From 60f476a7d09236d570654506803397acb4691051 Mon Sep 17 00:00:00 2001
From: Fangyi Zhou <me@fangyi.io>
Date: Fri, 3 Dec 2021 21:46:23 +0000
Subject: [PATCH] Fix exponential time behaviour when constructing Alt (#106)

Fixes #97 by removing a duplicate evaluation

Signed-off-by: Fangyi Zhou <fangyi.zhou15@imperial.ac.uk>
---
 src/syntax/sedlex.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/syntax/sedlex.ml b/src/syntax/sedlex.ml
index aeb42d36..4ff7f765 100644
--- a/src/syntax/sedlex.ml
+++ b/src/syntax/sedlex.ml
@@ -38,7 +38,7 @@ let alt r1 r2 succ =
   | Some c1, Some c2 -> chars (Cset.union c1 c2) succ
   | _ ->
     let n = new_node () in
-    n.eps <- [r1 succ; r2 succ];
+    n.eps <- [nr1; nr2];
     n
 
 let rep r succ =