From 8c35a8ffabea1c989d9f449bff053081fdc987e1 Mon Sep 17 00:00:00 2001
From: Scott Wolchok <swolchok@fb.com>
Date: Thu, 7 Jan 2016 15:02:38 -0800
Subject: [PATCH] Cache scalar regexes

This improves performance on the test.yaml attached to #158 by about
35% on my machine (0.39s -> 0.25s), as measured by
`time build/util/parse < test.yaml > /dev/null`.
---
 src/exp.h         | 9 +++++++++
 src/scantoken.cpp | 4 ++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/exp.h b/src/exp.h
index f248802..ba82874 100644
--- a/src/exp.h
+++ b/src/exp.h
@@ -165,6 +165,15 @@ inline const RegEx& EndScalarInFlow() {
   return e;
 }
 
+inline const RegEx& ScanScalarEndInFlow() {
+  static const RegEx e = (EndScalarInFlow() || (BlankOrBreak() + Comment()));
+  return e;
+}
+
+inline const RegEx& ScanScalarEnd() {
+  static const RegEx e = EndScalar() || (BlankOrBreak() + Comment());
+  return e;
+}
 inline const RegEx& EscSingleQuote() {
   static const RegEx e = RegEx("\'\'");
   return e;
diff --git a/src/scantoken.cpp b/src/scantoken.cpp
index 180ad00..79e7682 100644
--- a/src/scantoken.cpp
+++ b/src/scantoken.cpp
@@ -297,8 +297,8 @@ void Scanner::ScanPlainScalar() {
 
   // set up the scanning parameters
   ScanScalarParams params;
-  params.end = (InFlowContext() ? Exp::EndScalarInFlow() : Exp::EndScalar()) ||
-               (Exp::BlankOrBreak() + Exp::Comment());
+  params.end =
+      (InFlowContext() ? Exp::ScanScalarEndInFlow() : Exp::ScanScalarEnd());
   params.eatEnd = false;
   params.indent = (InFlowContext() ? 0 : GetTopIndent() + 1);
   params.fold = FOLD_FLOW;