From 9dceeaf114b17608ff0c3f91712ea60eaaaf9d6b Mon Sep 17 00:00:00 2001
From: Stephen Chung <Stephen.Chung@intexact.com>
Date: Tue, 13 Oct 2020 15:51:59 +0800
Subject: [PATCH] Reserve ** operator.

---
 doc/src/appendix/operators.md | 1 +
 src/token.rs                  | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/doc/src/appendix/operators.md b/doc/src/appendix/operators.md
index 7f20f003..ff9b7fed 100644
--- a/doc/src/appendix/operators.md
+++ b/doc/src/appendix/operators.md
@@ -60,6 +60,7 @@ Symbols and Patterns
 | `--`                               |      decrement       | _reserved_                            |
 | `..`                               |        range         | _reserved_                            |
 | `...`                              |        range         | _reserved_                            |
+| `**`                               |    exponentiation    | _reserved_                            |
 | `#`                                |         hash         | _reserved_                            |
 | `@`                                |          at          | _reserved_                            |
 | `$`                                |        dollar        | _reserved_                            |
diff --git a/src/token.rs b/src/token.rs
index 428067ef..eb2d63f3 100644
--- a/src/token.rs
+++ b/src/token.rs
@@ -1231,6 +1231,10 @@ fn get_next_token_inner(
             ('-', _) if !state.non_unary => return Some((Token::UnaryMinus, start_pos)),
             ('-', _) => return Some((Token::Minus, start_pos)),
 
+            ('*', '*') => {
+                eat_next(stream, pos);
+                return Some((Token::Reserved("**".into()), start_pos));
+            }
             ('*', ')') => {
                 eat_next(stream, pos);
                 return Some((Token::Reserved("*)".into()), start_pos));