From 5fdeefdfc4273a8e57e760aae234b1411da8788c Mon Sep 17 00:00:00 2001
From: Tommy Yu <tommy.yu@auckland.ac.nz>
Date: Sat, 5 May 2018 17:39:38 +1200
Subject: [PATCH] Add the LET keyword to lexer.

---
 src/calmjs/parse/lexers/es2015.py | 10 +++++++++-
 src/calmjs/parse/tests/lexer.py   |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/calmjs/parse/lexers/es2015.py b/src/calmjs/parse/lexers/es2015.py
index 1d4182f..9debce4 100644
--- a/src/calmjs/parse/lexers/es2015.py
+++ b/src/calmjs/parse/lexers/es2015.py
@@ -20,6 +20,11 @@
 )
 
 
+es2015_keywords = (
+    'LET',
+)
+
+
 class Lexer(ES5Lexer):
     """
     ES2015 lexer.
@@ -32,7 +37,10 @@ class Lexer(ES5Lexer):
     t_ARROW          = r'=>'
     t_SPREAD         = r'\.\.\.'
 
-    tokens = ES5Lexer.tokens + (
+    keywords = ES5Lexer.keywords + es2015_keywords
+    keywords_dict = dict((key.lower(), key) for key in keywords)
+
+    tokens = ES5Lexer.tokens + es2015_keywords + (
         # ES2015 punctuators
         'ARROW', 'SPREAD',    # => ...
 
diff --git a/src/calmjs/parse/tests/lexer.py b/src/calmjs/parse/tests/lexer.py
index 79efe8b..e7c52ae 100644
--- a/src/calmjs/parse/tests/lexer.py
+++ b/src/calmjs/parse/tests/lexer.py
@@ -463,6 +463,10 @@
         'const_keyword',
         ('const c',
          ['CONST const', 'ID c']),
+    ), (
+        'let_keyword',
+        ('let c',
+         ['LET let', 'ID c']),
     ), (
         'punctuators',
         ('=> ...',