From 2f6885f273a105504ed8e1bcd91802e386b8fe2d Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Thu, 8 Sep 2022 18:14:52 +0000
Subject: [PATCH] Memoize lpeg patterns for keywords in script spec/rules

---
 nse_main.lua | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/nse_main.lua b/nse_main.lua
index f06edc1bb..9fc6b7b22 100644
--- a/nse_main.lua
+++ b/nse_main.lua
@@ -278,9 +278,14 @@ local function host_copy(t)
 end
 
 -- Return a pattern which matches a "keyword" literal, case insensitive.
+local memo_K = {}
 local function K (a)
-  local insensitize = Cf((P(1) / function (a) return S(lower(a)..upper(a)) end)^1, function (a, b) return a * b end);
-  return assert(insensitize:match(a)) * #(V "space" + S"()," + P(-1)); -- "keyword" token
+  local kw = memo_K[a]
+  if not kw then
+    kw = U.caseless(a) * #(V "space" + S"()," + P(-1))
+    memo_K[a] = kw
+  end
+  return kw
 end
 
 local REQUIRE_ERROR = {};