From 1df482d51fff5c91888d4c8e86831a6c605db34f Mon Sep 17 00:00:00 2001
From: get <45425365+Minty-Meeo@users.noreply.github.com>
Date: Wed, 7 Jun 2023 20:07:54 -0500
Subject: Prefer static const std::regex

std::regex has a relatively expensive constructor, and these are unchanging regexes.
---
 Source/Core/InputCommon/ControlReference/ExpressionParser.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

(limited to 'Source/Core/InputCommon/ControlReference/ExpressionParser.cpp')

diff --git a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
index 65f9ceba4f..c93dcc5c3d 100644
--- a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
+++ b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
@@ -102,10 +102,10 @@ std::string Lexer::FetchDelimString(char delim)
 
 std::string Lexer::FetchWordChars()
 {
-  // Valid word characters:
-  std::regex rx(R"([a-z\d_])", std::regex_constants::icase);
-
-  return FetchCharsWhile([&rx](char c) { return std::regex_match(std::string(1, c), rx); });
+  return FetchCharsWhile([](char c) {
+    return std::isalpha(c, std::locale::classic()) || std::isdigit(c, std::locale::classic()) ||
+           c == '_';
+  });
 }
 
 Token Lexer::GetDelimitedLiteral()
@@ -134,7 +134,8 @@ Token Lexer::GetRealLiteral(char first_char)
   value += first_char;
   value += FetchCharsWhile([](char c) { return isdigit(c, std::locale::classic()) || ('.' == c); });
 
-  if (std::regex_match(value, std::regex(R"(\d+(\.\d+)?)")))
+  static const std::regex re(R"(\d+(\.\d+)?)");
+  if (std::regex_match(value, re))
     return Token(TOK_LITERAL, value);
 
   return Token(TOK_INVALID);
-- 
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