From ec7f8d5ab9868a05504d36ee56b96d778b70505a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Chocholat=C3=BD?= <chocholaty.david@protonmail.com>
Date: Wed, 21 Feb 2024 06:29:32 +0100
Subject: [PATCH] Explain where bit vector implementation has shortcomings

---
 src/nfa/delta.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/nfa/delta.cc b/src/nfa/delta.cc
index f0aa39d5..7291f608 100644
--- a/src/nfa/delta.cc
+++ b/src/nfa/delta.cc
@@ -548,6 +548,8 @@ OrdVector<Symbol> Delta::get_used_symbols() const {
     //return utils::OrdVector<Symbol>(utils::NumberPredicate<Symbol>(get_used_symbols_bv()));
 
     //WITH BOOL VECTOR (1.9s): (The fastest, it seems.)
+    // However, it will try to allocate a vector indexed by the symbols. If there are epsilons in the automaton,
+    //  for example, the bool vector implementation will implode.
     // std::vector<bool> bv{ get_used_symbols_bv() };
     // utils::OrdVector<Symbol> ov{};
     // const size_t bv_size{ bv.size() };
@@ -649,7 +651,6 @@ std::vector<bool> Delta::get_used_symbols_bv() const {
             symbols[symbol_post.symbol] = true;
         }
     }
-    //TODO: is it neccessary toreturn ordered vector? Would the number predicate suffice?
     return symbols;
 }