set up stuff; do day 1 of year 2025

.gitignore

···
+*.beam
+*.ez
+/build
+erl_crash.dump
+.envrc
+/input/

README.md

···
+# advent_of_code
+My aoc code  
+Using gladvent
+
+
+
+## General Workflow
+
+1. run `gleam run -- new <target-day> --fetch=true --year=<target-year>`
+2. add example data to `inputs/<target-year>/<target-day>.example.txt`
+3. work on solution
+4. test solution using `gleam run -- run <target-day> --example=true`
+5. once it works run `gleam run -- run X`

gleam.toml

···
+name = "advent_of_code"
+version = "1.0.0"
+
+# Fill out these fields if you intend to generate HTML documentation or publish
+# your project to the Hex package manager.
+#
+# description = ""
+# licences = ["Apache-2.0"]
+# repository = { type = "github", user = "", repo = "" }
+# links = [{ title = "Website", href = "" }]
+#
+# For a full reference of all the available options, you can have a look at
+# https://gleam.run/writing-gleam/gleam-toml/.
+
+[dependencies]
+gleam_stdlib = ">= 0.44.0 and < 2.0.0"
+gladvent = ">= 2.2.1 and < 3.0.0"
+
+[dev-dependencies]
+gleeunit = ">= 1.0.0 and < 2.0.0"

