add variadic_parameter; closes #68

grammar.js

@@ -836,12 +836,19 @@ module.exports = grammar({
         ),
       ),
 
+    variadic_parameter: ($) =>
+      seq(
+        "...",
+        $._parameters,
+      ),
+
     _parameters: ($) =>
       choice(
         $.identifier,
         $.typed_parameter,
         $.default_parameter,
         $.typed_default_parameter,
+        $.variadic_parameter,
       ),
 
     parameters: ($) => seq("(", optional(trailCommaSep1($._parameters)), ")"),

test/corpus/functions.txt

@@ -1,3 +1,31 @@
+============================================
+Functions: Variadic parameters
+============================================
+
+func sum(first_number: float, ...numbers: Array) -> float:
+	return 0.0
+
+---
+
+(source
+  (function_definition
+    (name)
+    (parameters
+      (typed_parameter
+        (identifier)
+        (type
+          (identifier)))
+      (variadic_parameter
+        (typed_parameter
+          (identifier)
+          (type
+            (identifier)))))
+    (type
+      (identifier))
+    (body
+      (return_statement
+        (float)))))
+
 ============================================
 Functions: Generic types in parameters and return types
 ============================================