(map (lambda (entry) (if (predicate entry) ((repeat entry) 2) '())))))
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(define solve-line (compose
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(lambda (first-last-result) (string->number (list->string first-last-result)))
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(first-last is-numeric-char)
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string->list))
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(define (solve-all lines) (sum ((map solve-line) lines)))
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(display (solve-all (read-lines)))
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