From fb985d981bf3126545903a2e11df3a026bae8d53 Mon Sep 17 00:00:00 2001
From: randomdan <randomdan@localhost>
Date: Sun, 18 Mar 2012 17:04:26 +0000
Subject: Centralise variable null checking

---
 project2/common/rowSet.cpp    | 6 +++---
 project2/common/variables.cpp | 6 ++++++
 project2/common/variables.h   | 1 +
 project2/xml/xmlPresenter.cpp | 2 +-
 project2/xml/xpathRows.cpp    | 2 +-
 5 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/project2/common/rowSet.cpp b/project2/common/rowSet.cpp
index cc397d1..0378b51 100644
--- a/project2/common/rowSet.cpp
+++ b/project2/common/rowSet.cpp
@@ -75,10 +75,10 @@ RowState::getCurrentValue(const Glib::ustring & col) const
 	const Columns & columns = getColumns();
 	Columns::index<byColName>::type::iterator di = columns.get<byColName>().find(col);
 	if (di != columns.get<byColName>().end()) {
-		if (!boost::get<Null>(&fields[(*di)->idx])) {
-			return fields[(*di)->idx];
+		if (fields[(*di)->idx].isNull()) {
+			return (*di)->defValue;
 		}
-		return (*di)->defValue;
+		return fields[(*di)->idx];
 	}
 	throw RowSet::FieldDoesNotExist(col);
 }
diff --git a/project2/common/variables.cpp b/project2/common/variables.cpp
index de0690b..7455e2c 100644
--- a/project2/common/variables.cpp
+++ b/project2/common/variables.cpp
@@ -200,6 +200,12 @@ VariableType::operator<(const VariableType & b) const
 	return false;
 }
 
+bool
+VariableType::isNull() const
+{
+	return (get<Null>());
+}
+
 VariableImplDyn::VariableImplDyn(ScriptNodePtr e)
 {
 	if (e) {
diff --git a/project2/common/variables.h b/project2/common/variables.h
index 2757ade..ca2cdc7 100644
--- a/project2/common/variables.h
+++ b/project2/common/variables.h
@@ -88,6 +88,7 @@ class VariableType : public _VT {
 		operator double() const;
 		operator const boost::posix_time::ptime &() const;
 		operator bool() const;
+		bool isNull() const;
 		template <typename T> T as() const { return *this; }
 		template <typename T> const T * get() const { return boost::get<T>(this); }
 
diff --git a/project2/xml/xmlPresenter.cpp b/project2/xml/xmlPresenter.cpp
index 37239fa..2650186 100644
--- a/project2/xml/xmlPresenter.cpp
+++ b/project2/xml/xmlPresenter.cpp
@@ -140,7 +140,7 @@ XmlPresenter::pushSub(const Glib::ustring & name, const Glib::ustring & ns) cons
 void
 XmlPresenter::addAttribute(const Glib::ustring & name, const Glib::ustring & ns, const VariableType & value) const
 {
-	if (!value.get<Null>()) {
+	if (!value.isNull()) {
 		nodeStack.back()->set_attribute(name, value, ns);
 	}
 }
diff --git a/project2/xml/xpathRows.cpp b/project2/xml/xpathRows.cpp
index c4fde3b..2d8ea8a 100644
--- a/project2/xml/xpathRows.cpp
+++ b/project2/xml/xpathRows.cpp
@@ -82,7 +82,7 @@ XPathRows::execute(const Glib::ustring & filter, const RowProcessor * rp) const
 		BOOST_FOREACH(const Columns::value_type & _xp, fv->columns.get<byColIdx>()) {
 			const FilterViewColumn * xp = static_cast<const FilterViewColumn *>(_xp.get());
 			const VariableType & path(xp->path);
-			if (boost::get<Null>(&path)) {
+			if (path.isNull()) {
 				continue;
 			}
 			xmlXPathObjectSPtr xpathObjI = xmlXPathObjectSPtr(xmlXPathEvalExpression(path, xpathCtx.get()), xmlXPathFreeObject);
-- 
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