go

go/.exercism/config.json

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+{
+  "authors": [
+    "lpil"
+  ],
+  "files": {
+    "solution": [
+      "src/go.gleam"
+    ],
+    "test": [
+      "test/go_test.gleam"
+    ],
+    "exemplar": [
+      ".meta/example.gleam"
+    ],
+    "invalidator": [
+      "gleam.toml",
+      "manifest.toml"
+    ]
+  },
+  "forked_from": [
+    "elm/go"
+  ],
+  "blurb": "Learn usage of Result by applying the rules of the game of Go"
+}

go/.exercism/metadata.json

@@ -0,0 +1 @@
+{"track":"gleam","exercise":"go","id":"5f92ded7f0d94054b5eb825d783c3245","url":"https://exercism.org/tracks/gleam/exercises/go","handle":"fw353qwgs","is_requester":true,"auto_approve":false}

go/.gitignore

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+*.beam
+*.ez
+build
+erl_crash.dump

go/HELP.md

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+# Help
+
+## Running the tests
+
+To run the tests, run the command `gleam test` from within the exercise directory.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit src/go.gleam` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Gleam track's documentation](https://exercism.org/docs/tracks/gleam)
+- The [Gleam track's programming category on the forum](https://forum.exercism.org/c/programming/gleam)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+To get help if you're having trouble, you can use one of the following resources:
+
+- [gleam.run](https://gleam.run/documentation/) is the gleam official documentation.
+- [Discord](https://discord.gg/Fm8Pwmy) is the discord channel.
+- [StackOverflow](https://stackoverflow.com/questions/tagged/gleam) can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.

go/HINTS.md

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+# Hints
+
+- The [Result module][result-module] has some useful functions for working with the Result type, such as `result.map` and `result.try`.
+
+[result-module]: https://hexdocs.pm/gleam_stdlib/gleam/result.html

go/README.md

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+# Go
+
+Welcome to Go on Exercism's Gleam Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
+
+## Introduction
+
+## Results
+
+Gleam doesn't use exceptions for error handling, instead the generic `Result` type is returned by functions that can either succeed or fail.
+
+The `Result` type is built into the language so you don't need to define or import it, but if you were to define it yourself it would look like this:
+
+```gleam
+pub type Result(value, error) {
+  Ok(value)
+  Error(error)
+}
+```
+
+The `Ok` variant is returned when a function succeeds, and the `Error` variant is returned when a function fails.
+
+Results are very common in Gleam, and Gleam programmers will commonly use the [`gleam/result` module](https://hexdocs.pm/gleam_stdlib/gleam/result.html) to make working with them easier.
+
+The `result.map` function can be used to call a function on the value inside a result if it is an `Ok`, or to pass through an `Error` unchanged.
+
+```gleam
+Ok(1)
+|> result.map(fn(x) { x + 1 })
+// -> Ok(2)
+
+Error("Oh no!")
+|> result.map(fn(x) { x + 1 })
+// -> Error("Oh no!")
+```
+
+The `result.try` function is similar, but the callback function is expected to return a result. This is useful for chaining together multiple functions that return results.
+
+```gleam
+Ok(1)
+|> result.try(fn(x) { Ok(x + 1) })
+// -> Ok(2)
+
+Ok(1)
+|> result.try(fn(x) { Error("Nope!") })
+// -> Error("Nope!")
+```
+
+## Instructions
+
+In this exercise, you'll be applying the [rules of the game of Go](https://matmoore.github.io/learngo/). The rules themselves are already written, you just need to apply them in order to update the Game and to handle any errors / violations of the rules.
+
+The game is represented as follows:
+
+```gleam
+pub type Player {
+  Black
+  White
+}
+
+
+pub type Game {
+  Game(
+    white_captured_stones: Int,
+    black_captured_stones: Int,
+    player: Player,
+    error: String,
+  )
+}
+```
+
+There are 4 rules in the game:
+
+- Each point can only have one stone.
+- Opposition stones can be captured.
+- You can not place a stone where it would capture itself.
+- You can not use the same point twice.
+
+## 1. Apply the rules
+
+Write the content of the `apply_rules` function, which takes an initial `Game` and a set of rules, and returns the new `Game` after the rules have been applied.
+
+Three of the rules all check for violations of the rules and may return an error, and so have the return type of `Result(Game, String)`. If any of these rules fail, the original game should be returned, but with the `error` field updated with the relevant error.
+
+The other rule does not check for violations and so cannot fail (although it can return a changed `Game`), and so has the return type of `Game`.
+
+If all the rules pass, then any changes to `Game` from the rules should be kept, and the player should be changed.
+
+```gleam
+pub fn apply_rules(
+  game: Game,
+  rule1: fn(Game) -> Result(Game, String),
+  rule2: fn(Game) -> Game,
+  rule3: fn(Game) -> Result(Game, String),
+  rule4: fn(Game) -> Result(Game, String),
+) -> Game {
+  // -> If all rules pass, return a `Game` with all changes from the rules applied, and change player
+  // -> If any rule fails, return the original Game, but with the error field set
+}
+```
+
+## Source
+
+### Created by
+
+- @lpil

go/gleam.toml

@@ -0,0 +1,14 @@
+name = "go"
+version = "0.1.0"
+
+[dependencies]
+gleam_otp = "~> 0.7 or ~> 1.0"
+gleam_stdlib = ">= 0.54.0 or ~> 1.0"
+simplifile = "~> 1.0"
+gleam_erlang = ">= 0.25.0 and < 1.0.0"
+gleam_yielder = ">= 1.1.0 and < 2.0.0"
+gleam_regexp = ">= 1.1.0 and < 2.0.0"
+gleam_deque = ">= 1.0.0 and < 2.0.0"
+
+[dev-dependencies]
+exercism_test_runner = "~> 1.9"

go/manifest.toml

@@ -0,0 +1,31 @@
+# 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 = "exercism_test_runner", version = "1.9.0", build_tools = ["gleam"], requirements = ["argv", "gap", "glance", "gleam_community_ansi", "gleam_erlang", "gleam_json", "gleam_stdlib", "simplifile"], otp_app = "exercism_test_runner", source = "hex", outer_checksum = "0B17BB25F2FF1E60266467C24FE0CA04005410306AA05E9A4B41B1852D72865C" },
+  { name = "filepath", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "filepath", source = "hex", outer_checksum = "67A6D15FB39EEB69DD31F8C145BB5A421790581BD6AA14B33D64D5A55DBD6587" },
+  { name = "gap", version = "1.1.3", build_tools = ["gleam"], requirements = ["gleam_community_ansi", "gleam_stdlib"], otp_app = "gap", source = "hex", outer_checksum = "6EF5E3B523FDFBC317E9EA28D5163EE04744A97C007106F90207569789612291" },
+  { name = "glance", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib", "glexer"], otp_app = "glance", source = "hex", outer_checksum = "E155BA1A787FD11827048355021C0390D2FE9A518485526F631A9D472858CC6D" },
+  { 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 = "2.0.0", build_tools = ["gleam"], requirements = ["gleam_json", "gleam_stdlib"], otp_app = "gleam_community_colour", source = "hex", outer_checksum = "FDD6AC62C6EC8506C005949A4FCEF032038191D5EAAEC3C9A203CD53AE956ACA" },
+  { name = "gleam_deque", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_deque", source = "hex", outer_checksum = "64D77068931338CF0D0CB5D37522C3E3CCA7CB7D6C5BACB41648B519CC0133C7" },
+  { name = "gleam_erlang", version = "0.34.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "0C38F2A128BAA0CEF17C3000BD2097EB80634E239CE31A86400C4416A5D0FDCC" },
+  { name = "gleam_json", version = "2.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_json", source = "hex", outer_checksum = "C55C5C2B318533A8072D221C5E06E5A75711C129E420DD1CE463342106012E5D" },
+  { name = "gleam_otp", version = "0.16.1", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "50DA1539FC8E8FA09924EB36A67A2BBB0AD6B27BCDED5A7EF627057CF69D035E" },
+  { name = "gleam_regexp", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_regexp", source = "hex", outer_checksum = "7F5E0C0BBEB3C58E57C9CB05FA9002F970C85AD4A63BA1E55CBCB35C15809179" },
+  { name = "gleam_stdlib", version = "0.55.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "32D8F4AE03771516950047813A9E359249BD9FBA5C33463FDB7B953D6F8E896B" },
+  { name = "gleam_yielder", version = "1.1.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_yielder", source = "hex", outer_checksum = "8E4E4ECFA7982859F430C57F549200C7749823C106759F4A19A78AEA6687717A" },
+  { name = "glexer", version = "2.2.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "glexer", source = "hex", outer_checksum = "5C235CBDF4DA5203AD5EAB1D6D8B456ED8162C5424FE2309CFFB7EF438B7C269" },
+  { name = "simplifile", version = "1.7.0", build_tools = ["gleam"], requirements = ["filepath", "gleam_stdlib"], otp_app = "simplifile", source = "hex", outer_checksum = "1D5DFA3A2F9319EC85825F6ED88B8E449F381B0D55A62F5E61424E748E7DDEB0" },
+]
+
+[requirements]
+exercism_test_runner = { version = "~> 1.9" }
+gleam_deque = { version = ">= 1.0.0 and < 2.0.0" }
+gleam_erlang = { version = ">= 0.25.0 and < 1.0.0" }
+gleam_otp = { version = "~> 0.7 or ~> 1.0" }
+gleam_regexp = { version = ">= 1.1.0 and < 2.0.0" }
+gleam_stdlib = { version = ">= 0.54.0 or ~> 1.0" }
+gleam_yielder = { version = ">= 1.1.0 and < 2.0.0" }
+simplifile = { version = "~> 1.0" }

