Implement variables (prefixed strings to find values elsewhere)

25 files changed, 284 insertions, 104 deletions

diff --git a/project2/appEngine.cpp b/project2/appEngine.cpp
index 632bb11..be49c10 100644
--- a/project2/appEngine.cpp
+++ b/project2/appEngine.cpp
@@ -1,10 +1,18 @@
 #include "appEngine.h"
+#include <stdexcept>
+
+ApplicationEngine * ApplicationEngine::currentEngine = NULL;
 
 ApplicationEngine::ApplicationEngine(const Environment *)
 {
+	if (currentEngine) {
+		throw std::runtime_error("One application at a time, please");
+	}
+	currentEngine = this;
 }
 
 ApplicationEngine::~ApplicationEngine()
 {
+	currentEngine = NULL;
 }
 
diff --git a/project2/appEngine.h b/project2/appEngine.h
index d2cff10..59e0d4d 100644
--- a/project2/appEngine.h
+++ b/project2/appEngine.h
@@ -3,6 +3,7 @@
 
 #include "environment.h"
 #include "dataSource.h"
+#include "session.h"
 
 class ApplicationEngine {
 	public:
@@ -14,8 +15,7 @@ class ApplicationEngine {
 
 		virtual void process() const = 0;
 		virtual const Environment * env() const = 0;
-		virtual void SessionSet(const Glib::ustring & name, const Glib::ustring & value) const = 0;
-		virtual void SessionClear(const Glib::ustring & name) const = 0;
+		virtual SessionPtr session() const = 0;
 
 		template <class DataSourceType>
 		const DataSourceType * dataSource(const std::string & name) const
@@ -30,8 +30,11 @@ class ApplicationEngine {
 			}
 			return s;
 		}
+		static ApplicationEngine * getCurrent() { return currentEngine; }
 	protected:
 		mutable DataSources datasources;
+	private:
+		static ApplicationEngine * currentEngine;
 };
 
 #endif
diff --git a/project2/cgiAppEngine.cpp b/project2/cgiAppEngine.cpp
index 60b1ed3..a419be0 100644
--- a/project2/cgiAppEngine.cpp
+++ b/project2/cgiAppEngine.cpp
@@ -185,14 +185,9 @@ CgiApplicationEngine::RequestStage::run()
 	return new PresentStage(appEngine, present);
 }
 
-void
-CgiApplicationEngine::SessionSet(const Glib::ustring & name, const Glib::ustring & value) const
-{
-	sessionsContainer->GetSession(sessionID)->SetValue(name, value);
-}
-void
-CgiApplicationEngine::SessionClear(const Glib::ustring & name) const
+SessionPtr
+CgiApplicationEngine::session() const
 {
-	sessionsContainer->GetSession(sessionID)->ClearValue(name);
+	return sessionsContainer->GetSession(sessionID);
 }
 
diff --git a/project2/cgiAppEngine.h b/project2/cgiAppEngine.h
index f6f37d0..0172eee 100644
--- a/project2/cgiAppEngine.h
+++ b/project2/cgiAppEngine.h
@@ -10,6 +10,7 @@
 #include <libxml++/parsers/domparser.h>
 
 class CgiEnvironment;
+class Session;
 namespace cgicc {
 	class HTTPContentHeader;
 }
@@ -26,8 +27,7 @@ class CgiApplicationEngine : public ApplicationEngine {
 			w(doc->cobj());
 		}
 		const Environment * env() const;
-		virtual void SessionSet(const Glib::ustring & name, const Glib::ustring & value) const;
-		virtual void SessionClear(const Glib::ustring & name) const;
+		SessionPtr session() const;
 		const CgiEnvironment * _env;
 	protected:
 		cgicc::HTTPContentHeader * header;
diff --git a/project2/iHaveParameters.cpp b/project2/iHaveParameters.cpp
index c13eddf..0f1084e 100644
--- a/project2/iHaveParameters.cpp
+++ b/project2/iHaveParameters.cpp
@@ -18,8 +18,7 @@ IHaveParameters::~IHaveParameters()
 }
 
