feat: drop haskell-tree-sitter

Drop haskell-tree-sitter in favor of custom bindings to tree-sitter.
haskell-tree-sitter is outdated and seems unmaintained.

The implementation add low-level bindings to tree-sitter and traverses
the AST in Haskell.

We suspect that many FFI calls are more expensive than performing just a
single API call to a C function that does the traversal.

This will be addressed in upcoming commits.

@prerequisite-for add-languages-elm-shell-nix

1 files changed, 65 insertions, 0 deletions

diff --git a/app/TreeSitter.hs b/app/TreeSitter.hs
new file mode 100644
index 0000000..e911d1b
--- /dev/null
+++ b/app/TreeSitter.hs
@@ -0,0 +1,65 @@
+module TreeSitter where
+
+-- | References: [tree-sitter/api.h](https://github.com/tree-sitter/tree-sitter/blob/master/lib/include/tree_sitter/api.h)
+
+import Foreign.C.String (CString)
+import Foreign.C.Types (CInt (..))
+import Foreign.Ptr (Ptr)
+import Foreign.Storable (Storable (..), peek)
+
+data Parser
+
+data Language
+
+data Tree = Tree
+
+data Node = Node
+
+instance Storable Node where
+  sizeOf _ = 32
+
+data Point = Point
+  { row :: CInt,
+    column :: CInt
+  } deriving (Show)
+
+instance Storable Point where
+  sizeOf _ = 8
+  alignment _ = 8
+  peek p = Point <$> peekByteOff p 0 <*> peekByteOff p 4
+
+withParser :: Ptr Language -> (Ptr Parser -> IO a) -> IO a
+withParser l f = do
+  p <- ts_parser_new
+  ts_parser_set_language p l
+  x <- f p
+  ts_parser_delete p
+  pure x
+
+foreign import ccall unsafe "ts_node_start_point_p" ts_node_start_point :: Ptr Node -> Ptr Point -> IO ()
+
+foreign import ccall unsafe "ts_node_end_point_p" ts_node_end_point :: Ptr Node -> Ptr Point -> IO ()
+
+foreign import ccall unsafe "ts_node_start_byte_p" ts_node_start_byte :: Ptr Node -> IO CInt
+
+foreign import ccall unsafe "ts_node_end_byte_p" ts_node_end_byte :: Ptr Node -> IO CInt
+
+foreign import ccall unsafe "ts_node_type_p" ts_node_type :: Ptr Node -> IO CString
+
+foreign import ccall unsafe "ts_node_named_child_p" ts_node_named_child :: Ptr Node -> CInt -> Ptr Node -> IO ()
+
+foreign import ccall unsafe "ts_node_named_child_count_p" ts_node_named_child_count :: Ptr Node -> IO CInt
+
+foreign import ccall unsafe "ts_tree_root_node_p" ts_tree_root_node :: Ptr Tree -> Ptr Node -> IO ()
+
+foreign import ccall unsafe "ts_tree_delete" ts_tree_delete :: Ptr Tree -> IO ()
+
+foreign import ccall unsafe "ts_parser_parse_string" ts_parser_parse_string :: Ptr Parser -> Ptr Tree -> CString -> CInt -> IO (Ptr Tree)
+
+foreign import ccall unsafe "ts_parser_new" ts_parser_new :: IO (Ptr Parser)
+
+foreign import ccall unsafe "ts_parser_delete" ts_parser_delete :: Ptr Parser -> IO ()
+
+foreign import ccall unsafe "ts_parser_set_language" ts_parser_set_language :: Ptr Parser -> Ptr Language -> IO ()
+
+foreign import ccall unsafe "tree_sitter_haskell" tree_sitter_haskell :: Ptr Language