From 23db71a5f7199411ee8314d4ce2f18ec46e6fc03 Mon Sep 17 00:00:00 2001
From: Dave Halter <davidhalter88@gmail.com>
Date: Tue, 12 Jun 2018 01:50:37 +0200
Subject: [PATCH] Add a debug function for first tokens

---
 parso/pgen2/parse.py | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/parso/pgen2/parse.py b/parso/pgen2/parse.py
index aaacfce..b3673a0 100644
--- a/parso/pgen2/parse.py
+++ b/parso/pgen2/parse.py
@@ -38,6 +38,21 @@ class Stack(list):
         tos = self[-1]
         return tos[2][1]
 
+    def get_tos_first_tokens(self, grammar):
+        tos = self[-1]
+        inv_tokens = {v: k for k, v in grammar.tokens.items()}
+        inv_keywords = {v: k for k, v in grammar.keywords.items()}
+        dfa, state, nodes = tos
+
+        def check():
+            for first in dfa[1]:
+                try:
+                    yield inv_keywords[first]
+                except KeyError:
+                    yield tokenize.tok_name[inv_tokens[first]]
+
+        return list(check())
+
 
 def token_to_ilabel(grammar, type_, value):
     # Map from token to label