 IHaveParameters::_Parameter::_Parameter(const xmlpp::Element * p) :
-	source(p->get_attribute_value("source")),
-	id(p->get_attribute_value("id")),
+	value(p->get_attribute("value")),
 	bind(atoi(p->get_attribute_value("bind").c_str()))
 {
 }
diff --git a/project2/iHaveParameters.h b/project2/iHaveParameters.h
index 31c597a..329e341 100644
--- a/project2/iHaveParameters.h
+++ b/project2/iHaveParameters.h
@@ -3,14 +3,14 @@
 
 #include <libxml++/nodes/element.h>
 #include <boost/shared_ptr.hpp>
+#include "variables.h"
 
 class IHaveParameters {
 	public:
 		class _Parameter {
 			public:
 				_Parameter(const xmlpp::Element * p);
-				const std::string source;
-				const std::string id;
+				const Variable value;
 				const unsigned int bind;
 		};
 		IHaveParameters(const xmlpp::Element * p);
diff --git a/project2/iterate.cpp b/project2/iterate.cpp
index 02fc149..843d598 100644
--- a/project2/iterate.cpp
+++ b/project2/iterate.cpp
@@ -34,8 +34,16 @@ _Iterate::AddLoaders(Loaders & l, NoOutputExecutes & iterates)
 void
 _Iterate::executeChildren(const ApplicationEngine * ep, const PerRowValues * parent) const
 {
-	BOOST_FOREACH(NoOutputExecutes::value_type sq, subIterates) {
-		sq.second->execute(ep, this);
+	try {
+		PerRowValues::beginRow(this);
+		BOOST_FOREACH(NoOutputExecutes::value_type sq, subIterates) {
+			sq.second->execute(ep, this);
+		}
+		PerRowValues::endRow(this);
+	}
+	catch (...) {
+		PerRowValues::endRow(this);
+		throw;
 	}
 }
 
diff --git a/project2/paramChecker.cpp b/project2/paramChecker.cpp
index 627f1be..5455f22 100644
--- a/project2/paramChecker.cpp
+++ b/project2/paramChecker.cpp
@@ -7,7 +7,6 @@
 _ParamChecker::_ParamChecker(const xmlpp::Element * p) :
 	_SourceObject(p),
 	message(xmlChildText(p, "message")),
-	applyTo(p->get_attribute_value("apply-to")),
 	present(p->get_attribute_value("present"))
 {
 }
diff --git a/project2/paramChecker.h b/project2/paramChecker.h
index 1ffe89f..b22a1f9 100644
--- a/project2/paramChecker.h
+++ b/project2/paramChecker.h
@@ -6,6 +6,7 @@
 #include <map>
 #include "sourceObject.h"
 #include "xmlObjectLoader.h"
+#include "variables.h"
 
 class ApplicationEngine;
 class _ParamChecker;
@@ -21,7 +22,6 @@ class _ParamChecker : public virtual _SourceObject {
 		virtual bool performCheck(const ApplicationEngine *) const = 0;
 
 		const Glib::ustring message;
-		const std::string applyTo;
 		const std::string present;
 
 		static void AddLoaders(Loaders & l, OrderedParamCheckers & vs);
diff --git a/project2/perRowValues.cpp b/project2/perRowValues.cpp
new file mode 100644
index 0000000..30433fd
--- /dev/null
+++ b/project2/perRowValues.cpp
@@ -0,0 +1,28 @@
+#include "perRowValues.h"
+#include <cstdlib>
+
+PerRowValues::RowValuesStack PerRowValues::stack;
+
+PerRowValues::PerRowValues()
+{
+}
+
+PerRowValues::~PerRowValues()
+{
+}
+
+void
+PerRowValues::beginRow(const PerRowValues * r)
+{
+	stack.push_back(r);
+}
+
+void
+PerRowValues::endRow(const PerRowValues * r)
+{
+	if ((*stack.rbegin()) != r) {
+		std::abort();
+	}
+	stack.pop_back();
+}
+
diff --git a/project2/perRowValues.h b/project2/perRowValues.h
index 2a46763..eec8e37 100644
--- a/project2/perRowValues.h
+++ b/project2/perRowValues.h
@@ -2,10 +2,21 @@
 #define PERROWVALUES_H
 
