From bbddd62c7071b8cb2f4abcc47c613c61f3bf7801 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20P=C3=A4tzel?= <david.paetzel@posteo.de>
Date: Tue, 7 Jan 2020 08:45:50 +0100
Subject: [PATCH] Add applicative CLI option parsing

---
 default.nix | 20 ++++++++++++--------
 haga.cabal  |  3 +++
 src/Main.hs | 42 +++++++++++++++++++++++++++++++++++-------
 3 files changed, 50 insertions(+), 15 deletions(-)

diff --git a/default.nix b/default.nix
index b02396b..a849063 100644
--- a/default.nix
+++ b/default.nix
@@ -1,20 +1,24 @@
-{ mkDerivation, base, Cabal, extra, monad-loops, MonadRandom, pipes
-, protolude, QuickCheck, quickcheck-instances, random, random-fu
-, random-shuffle, stdenv, text
+{ mkDerivation, base, Cabal, extra, monad-loops, MonadRandom
+, optparse-applicative, pipes, protolude, QuickCheck
+, quickcheck-instances, random, random-fu, random-shuffle, stdenv
+, text
 }:
 mkDerivation {
-  pname = "ga";
+  pname = "haga";
   version = "0.1.0.0";
   src = ./.;
   isLibrary = true;
   isExecutable = true;
   libraryHaskellDepends = [
-    base extra monad-loops MonadRandom pipes protolude QuickCheck
-    quickcheck-instances random random-fu random-shuffle text
+    base extra monad-loops MonadRandom optparse-applicative pipes
+    protolude QuickCheck quickcheck-instances random random-fu
+    random-shuffle text
   ];
   executableHaskellDepends = [
-    base Cabal extra monad-loops MonadRandom pipes protolude QuickCheck
-    quickcheck-instances random random-fu random-shuffle text
+    base Cabal extra monad-loops MonadRandom optparse-applicative pipes
+    protolude QuickCheck quickcheck-instances random random-fu
+    random-shuffle text
   ];
+  description = "Simplistic genetic algorithms library";
   license = stdenv.lib.licenses.gpl3;
 }
diff --git a/haga.cabal b/haga.cabal
index 8ab8596..9d2a470 100644
--- a/haga.cabal
+++ b/haga.cabal
@@ -24,6 +24,7 @@ library
                      , extra
                      , MonadRandom
                      , monad-loops
+                     , optparse-applicative
                      , pipes
                      , protolude
                      , QuickCheck
@@ -44,6 +45,7 @@ executable haga
                      , extra
                      , MonadRandom
                      , monad-loops
+                     , optparse-applicative
                      , pipes
                      , protolude
                      , QuickCheck
@@ -66,6 +68,7 @@ executable haga-tests
                      , extra
                      , MonadRandom
                      , monad-loops
+                     , optparse-applicative
                      , pipes
                      , protolude
                      , QuickCheck
diff --git a/src/Main.hs b/src/Main.hs
index dd13cf1..b15b70d 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -2,21 +2,49 @@
 {-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE OverloadedStrings #-}
 
+import Options.Applicative
 import Pipes
 import Pretty
-import Protolude hiding (for)
+import Protolude hiding (for, option)
 import System.IO
 import Szenario191
 
-mkPop = population 100 (I prios [])
+data Options
+  = Options
+      { iterations :: N,
+        populationSize :: N
+      }
+
+options :: Parser Options
+options =
+  Options
+    <$> option auto
+          ( long "iterations"
+              <> short 'i'
+              <> metavar "N"
+              <> value 1000
+              <> help "Number of iterations"
+          )
+    <*> option auto
+          ( long "population-size"
+              <> short 'p'
+              <> metavar "N"
+              <> value 100
+              <> help "Population size"
+          )
+
+optionsWithHelp =
+  info (helper <*> options)
+    ( fullDesc
+        <> progDesc "Run a GA"
+        <> header "haga - Haskell implementations of EAs"
+    )
 
 main :: IO ()
-main = do
-  args <- getArgs
-  let t = fromMaybe 100 $ headMay args >>= readMaybe
+main = execParser optionsWithHelp >>= \opts -> do
   hSetBuffering stdout NoBuffering
-  pop <- mkPop
-  pop' <- runEffect $ for (run 2 1 (5 / 100) pop (steps t)) log
+  pop <- population (populationSize opts) (I prios [])
+  pop' <- runEffect $ for (run 2 1 (5 / 100) pop (steps $ iterations opts)) log
   (res, _) <- bests 5 pop'
   sequence_ $ format <$> res
   where