diff --git a/corpus/test.langexp b/corpus/test.langexp
index b9e7510..c076d9b 100644
--- a/corpus/test.langexp
+++ b/corpus/test.langexp
@@ -220,7 +220,7 @@ parse_number : Unit! = {
 }
 
 : example of or_in and or_out usage for template operators (tuple input and tuple output)
-( & ) |-> 'a |-> 'b <-| 'x <-| 'y = ('a := 'x) && ('b := 'y);
+( & ) --|-> 'a --|-> 'b <-|-- 'x <-|-- 'y = ('a := 'x) && ('b := 'y);
 
 : function, that return result ('!' not used on calls)
 : useful when tuples returned
diff --git a/grammar.js b/grammar.js
index e736950..c92a60c 100644
--- a/grammar.js
+++ b/grammar.js
@@ -18,8 +18,8 @@ module.exports = grammar({
 
     _statement: $ => choice(
       $.import,
-      $.type_definition,
       $.function_definition,
+      $.type_definition,
       $.typeclass_definition,
       $.empty_lines,
     ),
@@ -41,15 +41,6 @@ module.exports = grammar({
 
     // --- definitions
 
-    type_definition: $ => seq(
-      optional($.definition_info),
-      repeat($.annotation_info),
-      optional('^'),
-      field('name', $.simple_type_identifier),
-      optional(seq(repeat($.argument_type_identifier), '=', $.variant_type)),
-      choice(seq('{', repeat($.function_definition), '}'), ';')
-    ),
-
     function_definition: $ => seq(
       optional($.definition_info),
       repeat($.annotation_info),
@@ -71,6 +62,15 @@ module.exports = grammar({
       choice(seq('=', choice(prec(2, choice($.block, $.array)), seq($._super_expression, ';'))), ';'),
     ),
 
+    type_definition: $ => seq(
+      optional($.definition_info),
+      repeat($.annotation_info),
+      optional('^'),
+      field('name', $.simple_type_identifier),
+      optional(seq(repeat($.argument_type_identifier), '=', $.variant_type)),
+      choice(seq('{', repeat($.function_definition), '}'), ';')
+    ),
+
     typeclass_definition: $ => seq(
       optional($.definition_info),
       // no argumenmts => no annotation info
@@ -256,7 +256,18 @@ module.exports = grammar({
     _do: $ => choice('=>', 'do'),
     _var_let: $ => choice(choice('%', 'let'), choice('$', 'var')),
     _optional_result: $ => choice('?', '!'),
-    _reference: $ => choice(choice('->', 'out'), choice('<-', 'in'), choice('<>', 'ref'), choice('|->', 'or_out'), choice('<-|', 'or_in')),
+    //_reference: $ => choice(choice('->', 'out'), choice('<-', 'in'), choice('<>', 'ref'), choice('|->', 'or_out'), choice('<-|', 'or_in')),
+
+    // _reference: $ => seq(optional(choice('->', 'out')), optional(choice('<>', 'ref')), optional(choice('--', 'const')), optional(choice('<-', 'in'))),
+
+    _reference: $ => choice(choice('<-', '<>', '--', '->',
+                                   '<-|<>', '<-|--', '<>|->', '--|->', '<>|--', '<-|->',
+                                   '<-|<>|->', '<-|--|->', '<-|<>|--', '<>|--|->',
+                                   '<-|<>|--|->'),
+                            choice('in', 'ref', 'const', 'out',
+                                   'in|ref', 'in|const', 'ref|out', 'const|out', 'ref|const', 'in|out',
+                                   'in|ref|out', 'in|const|out', 'in|ref|const', 'ref|const|out',
+                                   'in|ref|const|out')),
 
     _name_identifier: $ => choice($.argument_name_identifier, $.simple_name_identifier),
     _type_identifier: $ => choice($.argument_type_identifier, $.simple_type_identifier),