 #include <glibmm/ustring.h>
+#include <vector>
 
 class PerRowValues {
 	public:
+		typedef std::vector<const PerRowValues *> RowValuesStack;
+		PerRowValues();
+		virtual ~PerRowValues() = 0;
+
 		virtual Glib::ustring getCurrentValue(const Glib::ustring & id) const = 0;
+		static const RowValuesStack & Stack() { return stack; }
+		static void beginRow(const PerRowValues * r);
+		static void endRow(const PerRowValues * r);
+
+	private:
+		static RowValuesStack stack;
 };
 
 #endif
diff --git a/project2/regexCheck.cpp b/project2/regexCheck.cpp
index 672194f..d6e1bb0 100644
--- a/project2/regexCheck.cpp
+++ b/project2/regexCheck.cpp
@@ -6,6 +6,7 @@
 _RegexCheck::_RegexCheck(const xmlpp::Element * p) :
 	_SourceObject(p),
 	_ParamChecker(p),
+	applyTo(p->get_attribute("apply-to")),
 	regex(xmlChildText(p, "regex").raw())
 {
 }
@@ -17,7 +18,7 @@ _RegexCheck::~_RegexCheck()
 bool
 _RegexCheck::performCheck(const ApplicationEngine * ep) const
 {
-	const Glib::ustring & param = ep->env()->getParamQuery(applyTo);
+	const Glib::ustring & param(applyTo);
 	return boost::regex_match(param.begin(), param.end(), regex);
 }
 
diff --git a/project2/regexCheck.h b/project2/regexCheck.h
index 5db92f5..b515d54 100644
--- a/project2/regexCheck.h
+++ b/project2/regexCheck.h
@@ -11,6 +11,7 @@ class _RegexCheck : public _ParamChecker {
 
 		bool performCheck(const ApplicationEngine *) const;
 
+		const Variable applyTo;
 		const boost::regex regex;
 };
 typedef boost::shared_ptr<_RegexCheck> RegexCheck;
diff --git a/project2/sessionClearTask.cpp b/project2/sessionClearTask.cpp
index 963ebeb..696f250 100644
--- a/project2/sessionClearTask.cpp
+++ b/project2/sessionClearTask.cpp
@@ -2,6 +2,7 @@
 #include "xmlObjectLoader.h"
 #include "sessionClearTask.h"
 #include "appEngine.h"
+#include "session.h"
 
 _SessionClearTask::_SessionClearTask(const xmlpp::Element * p) :
 	_SourceObject(p),
@@ -17,6 +18,6 @@ _SessionClearTask::~_SessionClearTask()
 void
 _SessionClearTask::execute(const ApplicationEngine * ep, const PerRowValues *) const
 {
-	ep->SessionClear(key);
+	ep->session()->ClearValue(key);
 }
 
diff --git a/project2/sessionSetTask.cpp b/project2/sessionSetTask.cpp
index abd02b0..8304494 100644
--- a/project2/sessionSetTask.cpp
+++ b/project2/sessionSetTask.cpp
@@ -3,12 +3,13 @@
 #include "xmlObjectLoader.h"
 #include "sessionSetTask.h"
 #include "appEngine.h"
+#include "session.h"
 
 _SessionSetTask::_SessionSetTask(const xmlpp::Element * p) :
 	_SourceObject(p),
 	_Task(p),
-	IHaveParameters(p),
-	key(p->get_attribute_value("key"))
+	key(p->get_attribute_value("key")),
+	value(p->get_attribute("value"))
 {
 }
 