manifest.toml

···
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "argv", version = "1.0.2", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "BA1FF0929525DEBA1CE67256E5ADF77A7CDDFE729E3E3F57A5BDCAA031DED09D" },
+  { name = "envoy", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "envoy", source = "hex", outer_checksum = "850DA9D29D2E5987735872A2B5C81035146D7FE19EFC486129E44440D03FD832" },
+  { name = "filepath", version = "1.1.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "B06A9AF0BF10E51401D64B98E4B627F1D2E48C154967DA7AF4D0914780A6D40A" },
+  { name = "gladvent", version = "2.2.1", build_tools = ["gleam"], requirements = ["argv", "envoy", "filepath", "gleam_erlang", "gleam_http", "gleam_httpc", "gleam_json", "gleam_otp", "gleam_package_interface", "gleam_stdlib", "glint", "parallel_map", "shellout", "simplifile", "snag", "spinner", "tom"], otp_app = "gladvent", source = "hex", outer_checksum = "82DCA16931B5950EEAEFB192524E52BC16D9BDDFCEB501ADAC5094430684440F" },
+  { name = "gleam_community_ansi", version = "1.4.3", build_tools = ["gleam"], requirements = ["gleam_community_colour", "gleam_regexp", "gleam_stdlib"], otp_app = "gleam_community_ansi", source = "hex", outer_checksum = "8A62AE9CC6EA65BEA630D95016D6C07E4F9973565FA3D0DE68DC4200D8E0DD27" },
+  { name = "gleam_community_colour", version = "2.0.2", build_tools = ["gleam"], requirements = ["gleam_json", "gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "E34DD2C896AC3792151EDA939DA435FF3B69922F33415ED3C4406C932FBE9634" },
+  { name = "gleam_erlang", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "1124AD3AA21143E5AF0FC5CF3D9529F6DB8CA03E43A55711B60B6B7B3874375C" },
+  { name = "gleam_http", version = "4.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_http", source = "hex", outer_checksum = "82EA6A717C842456188C190AFB372665EA56CE13D8559BF3B1DD9E40F619EE0C" },
+  { name = "gleam_httpc", version = "4.1.1", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_http", "gleam_stdlib"], otp_app = "gleam_httpc", source = "hex", outer_checksum = "C670EBD46FC1472AD5F1F74F1D3938D1D0AC1C7531895ED1D4DDCB6F07279F43" },
+  { name = "gleam_json", version = "3.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "44FDAA8847BE8FC48CA7A1C089706BD54BADCC4C45B237A992EDDF9F2CDB2836" },
+  { name = "gleam_otp", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "BA6A294E295E428EC1562DC1C11EA7530DCB981E8359134BEABC8493B7B2258E" },
+  { name = "gleam_package_interface", version = "3.0.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_package_interface", source = "hex", outer_checksum = "8F2D19DE9876D9401BB0626260958A6B1580BB233489C32831FE74CE0ACAE8B4" },
+  { name = "gleam_regexp", version = "1.1.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_regexp", source = "hex", outer_checksum = "9C215C6CA84A5B35BB934A9B61A9A306EC743153BE2B0425A0D032E477B062A9" },
+  { name = "gleam_stdlib", version = "0.67.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "6368313DB35963DC02F677A513BB0D95D58A34ED0A9436C8116820BF94BE3511" },
+  { name = "gleam_yielder", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_yielder", source = "hex", outer_checksum = "8E4E4ECFA7982859F430C57F549200C7749823C106759F4A19A78AEA6687717A" },
+  { name = "glearray", version = "2.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "glearray", source = "hex", outer_checksum = "5E272F7CB278CC05A929C58DEB58F5D5AC6DB5B879A681E71138658D0061C38A" },
+  { name = "gleeunit", version = "1.9.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "DA9553CE58B67924B3C631F96FE3370C49EB6D6DC6B384EC4862CC4AAA718F3C" },
+  { name = "glint", version = "1.2.1", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_community_colour", "gleam_stdlib", "snag"], otp_app = "glint", source = "hex", outer_checksum = "2214C7CEFDE457CEE62140C3D4899B964E05236DA74E4243DFADF4AF29C382BB" },
+  { name = "parallel_map", version = "3.0.2", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib", "gleam_yielder"], otp_app = "parallel_map", source = "hex", outer_checksum = "20E8EFFECA25D6061EE81A6E7C96C05783994D9E4191482B86DB13AA5618EEFA" },
+  { name = "repeatedly", version = "2.1.2", build_tools = ["gleam"], requirements = [], otp_app = "repeatedly", source = "hex", outer_checksum = "93AE1938DDE0DC0F7034F32C1BF0D4E89ACEBA82198A1FE21F604E849DA5F589" },
+  { name = "shellout", version = "1.7.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "shellout", source = "hex", outer_checksum = "1BDC03438FEB97A6AF3E396F4ABEB32BECF20DF2452EC9A8C0ACEB7BDDF70B14" },
+  { name = "simplifile", version = "2.3.1", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "957E0E5B75927659F1D2A1B7B75D7B9BA96FAA8D0C53EA71C4AD9CD0C6B848F6" },
+  { name = "snag", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "snag", source = "hex", outer_checksum = "274F41D6C3ECF99F7686FDCE54183333E41D2C1CA5A3A673F9A8B2C7A4401077" },
+  { name = "spinner", version = "1.3.1", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_stdlib", "glearray", "repeatedly"], otp_app = "spinner", source = "hex", outer_checksum = "21BDE7FF9D7D9ACBB4086C0D5C86F0A90CE6B0F3CB593B41D03384AE7724B5B4" },
+  { name = "tom", version = "1.1.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "tom", source = "hex", outer_checksum = "0910EE688A713994515ACAF1F486A4F05752E585B9E3209D8F35A85B234C2719" },
+]
+
+[requirements]
+gladvent = { version = ">= 2.2.1 and < 3.0.0" }
+gleam_stdlib = { version = ">= 0.44.0 and < 2.0.0" }
+gleeunit = { version = ">= 1.0.0 and < 2.0.0" }

