feat(haskell): add treesitter support

Author: horriblename

lua/aerial/backends/treesitter/extensions.lua

@@ -227,6 +227,18 @@ M.rust = {
   end,
 }
 
+M.haskell = {
+  postprocess = function(bufnr, item, match)
+    if item.kind == "Class" then
+      local class_node = node_from_match(match, "class")
+      local type = assert(node_from_match(match, "haskell_type"))
+      local name = get_node_text(type, bufnr) or "<parse error>"
+      local class = get_node_text(class_node, bufnr) or "<parse error>"
+      item.name = string.format("%s %s", class, name)
+    end
+  end,
+}
+
 M.ruby = {
   ---@note Additionally processes the following captures:
   ---      `@method`, `@receiver`, `@separator` - extends the name to "@method @reciever[@separator]@name", with @separator defaulting to "."

queries/haskell/aerial.scm

@@ -0,0 +1,36 @@
+(declarations
+  (function
+    name: (variable) @name
+    (#set! "kind" "Function")) @symbol @start)
+
+(data_type
+  name: (name) @name
+  (#set! "kind" "Struct")) @symbol @start
+
+(newtype
+  name: (name) @name
+  (#set! "kind" "Struct")) @start @symbol
+
+(declarations
+  (instance
+    name: (name) @class
+    patterns: _ @haskell_type
+    (#set! "kind" "Class")) @start @symbol)
+
+(instance
+  name: (name) @name
+
+  declarations: (instance_declarations
+    declaration: (function
+      name: (variable) @name)
+    (#set! "kind" "Method")) @start @symbol)
+
+(class
+  name: (name) @name
+  (#set! "kind" "Interface")) @start @symbol
+
+(class
+  declarations: (class_declarations
+    declaration: (signature
+      name: (variable) @name)
+    (#set! "kind" "Method")) @start @symbol)