@@ -19,15 +20,6 @@ _SessionSetTask::~_SessionSetTask()
 void
 _SessionSetTask::execute(const ApplicationEngine * ep, const PerRowValues * parent) const
 {
-	Parameter p = parameters.find(0)->second;
-	if (p->source == "uri") {
-		ep->SessionSet(key, ep->env()->getParamUri(p->id));
-	}
-	else if (p->source == "parent") {
-		ep->SessionSet(key, parent->getCurrentValue(p->id));
-	}
-	else if (p->source == "query") {
-		ep->SessionSet(key, ep->env()->getParamQuery(p->id));
-	}
+	ep->session()->SetValue(key, value);
 }
 
diff --git a/project2/sessionSetTask.h b/project2/sessionSetTask.h
index 32df37b..491c55d 100644
--- a/project2/sessionSetTask.h
+++ b/project2/sessionSetTask.h
@@ -7,19 +7,20 @@
 #include "sourceObject.h"
 #include "xmlObjectLoader.h"
 #include "task.h"
-#include "iHaveParameters.h"
+#include "variables.h"
 
 class ApplicationEngine;
 class _SessionSetTask;
 typedef boost::shared_ptr<_SessionSetTask> SessionSetTask;
 
-class _SessionSetTask : public virtual _Task, public IHaveParameters {
+class _SessionSetTask : public virtual _Task {
 	public:
 		_SessionSetTask(const xmlpp::Element * p);
 		virtual ~_SessionSetTask();
 		void execute(const ApplicationEngine *, const PerRowValues * parent = NULL) const;
 
 		const Glib::ustring key;
+		const Variable value;
 };
 
 #endif
diff --git a/project2/sqlCheck.cpp b/project2/sqlCheck.cpp
index 1dab147..65cf0e3 100644
--- a/project2/sqlCheck.cpp
+++ b/project2/sqlCheck.cpp
@@ -26,12 +26,7 @@ _SqlCheck::performCheck(const ApplicationEngine * ep) const
 {
 	ODBC::SelectCommand * query = new ODBC::SelectCommand(ep->dataSource<_RdbmsDataSource>(dataSource)->getReadonly(), sql);
 	BOOST_FOREACH(Parameters::value_type p, parameters) {
-		if (p.second->source == "uri") {
-			query->bindParamS(p.second->bind, ep->env()->getParamUri(p.second->id));
-		}
-		else if (p.second->source == "query") {
-			query->bindParamS(p.second->bind, ep->env()->getParamQuery(p.second->id));
-		}
+		query->bindParamS(p.second->bind, p.second->value);
 	}
 	bool retVal = false;
 	while (query->fetch()) {
diff --git a/project2/sqlIterate.cpp b/project2/sqlIterate.cpp
index 90a8bc1..5499940 100644
--- a/project2/sqlIterate.cpp
+++ b/project2/sqlIterate.cpp
@@ -25,32 +25,11 @@ _SqlIterate::getCurrentValue(const Glib::ustring & id) const
 	return (*query)[id].compose();
 }
 
