[Nix/2023/01] Refactor

Nix/2023/01.nix

@@ -1,26 +1,29 @@
 let
-  inherit (import <nixpkgs> {}) lib;
-  input = builtins.readFile (builtins.getEnv "INPUT");
-  lines = lib.splitString "\n" (lib.removeSuffix "\n" input);
-  digits = line: map (s: builtins.fromJSON (builtins.head s)) (builtins.filter builtins.isList (builtins.split "([0-9])" line));
+  inherit (import ../lib) lib input solution;
+  inherit (builtins) fromJSON head filter isList split listToAttrs genList elemAt length stringLength substring attrNames foldl' add;
+  inherit (lib) splitString trim flatten hasPrefix last;
+
+  lines = splitString "\n" (trim input);
+  digits = line: map (s: fromJSON (head s)) (filter isList (split "([0-9])" line));
   nums = let
     words = ["one" "two" "three" "four" "five" "six" "seven" "eight" "nine"];
   in
-    builtins.listToAttrs (builtins.genList (i: {
-        name = builtins.elemAt words i;
+    listToAttrs (genList (i: {
+        name = elemAt words i;
         value = i + 1;
-      }) (builtins.length words)
-      ++ (builtins.genList (i: {
+      }) (length words)
+      ++ (genList (i: {
           name = toString i;
           value = i;
         })
         10));
-  prefixes = s: let len = builtins.stringLength s; in builtins.genList (i: builtins.substring i len s) len;
-  findWords = s: lib.flatten (map (p: builtins.filter (num: lib.hasPrefix num p) (builtins.attrNames nums)) (prefixes s));
+  prefixes = s: let len = stringLength s; in genList (i: substring i len s) len;
+  findWords = s: flatten (map (p: filter (num: hasPrefix num p) (attrNames nums)) (prefixes s));
   findNums = s: map (num: nums.${num}) (findWords s);
-  sum = builtins.foldl' builtins.add 0;
-  solve = digits: sum (map (d: builtins.head d * 10 + lib.last d) (map digits lines));
-in {
-  p1 = solve digits;
-  p2 = solve findNums;
-}
+  sum = foldl' add 0;
+  solve = digits: sum (map (d: head d * 10 + last d) (map digits lines));
+in
+  solution {
+    p1 = solve digits;
+    p2 = solve findNums;
+  }

Nix/justfile

@@ -8,7 +8,7 @@ _default:
     @just --list
 
 run year day:
-    INPUT=$(realpath ../.cache/{{year}}/{{trim_start_match(day, "0")}}) nix eval --raw -f {{year}}/{{day}}.nix --apply 's: "${toString s.p1}\n${toString s.p2}\n"'
+    INPUT=$(realpath ../.cache/{{year}}/{{trim_start_match(day, "0")}}) nix eval --raw -f {{year}}/{{day}}.nix
 
 example year day ex:
     INPUT=$(realpath ../examples/{{year}}/{{trim_start_match(day, "0")}}/{{ex}}) nix eval --raw -f {{year}}/{{day}}.nix --apply 's: "${toString s.p1}\n${toString s.p2}\n"'
@@ -20,4 +20,4 @@ test-year year:
     @set -e; for day in $(ls {{year}}); do just test {{year}} $(basename $day .nix); done
 
 test-all:
-    @set -e; for year in *; do [[ -d $year ]] || continue; just test-year $year; done
+    @set -e; for year in *; do [[ -d $year ]] && [[ "$year" != "lib" ]] || continue; just test-year $year; done

Nix/lib/default.nix

@@ -0,0 +1,11 @@
+rec {
+  inherit (import <nixpkgs> {}) lib;
+
+  input = builtins.readFile (builtins.getEnv "INPUT");
+
+  solution = {
+    p1,
+    p2 ? null,
+  }:
+    "${toString p1}\n" + (lib.optionalString (p2 != null) "${toString p2}\n");
+}