day 1, part 1

.gitignore

@@ -7,3 +7,5 @@
 *.scm#*
 .#*.scm
 
+easy.in
+hard.in

README.md

@@ -1,2 +1,12 @@
 # AdventOfCode-2023-functional
 
+Solutions to https://adventofcode.com/2023/
+
+This is my first experience with Lisp, so the code is probably terrible.
+
+Requirements: Guile 3 in `/usr/bin`.
+
+In a folder for a specific day,
+
+* To run (assuming NuShell): `open sample.in | ./main.scm`;
+* To run (assuming bash): `./main.scm < sample.in`.

day01-easy/main.scm

@@ -0,0 +1,61 @@
+#!/usr/bin/guile -s
+!#
+
+(use-modules (ice-9 rdelim))
+
+(define (read-lines)
+  (let loop ((line (read-line)))
+    (if
+      (eof-object? line)
+      '()
+      (cons line (loop (read-line))))))
+
+(define (map list mapper)
+  (if
+    (null? list)
+    '()
+    (cons (mapper (car list)) (map (cdr list) mapper))))
+
+(define (first-last-combine current rest)
+  (if
+    (null? current)
+    rest
+    (if
+      (null? rest)
+      current
+      (cons (car current) (cdr rest)))))
+
+(define (first-last list predicate)
+  (if
+    (null? list)
+    '()
+    (first-last-combine
+      (if
+        (predicate (car list))
+        (cons (car list) (cons (car list) '()))
+        '())
+      (first-last (cdr list) predicate))))
+
+(define (sum numbers)
+  (if
+    (null? numbers)
+      0
+      (+ (car numbers) (sum (cdr numbers)))
+      ))
+
+(define (solve-line line)
+  (
+    #!(lambda (first-last-result) (sum (map first-last-result (lambda (char) (string->number (string char))))))!#
+    (lambda (first-last-result) (string->number (list->string first-last-result)))
+    (first-last
+      (string->list line)
+      (lambda (char) (if (char-numeric? char) #t #f)))))
+
+(define (solve-all lines)
+  (if
+    (null? lines)
+    0
+    (+ (solve-line (car lines)) (solve-all (cdr lines)))
+    ))
+
+(display (solve-all (read-lines)))

day01-easy/sample.in

@@ -0,0 +1,4 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet