First commit

LICENSE

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+Copyright Author name here (c) 2021
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+# Langton Ant in Haskell

Setup.hs

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+import Distribution.Simple
+main = defaultMain

hie.yaml

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+cradle:
+  stack:
+    - path: "./src/Main.hs"
+      component: "langtonant:exe:langtonant"

langtonant.cabal

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+name:                langtonant
+version:             0.1.0.0
+-- synopsis:
+-- description:
+homepage:            https://github.com/dhilst/langtonant#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Daniel Hilst Selli
+maintainer:          Daniel Hilst Selli
+copyright:           2021 Author name here
+category:            Web
+build-type:          Simple
+cabal-version:       >=1.10
+extra-source-files:  README.md
+
+executable langtonant
+  ghc-options: -threaded
+  hs-source-dirs:      src
+  main-is:             Main.hs
+  default-language:    Haskell2010
+  build-depends:       base >= 4.7 && < 5
+                     , vty
+                     , array
+                     , process
+                     , ansi-terminal

src/Main.hs

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+module Main where
+
+import Control.Concurrent
+import Control.Monad
+import Data.Array
+import Data.Char
+import Data.Function
+import Debug.Trace
+import System.Console.ANSI (clearScreen)
+import qualified System.Process as SP
+
+data Direction
+  = DUp
+  | DDown
+  | DLeft
+  | DRight
+  deriving (Show)
+
+data Color
+  = Black
+  | White
+  deriving (Show)
+
+type Pos = (Int, Int)
+
+type Universe = Array Pos Color
+
+data Ant =
+  Ant
+    { pos :: Pos
+    , dir :: Direction
+    }
+  deriving (Show)
+
+h = 50
+
+w = 100
+
+start = (h `div` 2, w `div` 2)
+
+mkArray :: (Int, Int) -> Array (Int, Int) Color
+mkArray (maxx, maxy) =
+  array
+    ((0, 0), (maxy - 1, maxx - 1))
+    [((y, x), Black) | y <- [0 .. maxy - 1], x <- [0 .. maxx - 1]]
+
+mkUniverse :: Universe
+mkUniverse = mkArray (w, h)
+
+mkAnt :: Ant
+mkAnt =
+  let (y, x) = start
+   in Ant {pos = (y, x), dir = DUp}
+
+-- sleep seconds
+delay :: IO ()
+delay =
+  let n = 3
+   in threadDelay (10000 * n)
+
+-- clear terminal
+clear :: IO ()
+clear = do
+  _ <- SP.system "reset"
+  return ()
+
+colorToChar :: Color -> Char
+colorToChar Black = '.'
+colorToChar White = '@'
+
+printUniverse :: Universe -> IO ()
+printUniverse m = do
+  forM_ (assocs m) $ \((y, x), cell) -> do
+    putChar . colorToChar $ cell
+    putChar '\n' & when (x == w - 1)
+
+turnLeft :: Direction -> Direction
+turnLeft DUp = DLeft
+turnLeft DDown = DRight
+turnLeft DLeft = DDown
+turnLeft DRight = DUp
+
+turnRight :: Direction -> Direction
+turnRight DUp = DRight
+turnRight DDown = DLeft
+turnRight DLeft = DUp
+turnRight DRight = DDown
+
+turnAnt :: Color -> Direction -> Direction
+turnAnt White dir = turnRight dir
+turnAnt Black dir = turnLeft dir
+
+flipColor :: Color -> Color
+flipColor Black = White
+flipColor White = Black
+
+updateCell :: Pos -> Color -> Universe -> Universe
+updateCell (y, x) color universe = universe // [((y, x), color)]
+
+flipCell :: Pos -> Universe -> Universe
+flipCell (y, x) universe =
+  let c = universe ! (y, x)
+   in updateCell (y, x) (flipColor c) universe
+
+moveForward :: Direction -> (Int, Int) -> (Int, Int)
+moveForward DLeft (y, x) = (y, (x - 1) `mod` w)
+moveForward DRight (y, x) = (y, (x + 1) `mod` w)
+moveForward DUp (y, x) = ((y - 1) `mod` h, x)
+moveForward DDown (y, x) = ((y + 1) `mod` h, x)
+
+moveAnt :: Color -> Ant -> Ant
+moveAnt currentColor Ant {pos = (y, x), dir = dir} =
+  let newDir = turnAnt currentColor dir
+      (x', y') = moveForward newDir (y, x)
+   in Ant {pos = (x', y'), dir = newDir}
+
+getCurrentCellColor :: Ant -> Universe -> Color
+getCurrentCellColor Ant {pos = (y, x)} universe = universe ! (y, x)
+
+stepSystem :: (Ant, Universe) -> (Ant, Universe)
+stepSystem (ant@Ant {pos = pos}, universe) =
+  let currentCellColor = getCurrentCellColor ant universe
+      newAnt = moveAnt currentCellColor ant
+   in (newAnt, flipCell pos universe)
+
+runSystem :: (Ant, Universe) -> Int -> IO ()
+runSystem system@(ant, universe) step = do
+  clearScreen
+  printUniverse universe
+  print $ "Step: " ++ show step
+  delay
+  runSystem (stepSystem system) (step + 1)
+
+main :: IO ()
+main = runSystem (mkAnt, mkUniverse) 0

stack.yaml

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+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-18.6
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+extra-deps:
+  - vty-5.33
+  - array-0.5.4.0
+  - process-1.6.9.0
+  - ansi-terminal-0.11
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.7"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor

stack.yaml.lock

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+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages:
+- completed:
+    hackage: vty-5.33@sha256:8da1652d64e24c9e011384628de340b2877f0148de7ef57baf66cd2e9a35c6c6,22294
+    pantry-tree:
+      size: 5393
+      sha256: f83f9245266d28f8521227cf551d6498a4ad7b22f1ac98c5992c287e6fc06d08
+  original:
+    hackage: vty-5.33
+- completed:
+    hackage: array-0.5.4.0@sha256:2b2425e01d592c0e66594c008405ea4c6f6e4d929daeddabbd81be9bb49ebffa,1588
+    pantry-tree:
+      size: 1135
+      sha256: e17dfafde2f226674cffd56b1f445c332b6e5855860f79dedd9de0b6916e7ff0
+  original:
+    hackage: array-0.5.4.0
+- completed:
+    hackage: process-1.6.9.0@sha256:372de796fea9d40e6d02269d5df466c9b8d641f145fad3c1add59db7baeea19e,2576
+    pantry-tree:
+      size: 1211
+      sha256: 9d21df864535dcc65e11fd108c4678fdadf2d53bb9ffd1fda142369c797f31c1
+  original:
+    hackage: process-1.6.9.0
+- completed:
+    hackage: ansi-terminal-0.11@sha256:97470250c92aae14c4c810d7f664c532995ba8910e2ad797b29f22ad0d2d0194,3307
+    pantry-tree:
+      size: 1461
+      sha256: 4098c4b8bb503fcf0730aedc8247a479d3e22fd1fe4c6b4b2b2b5da30bdfb713
+  original:
+    hackage: ansi-terminal-0.11
+snapshots:
+- completed:
+    size: 587113
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/18/6.yaml
+    sha256: f74c482d7c93739ecf3abfbc0f2dea1c20a2dfb2462c689846ed55a9653b66f7
+  original: lts-18.6