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(define-module (aoc-utils)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (ice-9 regex)
#:use-module (ice-9 rdelim)
#:export (file->list
file->str
file->matrix
lines->number-list
<matrix>
matrix
make-matrix
matrix-inner
matrix-width
matrix-height
matrix-ref
matrix-valid-x?
matrix-valid-y?
matrix-valid-point?
list-flatten))
(define (file->list filename)
(let ((lines (string-split (call-with-input-file filename read-string) #\Newline)))
; Remove EOF token
(take lines (1- (length lines)))))
(define (file->str filename)
(call-with-input-file filename read-string))
(define (file->matrix filename)
(map string->list (file->list filename)))
(define (lines->number-list lines)
(map (lambda (line)
(map string->number (string-split line #\Space)))
lines))
(define (remove-nth l n)
"Remove the `N' element from `L', returning a new list."
(append (list-head l n) (list-tail l (1+ n))))
(define (indexes lst)
"Get the indexes for `lst'."
(let ((retval '()))
(do ((i (1- (length lst)) (1- i)))
((< i 0))
(set! retval (cons i retval)))
retval))
;; Matrix utilities
(define-record-type <matrix>
(matrix inner width height)
matrix?
(inner matrix-inner)
(width matrix-width)
(height matrix-height))
(define (make-matrix lst)
(let ((height (length lst))
(width (length (car lst))))
(matrix (list-flatten lst) width height)))
(define (list-flatten lst)
(apply append lst))
(define (matrix-ref matrix x y)
(if (matrix-valid-point? matrix x y)
(list-ref (matrix-inner matrix)
(+ x (* y (matrix-height matrix))))
#f))
(define (matrix-valid-x? matrix x)
(and (>= x 0) (< x (matrix-width matrix))))
(define (matrix-valid-y? matrix y)
(and (>= y 0) (< y (matrix-height matrix))))
(define (matrix-valid-point? matrix x y)
(and (matrix-valid-x? matrix x)
(matrix-valid-y? matrix y)))
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