go/src/go.gleam

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+import gleam/result
+
+pub type Player {
+  Black
+  White
+}
+
+pub type Game {
+  Game(
+    white_captured_stones: Int,
+    black_captured_stones: Int,
+    player: Player,
+    error: String,
+  )
+}
+
+pub fn apply_rules(
+  game: Game,
+  rule1: fn(Game) -> Result(Game, String),
+  rule2: fn(Game) -> Game,
+  rule3: fn(Game) -> Result(Game, String),
+  rule4: fn(Game) -> Result(Game, String),
+) -> Game {
+  case rule2(game) |> rule1 |> result.try(rule3) |> result.try(rule4) {
+    Error(err) -> Game(..game, error: err)
+    Ok(g) ->
+      case g.player {
+        Black -> Game(..g, player: White)
+        White -> Game(..g, player: Black)
+      }
+  }
+}

go/test/go_test.gleam

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+import exercism/should
+import exercism/test_runner
+import go.{type Game, Black, Game, White}
+
+pub fn main() {
+  test_runner.main()
+}
+
+fn identity(x: Game) -> Game {
+  x
+}
+
+fn identity_rule(game: Game) -> Result(Game, String) {
+  Ok(game)
+}
+
+fn error_rule(_game: Game, message: String) -> Result(Game, String) {
+  Error(message)
+}
+
+fn new_game() -> Game {
+  Game(0, 0, White, "")
+}
+
+fn ko_rule() -> String {
+  "Cannot repeat a previously played board position"
+}
+
+fn liberty_rule() -> String {
+  "Cannot place a stone with no liberties"
+}
+
+fn one_stone_per_point_rule() -> String {
+  "You can't put a stone on top of another stone"
+}
+
+fn add_white_captured_stone(game: Game) -> Game {
+  Game(..game, white_captured_stones: 1)
+}
+
+pub fn change_player_if_all_rules_pass_test() {
+  new_game()
+  |> go.apply_rules(identity_rule, identity, identity_rule, identity_rule)
+  |> should.equal(change_player(new_game()))
+}
+
+pub fn retain_error_and_player_if_ko_rule_fails_test() {
+  new_game()
+  |> go.apply_rules(identity_rule, identity, identity_rule, error_rule(
+    _,
+    ko_rule(),
+  ))
+  |> should.equal(Game(..new_game(), error: ko_rule()))
+}
+
+pub fn retain_error_and_player_if_liberty_rule_fails_test() {
+  new_game()
+  |> go.apply_rules(
+    identity_rule,
+    identity,
+    error_rule(_, liberty_rule()),
+    identity_rule,
+  )
+  |> should.equal(Game(..new_game(), error: liberty_rule()))
+}
+
+pub fn retain_error_and_player_if_one_stone_per_point_rule_fails_test() {
+  new_game()
+  |> go.apply_rules(
+    error_rule(_, one_stone_per_point_rule()),
+    identity,
+    identity_rule,
+    identity_rule,
+  )
+  |> should.equal(Game(..new_game(), error: one_stone_per_point_rule()))
+}
+
+pub fn retain_changes_from_capture_rule_and_change_player_test() {
+  new_game()
+  |> go.apply_rules(
+    identity_rule,
+    add_white_captured_stone,
+    identity_rule,
+    identity_rule,
+  )
+  |> should.equal(
+    new_game()
+    |> add_white_captured_stone
+    |> change_player,
+  )
+}
+
+pub fn discard_changes_from_capture_rule_if_subsequent_rule_fails_test() {
+  new_game()
+  |> go.apply_rules(
+    identity_rule,
+    add_white_captured_stone,
+    identity_rule,
+    error_rule(_, ko_rule()),
+  )
+  |> should.equal(Game(..new_game(), error: ko_rule()))
+}
+
+fn change_player(game: Game) -> Game {
+  let new_player = case game.player {
+    White -> Black
+    Black -> White
+  }
+  Game(..game, player: new_player)
+}