diff --git a/include/Lexesis/re.h b/include/Lexesis/re.h
index 9671a30..6625339 100644
--- a/include/Lexesis/re.h
+++ b/include/Lexesis/re.h
@@ -4,6 +4,7 @@
#include "Lexesis/automata.h"
+#include <memory>
#include <stdexcept>
namespace lxs {
@@ -11,7 +12,7 @@ namespace lxs {
{
public:
virtual ~RE() {}
- virtual int toENFA(ENFA& enfa, int attach) = 0;
+ virtual State toENFA(ENFA& enfa, State attach) = 0;
virtual std::string toRe() = 0;
};
@@ -20,7 +21,7 @@ namespace lxs {
public:
EmptyRE() {}
~EmptyRE() {}
- virtual int toENFA(ENFA& enfa, int attach);
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
};
@@ -29,7 +30,7 @@ namespace lxs {
public:
EpsilonRE() {}
~EpsilonRE() {}
- virtual int toENFA(ENFA& enfa, int attach);
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
};
@@ -38,7 +39,7 @@ namespace lxs {
public:
SingleRE(char c) : c(c) {}
~SingleRE() {}
- virtual int toENFA(ENFA& enfa, int attach);
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
char c;
@@ -47,37 +48,37 @@ namespace lxs {
class ConcatRE : public RE
{
public:
- ConcatRE(RE* e, RE* f) : e(e), f(f) {}
- ~ConcatRE() {delete e; delete f;}
- virtual int toENFA(ENFA& enfa, int attach);
+ ConcatRE(std::shared_ptr<RE> e, std::shared_ptr<RE> f) : e(e), f(f) {}
+ ~ConcatRE() {}
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
- RE* e, *f;
+ std::shared_ptr<RE> e, f;
};
class StarRE : public RE
{
public:
- StarRE(RE* e) : e(e) {}
- ~StarRE() {delete e;}
- virtual int toENFA(ENFA& enfa, int attach);
+ StarRE(std::shared_ptr<RE> e) : e(e) {}
+ ~StarRE() {}
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
- RE* e;
+ std::shared_ptr<RE> e;
};
class PlusRE : public RE
{
public:
- PlusRE(RE* e, RE* f) : e(e), f(f) {}
- ~PlusRE() {delete e; delete f;}
- virtual int toENFA(ENFA& enfa, int attach);
+ PlusRE(std::shared_ptr<RE> e, std::shared_ptr<RE> f) : e(e), f(f) {}
+ ~PlusRE() {}
+ virtual State toENFA(ENFA& enfa, State attach);
virtual std::string toRe();
- RE* e, *f;
+ std::shared_ptr<RE> e, f;
};
- RE* parseRE(std::string& input);
+ std::shared_ptr<RE> parseRE(std::string& input);
class SyntaxError : public std::runtime_error
{
diff --git a/src/re.cpp b/src/re.cpp
index e884ae4..63e4e40 100644
--- a/src/re.cpp
+++ b/src/re.cpp
@@ -97,51 +97,41 @@ namespace lxs {
return b + 1;
}
- static void compress(stack<RE*>& stk)
- {
- RE* a = stk.top();
- stk.pop();
- RE* b = stk.top();
- stk.pop();
- stk.push(new ConcatRE(b, a)); //Attention: reversed order because of stack
- }
-
- static void compactStack(stack<RE*>& stk)
- {
- if (stk.empty()) return;
- RE* tp = stk.top();
- stk.pop();
- while (stk.size() >= 2)
- {
- compress(stk);
- }
- stk.push(tp);
- }
-
namespace {
- RE* parseRE(string& input, size_t& idx)
+ void compress(stack<std::shared_ptr<RE>>& stk)
{
- stack<RE*> stk;
+ std::shared_ptr<RE> a = stk.top();
+ stk.pop();
+ std::shared_ptr<RE> b = stk.top();
+ stk.pop();
+ stk.push(std::make_shared<ConcatRE>(b, a)); //Attention: reversed order because of stack
+ }
+
+ void compactStack(stack<std::shared_ptr<RE> >& stk)
+ {
+ if (stk.empty()) return;
+ std::shared_ptr<RE> tp = stk.top();
+ stk.pop();
+ while (stk.size() >= 2)
+ {
+ compress(stk);
+ }
+ stk.push(tp);
+ }
+
+ std::shared_ptr<RE> parseRE(string& input, size_t& idx)
+ {
+ stack<std::shared_ptr<RE> > stk;
for (; idx < input.length(); idx++)
{
- RE* n;
+ std::shared_ptr<RE> n;
switch (input[idx])
{
- case '\n':
- if (idx != input.size() - 1)
- throw SyntaxError("Cannot have a newline inside of a regex");
- break;
-
case '\\':
idx++;
if (idx >= input.length())
throw SyntaxError("Escape sequence at the end of the string");
- if (input[idx] == 'e')
- stk.push(new EpsilonRE());
- else if (input[idx] == 'E')
- stk.push(new EmptyRE());
- else if (input[idx] == '\\' || input[idx] == '*' || input[idx] == '+' || input[idx] == '(' || input[idx] == ')')
- stk.push(new SingleRE(input[idx]));
+ //TODO: escape chars
else
throw SyntaxError(("invalid escape sequence: \\" + string(1, input[idx])).c_str());
break;
@@ -149,19 +139,34 @@ namespace lxs {
case '*':
if (stk.empty())
throw SyntaxError("Cannot apply kleene star to empty regex");
- n = new StarRE(stk.top());
+ n = std::make_shared<StarRE>(stk.top());
stk.pop();
stk.push(n);
break;
case '+':
if (stk.empty())
- throw SyntaxError("Invalid regex: nothing to the left of '+'");
+ throw SyntaxError("Cannot apply kleene plus to empty regex");
+ n = stk.top();
+ stk.pop();
+ n = std::make_shared<ConcatRE>(n, std::make_shared<StarRE>(n));
+ stk.push(n);
+ break;
+
+ case '?':
+ if (stk.empty())
+ throw SyntaxError("Cannot apply '?' to empty regex");
+ n = std::make_shared<PlusRE>(stk.top(), std::make_shared<EpsilonRE>());
+ stk.pop();
+ stk.push(n);
+ break;
+
+ case '|':
+ if (stk.empty())
+ throw SyntaxError("Invalid regex: nothing to the left of '|'");
if (stk.size() > 1)
compactStack(stk), compress(stk);
- n = new PlusRE(nullptr, nullptr);
- ((PlusRE*) n)->e = stk.top();
- ((PlusRE*) n)->f = parseRE(input, ++idx);
+ n = std::make_shared<PlusRE>(stk.top(), parseRE(input, ++idx));
stk.pop();
stk.push(n);
idx--;
@@ -182,7 +187,7 @@ namespace lxs {
throw SyntaxError("Could not parse regex, nothing inside parentheses");
default:
- stk.push(new SingleRE(input[idx]));
+ stk.push(std::make_shared<SingleRE>(input[idx]));
}
compactStack(stk);
}
@@ -195,10 +200,10 @@ namespace lxs {
}
- RE* parseRE(string& input)
+ std::shared_ptr<RE> parseRE(string& input)
{
size_t i = 0;
- RE* res = parseRE(input, i);
+ std::shared_ptr<RE> res = parseRE(input, i);
if (i < input.length() - 1)
throw SyntaxError("Incorrect regex");
return res;