From 8635c06a169acdcebbd29bc6c615262bc5a6c73d Mon Sep 17 00:00:00 2001
From: Martin Zak <zakmart1@fit.cvut.cz>
Date: Sun, 17 Nov 2013 17:06:41 +0100
Subject: [PATCH] Grammar refactoring
---
alib/src/grammar/Grammar.cpp | 28 +++++-------
alib/src/grammar/Grammar.h | 6 +--
alib/src/grammar/RightRegularGrammar.cpp | 45 +++++++------------
alib/src/grammar/RightRegularGrammar.h | 4 +-
alib/src/grammar/UnknownGrammar.cpp | 19 +++++---
alib/src/grammar/UnknownGrammar.h | 4 +-
.../grammar/{regular.xml => rightRegular.xml} | 12 +++++
7 files changed, 58 insertions(+), 60 deletions(-)
rename examples/grammar/{regular.xml => rightRegular.xml} (68%)
diff --git a/alib/src/grammar/Grammar.cpp b/alib/src/grammar/Grammar.cpp
index 4b02480f47..f76c90ce1c 100644
--- a/alib/src/grammar/Grammar.cpp
+++ b/alib/src/grammar/Grammar.cpp
@@ -14,24 +14,6 @@ namespace grammar {
using namespace std;
using namespace alphabet;
-bool Grammar::usesExistingSymbols(const Rule& rule) const{
- const list<Symbol>& leftSide = rule.getLeftSide();
- for(list<Symbol>::const_iterator left = leftSide.begin(); left != leftSide.end(); left ++) {
- if(terminalSymbols.find(*left) == terminalSymbols.end() && nonTerminalSymbols.find(*left) == nonTerminalSymbols.end()) {
- return false;
- }
- }
-
- const list<Symbol>& rightSide = rule.getRightSide();
- for(list<Symbol>::const_iterator right = rightSide.begin(); right != rightSide.end(); right++) {
- if(terminalSymbols.find(*right) == terminalSymbols.end() && nonTerminalSymbols.find(*right) == nonTerminalSymbols.end()) {
- return false;
- }
- }
-
- return true;
-}
-
Grammar::~Grammar() {
}
@@ -109,6 +91,16 @@ void Grammar::setStartSymbol(const Symbol& symbol) {
startSymbol = symbol;
}
+void Grammar::addRule(const Rule& rule) {
+ if (!isValidRule(rule)) {
+ throw GrammarException("Rule is not valid for this grammar.");
+ }
+
+ if (!rules.insert(rule).second) {
+ throw GrammarException("Rule already exists.");
+ }
+}
+
void Grammar::toXML(ostream& out) const {
GrammarPrinter::toXML(*this, out);
}
diff --git a/alib/src/grammar/Grammar.h b/alib/src/grammar/Grammar.h
index a16c91bce0..33fbe2e64f 100644
--- a/alib/src/grammar/Grammar.h
+++ b/alib/src/grammar/Grammar.h
@@ -26,7 +26,7 @@ protected:
set<Rule> rules;
Symbol startSymbol;
- bool usesExistingSymbols(const Rule& rule) const;
+ virtual bool isValidRule(const Rule& rule) const = 0;
public:
virtual ~Grammar();
@@ -38,14 +38,14 @@ public:
void removeNonTerminalSymbol(const Symbol& symbol);
const set<Symbol>& getNonTerminalSymbols() const;
- virtual void addRule(const Rule& rule) = 0;
+ void addRule(const Rule& rule);
void removeRule(const Rule& rule);
const set<Rule>& getRules() const;
const Symbol& getStartSymbol() const;
void setStartSymbol(const Symbol& symbol);
- virtual void toXML(ostream& out) const;
+ void toXML(ostream& out) const;
};
} /* namespace grammar */
diff --git a/alib/src/grammar/RightRegularGrammar.cpp b/alib/src/grammar/RightRegularGrammar.cpp
index 2f7b4c5c89..fb552d648c 100644
--- a/alib/src/grammar/RightRegularGrammar.cpp
+++ b/alib/src/grammar/RightRegularGrammar.cpp
@@ -11,18 +11,8 @@
namespace grammar {
-void RightRegularGrammar::addRule(const Rule& rule) {
- if (!isValidRule(rule)) {
- throw GrammarException("Not a right regular grammar rule.");
- }
-
- if (!rules.insert(rule).second) {
- throw GrammarException("Rule already exists.");
- }
-}
-
bool RightRegularGrammar::isValidRule(const Rule& rule) const {
- return usesExistingSymbols(rule) && checkLeftSide(rule.getLeftSide()) && checkRightSide(rule.getRightSide());
+ return checkLeftSide(rule.getLeftSide()) && checkRightSide(rule.getRightSide());
}
bool RightRegularGrammar::checkLeftSide(const list<Symbol>& leftSide) const {
@@ -40,9 +30,7 @@ bool RightRegularGrammar::checkLeftSide(const list<Symbol>& leftSide) const {
bool RightRegularGrammar::checkRightSide(const list<Symbol>& rightSide) const {
if (rightSide.size() == 0) {
return true;
- }
-
- if (rightSide.size() == 1) {
+ } else if (rightSide.size() == 1) {
const Symbol& symbol = rightSide.front();
