Parsing

Author: ggb

day24_1.rkt

@@ -0,0 +1,39 @@
+#lang racket
+
+(struct units (count hit-points weaknesses immunities damage dtype initiative)
+  #:transparent)
+
+(define (parse-weaknesses inp)
+  (define parsed (append (string-split inp "; ") (list "" "")))
+  (define weaknesses (string-replace (if (string-contains? (first parsed) "weak") (first parsed) (second parsed)) "weak to " ""))
+  (define immunities (string-replace (if (string-contains? (first parsed) "immune") (first parsed) (second parsed)) "immune to " ""))
+  (cons (string-split weaknesses ", ") (string-split immunities ", ")))
+
+(define (parse-line l)
+  (define parsed (regexp-match #px"(\\d+) units each with (\\d+) hit points \\((.*)\\) with an attack that does (\\d+) (\\w+) damage at initiative (\\d+)" l))
+  (define weaknesses-and-immunities (parse-weaknesses (fourth parsed)))
+  (units (string->number (second parsed))
+         (string->number (third parsed))
+         (car weaknesses-and-immunities)
+         (cdr weaknesses-and-immunities)
+         (string->number (fifth parsed))
+         (sixth parsed)
+         (string->number (seventh parsed))))
+
+(define (parse-lines lines)
+  (map parse-line (rest lines)))
+
+(define (parse-input inp)
+  (define split-pos (index-of inp ""))
+  (define immune-lines (take inp split-pos))
+  (define infection-lines (drop inp (add1 split-pos)))
+  (cons (parse-lines immune-lines) (parse-lines infection-lines)))
+
+(define test-input
+  (list "Immune System:"
+        "17 units each with 5390 hit points (weak to radiation, bludgeoning) with an attack that does 4507 fire damage at initiative 2"
+        "989 units each with 1274 hit points (immune to fire; weak to bludgeoning, slashing) with an attack that does 25 slashing damage at initiative 3"
+        ""
+        "Infection:"
+        "801 units each with 4706 hit points (weak to radiation) with an attack that does 116 bludgeoning damage at initiative 1"
+        "4485 units each with 2961 hit points (immune to radiation; weak to fire, cold) with an attack that does 12 slashing damage at initiative 4"))