-void
-_SqlIterate::rebindCurrentValue(const Glib::ustring & id, ODBC::Command * cmd, unsigned int bind) const
-{
-	(*query)[id].rebind(cmd, bind);
-}
-
 void _SqlIterate::execute(const ApplicationEngine * ep, const PerRowValues * parent) const
 {
-	typedef std::map<std::string, xmlpp::Element *> Columns;
 	query = new ODBC::SelectCommand(ep->dataSource<_RdbmsDataSource>(dataSource)->getReadonly(), sql);
 	BOOST_FOREACH(Parameters::value_type p, parameters) {
-		if (p.second->source == "uri") {
-			query->bindParamS(p.second->bind, ep->env()->getParamUri(p.second->id));
-		}
-		else if (p.second->source == "query") {
-			query->bindParamS(p.second->bind, ep->env()->getParamQuery(p.second->id));
-		}
-		else if (parent && p.second->source == "parent") {
-			const _SqlIterate * psqlIterate = dynamic_cast<const _SqlIterate *>(parent);
-			if (psqlIterate) {
-				psqlIterate->rebindCurrentValue(p.second->id, query, p.second->bind);
-			}
-			else {
-				query->bindParamS(p.second->bind, parent->getCurrentValue(p.second->id));
-			}
-		}
+		query->bindParamS(p.second->bind, p.second->value());
 	}
 	while (query->fetch()) {
 		executeChildren(ep, this);
diff --git a/project2/sqlIterate.h b/project2/sqlIterate.h
index c9cef49..41b5648 100644
--- a/project2/sqlIterate.h
+++ b/project2/sqlIterate.h
@@ -18,7 +18,7 @@ class _SqlIterate : public IHaveParameters, public _Iterate {
 		Glib::ustring getCurrentValue(const Glib::ustring & id) const;
 		const std::string dataSource;
 		const Glib::ustring sql;
-		void rebindCurrentValue(const Glib::ustring & id, ODBC::Command *, unsigned int) const;
+
 	private:
 		mutable ODBC::SelectCommand * query;
 };
diff --git a/project2/sqlTask.cpp b/project2/sqlTask.cpp
index e6fec24..3811b43 100644
--- a/project2/sqlTask.cpp
+++ b/project2/sqlTask.cpp
@@ -24,21 +24,7 @@ _SqlTask::execute(const ApplicationEngine * ep, const PerRowValues * parent) con
 {
 	ODBC::ModifyCommand modify(ep->dataSource<_RdbmsDataSource>(dataSource)->getWritable(), sql);
 	BOOST_FOREACH(Parameters::value_type p, parameters) {
-		if (p.second->source == "uri") {
-			modify.bindParamS(p.second->bind, ep->env()->getParamUri(p.second->id));
-		}
-		else if (p.second->source == "query") {
-			modify.bindParamS(p.second->bind, ep->env()->getParamQuery(p.second->id));
-		}
-		else if (parent && p.second->source == "parent") {
-			const _SqlView * psqlview = dynamic_cast<const _SqlView *>(parent);
-			if (psqlview) {
-				psqlview->rebindCurrentValue(p.second->id, &modify, p.second->bind);
-			}
-			else {
-				modify.bindParamS(p.second->bind, parent->getCurrentValue(p.second->id));
-			}
-		}
+		modify.bindParamS(p.second->bind, p.second->value);
 	}
 	modify.execute();
 }
diff --git a/project2/sqlView.cpp b/project2/sqlView.cpp
index cab4ca5..41fa441 100644
--- a/project2/sqlView.cpp
+++ b/project2/sqlView.cpp
@@ -27,32 +27,12 @@ _SqlView::getCurrentValue(const Glib::ustring & id) const
 	return (*query)[id].compose();
 }
 