//check epsilon
@@ -50,27 +38,26 @@ bool RightRegularGrammar::checkRightSide(const list<Symbol>& rightSide) const {
return true;
}
- if (terminalSymbols.find(symbol) == terminalSymbols.end()
- && nonTerminalSymbols.find(symbol) == nonTerminalSymbols.end()) {
- return false;
+ //check that symbol exists
+ return ((terminalSymbols.find(symbol) != terminalSymbols.end())
+ || (nonTerminalSymbols.find(symbol) != nonTerminalSymbols.end()));
+
+ } else {
+ //check if all symbols except the last one are terminal symbols
+ for (list<Symbol>::const_iterator symbol = rightSide.begin(); symbol != --rightSide.end(); symbol++) {
+ if (terminalSymbols.find(*symbol) == terminalSymbols.end()) {
+ return false;
+ }
}
- return true;
- }
- //check if all symbols except the last are terminal symbols
- for (list<Symbol>::const_iterator symbol = rightSide.begin(); symbol != --rightSide.end(); symbol++) {
- if (terminalSymbols.find(*symbol) == terminalSymbols.end()) {
+ //check if last symbol is nonterminal
+ const Symbol& lastSymbol = *(--rightSide.end());
+ if (nonTerminalSymbols.find(lastSymbol) == nonTerminalSymbols.end()) {
return false;
}
- }
- //check if last symbol is nonterminal
- const Symbol& lastSymbol = *(--rightSide.end());
- if (nonTerminalSymbols.find(lastSymbol) == nonTerminalSymbols.end()) {
- return false;
+ return true;
}
-
- return true;
}
}
diff --git a/alib/src/grammar/RightRegularGrammar.h b/alib/src/grammar/RightRegularGrammar.h
index 46a8e52eb4..deffa166ec 100644
--- a/alib/src/grammar/RightRegularGrammar.h
+++ b/alib/src/grammar/RightRegularGrammar.h
@@ -12,14 +12,12 @@
namespace grammar {
-class RightRegularGrammar: public grammar::Grammar {
+class RightRegularGrammar: public Grammar {
private:
bool checkLeftSide(const list<Symbol>& leftSide) const;
bool checkRightSide(const list<Symbol>& rightSide) const;
public:
bool isValidRule(const Rule& rule) const;
- void addRule(const Rule& rule);
-
};
} /* namespace grammar */
diff --git a/alib/src/grammar/UnknownGrammar.cpp b/alib/src/grammar/UnknownGrammar.cpp
index 19b02d82f8..ae89e343dc 100644
--- a/alib/src/grammar/UnknownGrammar.cpp
+++ b/alib/src/grammar/UnknownGrammar.cpp
@@ -10,14 +10,23 @@
namespace grammar {
-void UnknownGrammar::addRule(const Rule& rule) {
- usesExistingSymbols(rule);
+bool UnknownGrammar::isValidRule(const Rule& rule) const {
+ for (auto const & symbol : rule.getLeftSide()) {
+ if (terminalSymbols.find(symbol) == terminalSymbols.end()
+ && nonTerminalSymbols.find(symbol) == nonTerminalSymbols.end()) {
+ return false;
+ }
+ }
- if(!rules.insert(rule).second) {
- throw GrammarException("Rule already exists.");
+ for (auto const & right : rule.getRightSide()) {
+ if (terminalSymbols.find(right) == terminalSymbols.end()
+ && nonTerminalSymbols.find(right) == nonTerminalSymbols.end()) {
+ return false;
+ }
}
+
+ return true;
}
} /* namespace grammar */
-
diff --git a/alib/src/grammar/UnknownGrammar.h b/alib/src/grammar/UnknownGrammar.h
index a3f1829589..8f03a98ff7 100644
--- a/alib/src/grammar/UnknownGrammar.h
+++ b/alib/src/grammar/UnknownGrammar.h
@@ -13,8 +13,8 @@
namespace grammar {
class UnknownGrammar: public grammar::Grammar {
-public:
- void addRule(const Rule& rule);
+protected:
+ bool isValidRule(const Rule& rule) const;
};
} /* namespace grammar */
diff --git a/examples/grammar/regular.xml b/examples/grammar/rightRegular.xml
similarity index 68%
rename from examples/grammar/regular.xml
rename to examples/grammar/rightRegular.xml
index 18e5614bb0..1e3f164c41 100644
--- a/examples/grammar/regular.xml
+++ b/examples/grammar/rightRegular.xml
@@ -6,6 +6,7 @@
<terminalSymbols>
<symbol>a</symbol>
+ <symbol>b</symbol>
</terminalSymbols>
<rules>
@@ -27,6 +28,17 @@
<symbol>a</symbol>
</rightSide>
</rule>
+ <rule>
+ <leftSide>
+ <symbol>A</symbol>
+ </leftSide>
+ <rightSide>
+ <symbol>b</symbol>
+ <symbol>b</symbol>
+ <symbol>b</symbol>
+ <symbol>A</symbol>
+ </rightSide>
+ </rule>
</rules>
<startSymbol>S</startSymbol>
--
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