Move SiteGenerator into executable only and rename library to Byg.*

byg/app/Main.hs

@@ -0,0 +1,26 @@
+module Main where
+
+import Byg.Types (Dependency)
+import qualified Byg.DependencyRunner as DR
+import qualified Byg.Types.Dependency as D
+import Byg.DependencyGenerator (evalDepGenM)
+
+import SiteGenerator (generateSite)
+
+import System.Environment (getArgs)
+import qualified Data.Text.IO as T
+
+dependencies :: [Dependency]
+dependencies = evalDepGenM generateSite
+
+main :: IO ()
+main = do
+  args <- getArgs
+  case args of
+    ["run"] -> do
+      ((), filesWritten) <- DR.runDepRunMIO $ DR.runDeps dependencies
+      putStrLn ("Files which could have been written: " ++ show filesWritten)
+    ["tree"] ->
+      T.putStr $ D.formatDependencyTrees dependencies
+    _ ->
+      error "unexpected arguments"