-void
-_SqlView::rebindCurrentValue(const Glib::ustring & id, ODBC::Command * cmd, unsigned int bind) const
-{
-	(*query)[id].rebind(cmd, bind);
-}
-
 void _SqlView::execute(xmlpp::Element * par, const ApplicationEngine * ep, const _View * parent) const
 {
 	typedef std::map<std::string, xmlpp::Element *> Columns;
 	query = new ODBC::SelectCommand(ep->dataSource<_RdbmsDataSource>(dataSource)->getReadonly(), sql);
 	BOOST_FOREACH(Parameters::value_type p, parameters) {
-		if (p.second->source == "uri") {
-			query->bindParamS(p.second->bind, ep->env()->getParamUri(p.second->id));
-		}
-		else if (p.second->source == "query") {
-			query->bindParamS(p.second->bind, ep->env()->getParamQuery(p.second->id));
-		}
-		else if (parent && p.second->source == "parent") {
-			const _SqlView * psqlview = dynamic_cast<const _SqlView *>(parent);
-			if (psqlview) {
-				psqlview->rebindCurrentValue(p.second->id, query, p.second->bind);
-			}
-			else {
-				query->bindParamS(p.second->bind, parent->getCurrentValue(p.second->id));
-			}
-		}
+		query->bindParamS(p.second->bind, p.second->value);
 	}
 	xmlpp::Element * set = par->add_child(name);
 	while (query->fetch()) {
diff --git a/project2/sqlView.h b/project2/sqlView.h
index 1a77e7d..5fd8a48 100644
--- a/project2/sqlView.h
+++ b/project2/sqlView.h
@@ -18,7 +18,7 @@ class _SqlView : public IHaveParameters, public _View {
 		Glib::ustring getCurrentValue(const Glib::ustring & id) const;
 		const std::string dataSource;
 		const Glib::ustring sql;
-		void rebindCurrentValue(const Glib::ustring & id, ODBC::Command *, unsigned int) const;
+
 	private:
 		mutable ODBC::SelectCommand * query;
 };
diff --git a/project2/variables.cpp b/project2/variables.cpp
new file mode 100644
index 0000000..f8fe4bb
--- /dev/null
+++ b/project2/variables.cpp
@@ -0,0 +1,148 @@
+#include "variables.h"
+#include "appEngine.h"
+#include "perRowValues.h"
+#include "session.h"
+#include <libxml++/nodes/textnode.h>
+#include <stdexcept>
+#include <boost/tokenizer.hpp>
+#include <boost/foreach.hpp>
+
+class VariableLiteral : public VariableImpl {
+	public:
+		VariableLiteral(const Glib::ustring & src) : VariableImpl(src) { }
+
+		virtual const Glib::ustring & value() const { return source; }
+};
+
+class VariableImplDyn : public VariableImpl {
+	public:
+		VariableImplDyn(const Glib::ustring & src) : VariableImpl(src), cacheValid(false) { }
+		virtual const Glib::ustring & value() const = 0;
+
+	protected:
+		mutable Glib::ustring cache;
+		mutable bool cacheValid;
+};
+
+class VariableSession : public VariableImplDyn {
+	public:
+		VariableSession(const Glib::ustring & src) : VariableImplDyn(src) { }
+		const Glib::ustring & value() const
+		{
+			if (!cacheValid) {
+				cache = ApplicationEngine::getCurrent()->session()->GetValue(source.substr(1));
+				cacheValid = true;
+			}
+			return cache;
+		}
+};
+
+class VariableParam : public VariableImplDyn {
+	public:
+		VariableParam(const Glib::ustring & src) : VariableImplDyn(src) { }
+		const Glib::ustring & value() const
+		{
+			if (!cacheValid) {
+				cache = ApplicationEngine::getCurrent()->env()->getParamQuery(source.substr(1));
+				cacheValid = true;
+			}
+			return cache;
+		}
+};
+
+class VariableUri : public VariableImplDyn {
+	public:
+		VariableUri(const Glib::ustring & src) : VariableImplDyn(src) { }
+		const Glib::ustring & value() const
+		{
+			if (!cacheValid) {
+				cache = ApplicationEngine::getCurrent()->env()->getParamUri(source.substr(1));
+				cacheValid = true;
+			}
+			return cache;
+		}
+};
+
+class VariableParent : public VariableImplDyn {
+	public:
+		VariableParent(const Glib::ustring & src) : VariableImplDyn(src) { }
