Day 1

lib/common.ex

@@ -1,2 +1,4 @@
 defmodule Aoc2023.Common do
+  def stringify(s) when is_binary(s) do s end
+  def stringify(n) when is_integer(n) do inspect(n) end
 end

lib/day1.ex

@@ -2,14 +2,48 @@ defmodule Aoc2023.Day1 do
   use Aoc2023
 
   def parse(input) do
+    fn (replacement) ->
       input
+      |> String.split("\n")
+      |> Enum.map(replacement)
+      |> Enum.map(fn (line) -> 
+        line
+        |> String.to_charlist()
+        |> Enum.filter(&(?0 <= &1 && &1 <= ?9))
+        |> Enum.map(&(&1 - ?0))
+      end)
+      |> Enum.map(&[List.first(&1), List.last(&1)])
+      |> Enum.filter(fn (l) -> Enum.all?(l, &(&1 != nil)) end)
+      |> Enum.map(&Integer.undigits/1)
+      |> Enum.sum
+    end
   end
 
   def part1(input) do
-    nil
+    input.(fn line -> line end)
   end
 
+  @numbers [
+    "one",
+    "two",
+    "three",
+    "four",
+    "five",
+    "six",
+    "seven",
+    "eight",
+    "nine",
+  ]
+
+  defp replacements(line) do
+    line
+    |> String.replace(@numbers, fn (n) -> Integer.to_string(Enum.find_index(@numbers, &(&1 == n)) + 1) <> String.slice(n, 1..String.length(n)) end)
+  end
+
+  defp replacements_rec(line) do
+    if replacements(line) == line, do: line, else: replacements_rec(replacements(line))
+  end
   def part2(input) do
-    nil
+    input.(&replacements_rec/1)
  end
 end

lib/mix_tasks.ex

@@ -1,5 +1,6 @@
 defmodule Mix.Tasks.Aoc do
   use Mix.Task
+  import Aoc2023.Common
 
   defp module(1), do: Aoc2023.Day1
   # [MODULE INSERTION POINT]  
@@ -7,14 +8,18 @@ defmodule Mix.Tasks.Aoc do
   defp base_dir(), do: System.get_env("AOC_BASE")
 
   defp tests(day) do
-    File.ls!(tests_dir(day)) |> Enum.filter(&(not String.contains?(&1, ".")))
+    case File.ls(tests_dir(day)) do
+      {:ok, paths} -> paths |> Enum.filter(&(not String.contains?(&1, ".")))
+      {:error, e} -> dbg(e)
+        []
+    end
   end
 
   defp read(path) do
     f = File.open!(path, [:utf8])
     contents = IO.read(f, :eof)
     :ok = File.close(f)
-    contents
+    String.trim(contents)
   end
 
   defp test(day, test) do
@@ -55,14 +60,15 @@ defmodule Mix.Tasks.Aoc do
     create_file("#{base_dir()}/lib/day#{day}.ex", """
     defmodule Aoc2023.Day#{day} do
     	use Aoc2023
+
     	def parse(input) do
     		input
     	end
+
     	def part1(input) do
-    		input
     	end
+
     	def part2(input) do
-    		input
     	end
     end
     """)
@@ -82,7 +88,7 @@ defmodule Mix.Tasks.Aoc do
   end
 
   defp run(day, ["test", "new"]) do
-    last = tests(day) |> Enum.map(&String.to_integer(&1)) |> Enum.max(empty_fallback: fn -> 1 end)
+    last = tests(day) |> Enum.map(&String.to_integer(&1)) |> Enum.max(&>=/2, fn -> 0 end)
     create_file("#{tests_dir(day)}#{last + 1}", IO.read(:stdio, :eof))
   end
 
@@ -101,7 +107,7 @@ defmodule Mix.Tasks.Aoc do
       p1 = mod.part1(parsed)
 
       if p1e do
-        if to_string(p1) != p1e do
+        if stringify(p1) != p1e do
           IO.puts("Failed at #{test}.1: expected #{p1e}, got:")
           dbg(p1)
         end
@@ -113,7 +119,7 @@ defmodule Mix.Tasks.Aoc do
       p2 = mod.part2(parsed)
 
       if p2e do
-        if to_string(p2) != p2e do
+        if stringify(p2) != p2e do
           IO.puts("Failed at #{test}.2: expected #{p2e}, got:")
           dbg(p2)
         end

tests/day1/1

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

tests/day1/1.1

@@ -0,0 +1 @@
+142

tests/day1/1.2

@@ -0,0 +1 @@
+142

tests/day1/2

@@ -0,0 +1,7 @@
+two1nine
+eightwothree
+abcone2threexyz
+xtwone3four
+4nineeightseven2
+zoneight234
+7pqrstsixteen

tests/day1/2.1

@@ -0,0 +1 @@
+209

tests/day1/2.2

@@ -0,0 +1 @@
+281