src/advent_of_code.gleam

···
+import gladvent
+
+pub fn main() -> Nil {
+  gladvent.run()
+}

src/aoc_2025/day_1.gleam

···
+import gleam/int
+import gleam/list
+import gleam/string
+
+pub fn parse(input: String) -> List(Rotation) {
+  let lines = string.split(input, "\n")
+  list.map(lines, fn(line) {
+    case line {
+      "L" <> amount -> {
+        let assert Ok(amount) = int.parse(amount)
+        Left(amount)
+      }
+      "R" <> amount -> {
+        let assert Ok(amount) = int.parse(amount)
+        Right(amount)
+      }
+      _ -> {
+        echo line
+        panic as "Invalid input o.o"
+      }
+    }
+  })
+}
+
+pub type Rotation {
+  Left(amount: Int)
+  Right(amount: Int)
+}
+
+pub fn pt_1(input: List(Rotation)) {
+  pt_1_loop(input, 50, 0)
+}
+
+fn pt_1_loop(input: List(Rotation), position: Int, zero_count: Int) -> Int {
+  case input {
+    [] -> zero_count
+    [rotation, ..rest] ->
+      case do_rotation_pt_1(position, rotation) {
+        0 -> pt_1_loop(rest, 0, zero_count + 1)
+        otherwise -> pt_1_loop(rest, otherwise, zero_count)
+      }
+  }
+}
+
+fn do_rotation_pt_1(position: Int, rotation: Rotation) {
+  case rotation {
+    Left(amount:) -> position - amount
+    Right(amount:) -> position + amount
+  }
+  |> handle_overflow_pt_1
+}
+
+fn handle_overflow_pt_1(position) {
+  case position {
+    _ if position > 99 -> handle_overflow_pt_1(position - 100)
+    _ if position < 0 -> handle_overflow_pt_1(position + 100)
+    _ -> position
+  }
+}
+
+pub fn pt_2(input: List(Rotation)) {
+  list.fold(input, #(50, 0), fn(acc, rotation) {
+    let #(position, zeros) = acc
+    rotate(position, rotation, zeros)
+  }).1
+}
+
+fn pt_2_loop(input: List(Rotation), position: Int, zero_count: Int) -> Int {
+  case input {
+    [] -> zero_count
+    [rotation, ..rest] -> {
+      let #(position, zeros) = do_rotation_pt_2(position, rotation)
+      pt_2_loop(rest, position, zero_count + zeros)
+    }
+  }
+}
+
+fn rotate(from position: Int, by rotation: Rotation, zeros zeros: Int) {
+  case rotation {
+    Left(0) -> #(position, zeros)
+    // we're at 0; roll over to 99
+    Left(amount:) if position == 0 -> rotate(99, Left(amount - 1), zeros)
+    // we're at 1; next one is 0
+    Left(amount:) if position == 1 -> rotate(0, Left(amount - 1), zeros + 1)
+    Left(amount:) -> rotate(position - 1, Left(amount - 1), zeros)
+
+    Right(0) -> #(position, zeros)
+    // we're at 99; roll over to 0
+    Right(amount:) if position == 99 -> rotate(0, Right(amount - 1), zeros + 1)
+    Right(amount:) -> rotate(position + 1, Right(amount - 1), zeros)
+  }
+}
+
+fn do_rotation_pt_2(position: Int, rotation: Rotation) {
+  case rotation {
+    Left(amount:) -> position - amount
+    Right(amount:) -> position + amount
+  }
+  |> handle_overflow_pt_2(0)
+}
+
+fn handle_overflow_pt_2(position, zero_count) {
+  case position {
+    _ if position > 99 -> handle_overflow_pt_2(position - 100, zero_count + 1)
+    _ if position < 0 -> handle_overflow_pt_2(position + 100, zero_count + 1)
+    _ -> #(position, zero_count)
+  }
+}

test/advent_of_code_test.gleam

···
+import gleeunit
+
+pub fn main() -> Nil {
+  gleeunit.main()
+}
+
+// gleeunit test functions end in `_test`
+pub fn hello_world_test() {
+  let name = "Joe"
+  let greeting = "Hello, " <> name <> "!"
+
+  assert greeting == "Hello, Joe!"
+}