From 4b0e23f4cb4662b6a929a4b2346016875cfd8f84 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Pecka?= <peckato1@fit.cvut.cz>
Date: Sat, 22 Feb 2014 20:49:29 +0100
Subject: [PATCH] aLib: RegExp - method to check if regexp describes empty
language
---
alib/src/regexp/RegExp.cpp | 4 ++++
alib/src/regexp/RegExp.h | 5 +++++
2 files changed, 9 insertions(+)
diff --git a/alib/src/regexp/RegExp.cpp b/alib/src/regexp/RegExp.cpp
index 5730a96c30..b35657c0d9 100644
--- a/alib/src/regexp/RegExp.cpp
+++ b/alib/src/regexp/RegExp.cpp
@@ -70,6 +70,10 @@ void RegExp::setRegExp(RegExpElement* regExp) {
this->regExp = regExp;
}
+bool RegExp::isEmpty() const {
+ return regExp == NULL || dynamic_cast<const RegExpEmpty*>(regExp);
+}
+
void RegExp::toXML(ostream& out) {
RegExpPrinter::toXML(*this, out);
}
diff --git a/alib/src/regexp/RegExp.h b/alib/src/regexp/RegExp.h
index 19f25308bc..e31198ae94 100644
--- a/alib/src/regexp/RegExp.h
+++ b/alib/src/regexp/RegExp.h
@@ -55,6 +55,11 @@ public:
*/
void setRegExp(RegExpElement* regExp);
+ /**
+ * @return true if regexp represents empty language
+ */
+ bool isEmpty() const;
+
/**
* Prints XML representation of the RegExp to the output stream.
* @param out output stream to which print the RegExp
--
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