1 files changed, 76 insertions, 0 deletions
diff --git a/app/TreeGrepper/FileType.hs b/app/TreeGrepper/FileType.hs
new file mode 100644
index 0000000..843eaf1
--- /dev/null
+++ b/app/TreeGrepper/FileType.hs
@@ -0,0 +1,76 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module TreeGrepper.FileType
+  ( FileType (..),
+    all,
+    Info (..),
+    BlockInfo (..),
+    info,
+  )
+where
+
+import Data.Aeson (FromJSON (parseJSON))
+import Data.Text (Text)
+import Prelude hiding (all)
+
+data FileType
+  = Elm
+  | Haskell
+  | Nix
+  | Shell
+  deriving (Show)
+
+instance FromJSON FileType where
+  parseJSON v =
+    parseJSON v >>= \case
+      "elm" -> pure Elm
+      "haskell" -> pure Haskell
+      "nix" -> pure Nix
+      "sh" -> pure Shell
+      fileType -> fail ("parsing file_type failed, got " ++ fileType)
+
+all :: [FileType]
+all =
+  [ Elm,
+    Haskell,
+    Nix,
+    Shell
+  ]
+
+data Info = Info
+  { exts :: [String],
+    lineStart :: Text,
+    block :: Maybe BlockInfo
+  }
+
+data BlockInfo = BlockInfo
+  { blockStart :: [Text],
+    blockEnd :: Text
+  }
+
+info :: FileType -> Info
+info Elm =
+  Info
+    { exts = [".elm"],
+      lineStart = "--",
+      block = Just BlockInfo {blockStart = ["{-|", "{-"], blockEnd = "-}"}
+    }
+info Haskell =
+  Info
+    { exts = [".hs"],
+      lineStart = "--",
+      block = Just BlockInfo {blockStart = ["{-"], blockEnd = "-}"}
+    }
+info Nix =
+  Info
+    { exts = [".nix"],
+      lineStart = "#",
+      block = Just BlockInfo {blockStart = ["/*"], blockEnd = "*/"}
+    }
+info Shell =
+  Info
+    { exts = [".sh"],
+      lineStart = "#",
+      block = Nothing
+    }