Modify index syntax; Clean up

src/abstract_tree/index.rs

@@ -35,8 +35,6 @@ impl AbstractTree for Index {
     fn run(&self, source: &str, context: &mut Map) -> Result<Value> {
         let value = self.collection.run(source, context)?;
 
-        println!("{self:?}");
-
         match value {
             Value::List(list) => {
                 let index = self.index.run(source, context)?.as_integer()? as usize;

tree-sitter-dust/grammar.js

@@ -114,13 +114,19 @@ module.exports = grammar({
     index: $ => prec.left(seq(
       $.expression,
       ':',
-      $.expression,
+      $._index_expression,
       optional(seq(
         '..',
-        $.expression,
+        $._index_expression,
       )),
     )),
 
+    _index_expression: $ => prec(1,choice(
+      $.integer,
+      $.identifier,
+      $.function_call,
+    )),
+
     math: $ => prec.left(seq(
       $.expression,
       $.math_operator,