Adds LeftRegularGrammar

alib/src/grammar/LeftRegularGrammar.cpp

+/*
+ * LeftRegularGrammar.cpp
+ *
+ *  Created on: Nov 17, 2013
+ *      Author: martin
+ */
+
+#include "LeftRegularGrammar.h"
+
+namespace grammar {
+
+bool LeftRegularGrammar::isValidRule(const Rule& rule) const {
+	return checkLeftSide(rule.getLeftSide()) && checkRightSide(rule.getRightSide());
+}
+
+bool LeftRegularGrammar::checkLeftSide(const list<Symbol>& leftSide) const {
+	if (leftSide.size() != 1) {
+		return false;
+	}
+
+	if (nonTerminalSymbols.find(leftSide.front()) == nonTerminalSymbols.end()) {
+		return false;
+	}
+
+	return true;
+}
+
+bool LeftRegularGrammar::checkRightSide(const list<Symbol>& rightSide) const {
+	if (rightSide.size() == 0) {
+		return true;
+	} else if (rightSide.size() == 1) {
+		const Symbol& symbol = rightSide.front();
+
+		//check epsilon
+		if (symbol.getSymbol() == "") {
+			return true;
+		}
+
+		//check that symbol exists
+		return ((terminalSymbols.find(symbol) != terminalSymbols.end())
+				|| (nonTerminalSymbols.find(symbol) != nonTerminalSymbols.end()));
+	} else {
+		//check if first symbol is nonterminal
+		list<Symbol>::const_iterator symbol = rightSide.begin();
+		if (nonTerminalSymbols.find(*symbol) == nonTerminalSymbols.end()) {
+			return false;
+		}
+
+		symbol++;
+
+		//check if following symbols are terminal
+		for (; symbol != rightSide.end(); symbol++) {
+			if (terminalSymbols.find(*symbol) == terminalSymbols.end()) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+}
+
+} /* namespace grammar */

alib/src/grammar/LeftRegularGrammar.h

+/*
+ * LeftRegularGrammar.h
+ *
+ *  Created on: Nov 17, 2013
+ *      Author: martin
+ */
+
+#ifndef LEFTREGULARGRAMMAR_H_
+#define LEFTREGULARGRAMMAR_H_
+
+#include "Grammar.h"
+
+namespace grammar {
+
+class LeftRegularGrammar : public Grammar {
+private:
+	bool checkLeftSide(const list<Symbol>& leftSide) const;
+	bool checkRightSide(const list<Symbol>& rightSide) const;
+protected:
+	bool isValidRule(const Rule& rule) const;
+};
+
+} /* namespace grammar */
+#endif /* LEFTREGULARGRAMMAR_H_ */

examples/grammar/leftRegular.xml

+<grammar>
+	<nonTerminalSymbols>
+		<symbol>S</symbol>
+		<symbol>A</symbol>
+	</nonTerminalSymbols>
+
+	<terminalSymbols>
+		<symbol>a</symbol>
+		<symbol>b</symbol>
+	</terminalSymbols>
+
+	<rules>
+		<rule>
+			<leftSide>
+				<symbol>S</symbol>
+			</leftSide>
+
+			<rightSide>
+				<symbol>A</symbol>
+			</rightSide>
+		</rule>
+		<rule>
+			<leftSide>
+				<symbol>A</symbol>
+			</leftSide>
+
+			<rightSide>
+				<symbol>a</symbol>
+			</rightSide>
+		</rule>
+		<rule>
+			<leftSide>
+				<symbol>A</symbol>
+			</leftSide>
+			<rightSide>
+				<symbol>A</symbol>
+				<symbol>b</symbol>
+				<symbol>b</symbol>
+				<symbol>b</symbol>
+			</rightSide>
+		</rule>
+	</rules>
+
+	<startSymbol>S</startSymbol>
+	
+</grammar>