From dc2cd57a5a38b1f1d93c4062be340e421d74e004 Mon Sep 17 00:00:00 2001
From: Jan Travnicek <Jan.Travnicek@fit.cvut.cz>
Date: Thu, 19 Feb 2015 17:09:59 +0100
Subject: [PATCH] identities and nongenerative rules properly fix
---
alib2algo/src/grammar/simplify/LeftRecursionRemover.cpp | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/alib2algo/src/grammar/simplify/LeftRecursionRemover.cpp b/alib2algo/src/grammar/simplify/LeftRecursionRemover.cpp
index 3837b8ac91..d4c760831b 100644
--- a/alib2algo/src/grammar/simplify/LeftRecursionRemover.cpp
+++ b/alib2algo/src/grammar/simplify/LeftRecursionRemover.cpp
@@ -93,7 +93,7 @@ grammar::EpsilonFreeCFG assignAsOrder(const grammar::EpsilonFreeCFG& origGrammar
continue;
}
if(origGrammar.getRules().find(secondLHS) == origGrammar.getRules().end()) { //is there any right hand side to substitue with?
- res.addRule(lhs, singleRHS);
+ //if not well this rule does not generate anything anyway
continue;
}
@@ -109,6 +109,9 @@ grammar::EpsilonFreeCFG assignAsOrder(const grammar::EpsilonFreeCFG& origGrammar
grammar::EpsilonFreeCFG LeftRecursionRemover::remove(const grammar::EpsilonFreeCFG& origGrammar) {
grammar::EpsilonFreeCFG step = origGrammar;
+ for(const alphabet::Symbol& nonterminal : step.getNonterminalAlphabet()) { // remove identities
+ step.removeRule(nonterminal, std::vector<alphabet::Symbol>{nonterminal});
+ }
unsigned i = 0;
while(i < origGrammar.getNonterminalAlphabet().size()) {
grammar::EpsilonFreeCFG nextStep = assignAsOrder(directLeftRecursionRemoveAsOrder(step), i, origGrammar.getNonterminalAlphabet());
--
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