+		const Glib::ustring & value() const
+		{
+			if (!cacheValid) {
+				PerRowValues::RowValuesStack::const_iterator r = PerRowValues::Stack().end();
+				Glib::ustring::const_iterator c = source.begin();
+				while (*c == '^') {
+					r--;
+					c++;
+				}
+				cache = (*r)->getCurrentValue(Glib::ustring(c, source.end()));
+				cacheValid = true;
+			}
+			return cache;
+		}
+};
+
+class VariableParse : public VariableImplDyn {
+	public:
+		VariableParse(const Glib::ustring & src) : VariableImplDyn(src) { }
+		const Glib::ustring & value() const
+		{
+			if (!cacheValid) {
+				boost::char_separator<char> sep(" ");
+				boost::tokenizer<boost::char_separator<char> > tokens(source.raw(), sep);
+				std::list<Variable::VariableImplPtr> vars;
+				size_t len = 0;
+				BOOST_FOREACH(std::string t, tokens) {
+					Variable::VariableImplPtr vip = Variable::create(t);
+					len += vip->value().length() + 1;
+					vars.push_back(vip);
+				}
+				cache.reserve(len);
+				BOOST_FOREACH(Variable::VariableImplPtr v, vars) {
+					if (cache.length()) {
+						cache.append(" ");
+					}
+					cache.append(v->value());
+				}
+				cacheValid = true;
+			}
+			return cache;
+		}
+};
+
+Variable::Variable(const Glib::ustring & s) :
+	var(create(s))
+{
+}
+
+Variable::Variable(xmlpp::Attribute * a) :
+	var(create(a->get_value()))
+{
+}
+
+Variable::Variable(xmlpp::Element * e) :
+	var(create(e->get_child_text()->get_content()))
+{
+}
+
+Variable::VariableImplPtr
+Variable::create(const Glib::ustring & s)
+{
+	switch (s[0]) {
+		case '$': // param
+			return VariableImplPtr(new VariableParam(s));
+		case '%': // session
+			return VariableImplPtr(new VariableSession(s));
+		case '^': // parent
+			return VariableImplPtr(new VariableParent(s));
+		case '/': // uri
+			return VariableImplPtr(new VariableUri(s));
+		case '*': // parser
+			return VariableImplPtr(new VariableParse(s));
+		case '=': // literal (explicit)
+			return VariableImplPtr(new VariableParse(s.substr(1)));
+		default:
+			return VariableImplPtr(new VariableLiteral(s));
+	}
+}
+
diff --git a/project2/variables.h b/project2/variables.h
new file mode 100644
index 0000000..cba303e
--- /dev/null
+++ b/project2/variables.h
@@ -0,0 +1,37 @@
+#ifndef VARIABLES_H
+#define VARIABLES_H
+
+#include <boost/shared_ptr.hpp>
+#include <glibmm/ustring.h>
+#include <libxml++/nodes/element.h>
+#include <libxml++/attribute.h>
+
+class VariableImpl {
+	public:
+		virtual const Glib::ustring & value() const = 0;
+
+	protected:
+		VariableImpl(const Glib::ustring & src) : source(src) { }
+		const Glib::ustring source;
+};
+
+
+class Variable {
+	public:
+		typedef boost::shared_ptr<VariableImpl> VariableImplPtr;
+
+		Variable(xmlpp::Attribute *);
+		Variable(xmlpp::Element *);
+		Variable(const Glib::ustring & s);
+
+		operator const Glib::ustring & () const { return var->value(); }
+		const Glib::ustring & operator()() const { return var->value(); }
+
+	private:
+		friend class VariableParse;
+		static VariableImplPtr create(const Glib::ustring & s);
+		VariableImplPtr var;
+};
+
+#endif
+
diff --git a/project2/view.cpp b/project2/view.cpp
index c36c43d..3a99aa6 100644
--- a/project2/view.cpp
+++ b/project2/view.cpp
@@ -24,8 +24,16 @@ _View::AddLoaders(Loaders & l, Views & views)
 void
 _View::executeChildren(xmlpp::Element * record, const ApplicationEngine * ep, const _View * parent) const
 {
-	BOOST_FOREACH(Views::value_type sq, subViews) {
-		sq.second->execute(record, ep, this);
+	try {
+		PerRowValues::beginRow(this);
+		BOOST_FOREACH(Views::value_type sq, subViews) {
+			sq.second->execute(record, ep, this);
+		}
+		PerRowValues::endRow(this);
+	}
+	catch (...) {
+		PerRowValues::endRow(this);
+		throw;
 	}
 }