[libgdamm] SqlExpr: Add empty().

[Murray Cumming <murrayc src gnome org>]

commit f45acb1905580433ffe46fb58606d88beb8c6aaf
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu May 6 18:10:54 2010 +0200

    SqlExpr: Add empty().
    
    * libgda/src/sqlexpr.[hg|ccg]: Added empty() so we can check if it is a
        default empty instance. This makes it more useful.

 ChangeLog              |    7 +++++++
 libgda/src/sqlexpr.ccg |    5 +++++
 libgda/src/sqlexpr.hg  |    2 ++
 3 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 9ce2406..eb994fc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2010-05-06  Murray Cumming  <murrayc murrayc com>
 
+   SqlExpr: Add empty().
+
+	* libgda/src/sqlexpr.[hg|ccg]: Added empty() so we can check if it is a
+    default empty instance. This makes it more useful.
+
+2010-05-06  Murray Cumming  <murrayc murrayc com>
+
     Added new SqlBuilder methods.
 
 	* libgda/src/libgda_methods.defs: Regenerated with h2defs.py
diff --git a/libgda/src/sqlexpr.ccg b/libgda/src/sqlexpr.ccg
index 060a7dc..1d44b21 100644
--- a/libgda/src/sqlexpr.ccg
+++ b/libgda/src/sqlexpr.ccg
@@ -33,6 +33,11 @@ SqlExpr::SqlExpr(GdaSqlAnyPart *parent)
 {
 }
 
+bool SqlExpr::empty() const
+{
+  return !gobject_;
+}
+
 } // namespace Gda
 
 } // namesoace Gnome
diff --git a/libgda/src/sqlexpr.hg b/libgda/src/sqlexpr.hg
index 550cc64..d3ab29b 100644
--- a/libgda/src/sqlexpr.hg
+++ b/libgda/src/sqlexpr.hg
@@ -41,6 +41,8 @@ public:
   explicit SqlExpr(GdaSqlAnyPart *parent);
   _IGNORE(gda_sql_expr_new)
 
+  bool empty() const;
+
   _WRAP_METHOD(Glib::ustring serialize() const, gda_sql_expr_serialize)
 
   //TODO: _WRAP_METHOD(void take_select(GdaSqlStatement *stmt), gda_sql_expr_take_select)