Expressions: Integrate into the property editor

- basic infrastructure for handling of expressions
- port the unit properties editor to support expressions
- port placement editor to support expressions
- expressions for double spinbox
- expressions in sketch constraints

src/App/PropertyExpressionEngine.cpp

@@ -122,8 +122,10 @@ void PropertyExpressionEngine::Paste(const Property &from)
     aboutToSetValue();
     expressions.clear();
 
-    for (ExpressionMap::const_iterator it = fromee->expressions.begin(); it != fromee->expressions.end(); ++it)
+    for (ExpressionMap::const_iterator it = fromee->expressions.begin(); it != fromee->expressions.end(); ++it) {
         expressions[it->first] = ExpressionInfo(it->second);
+        expressionChanged(it->first);
+    }
 
     validator = fromee->validator;
 
@@ -272,8 +274,10 @@ void PropertyExpressionEngine::slotObjectRenamed(const DocumentObject &obj)
 
     aboutToSetValue();
 
-    for (ExpressionMap::iterator it = expressions.begin(); it != expressions.end(); ++it)
+    for (ExpressionMap::iterator it = expressions.begin(); it != expressions.end(); ++it) {
         it->second.expression->visit(v);
+        expressionChanged(it->first);
+    }
 
     hasSetValue();
 }
@@ -312,6 +316,10 @@ void PropertyExpressionEngine::setValue(const ObjectIdentifier & path, boost::sh
     // Try to access value; it should trigger an exception if it is not supported, or if the path is invalid
     prop->getPathValue(usePath);
 
+    // Check if the current expression equals the new one and do nothing if so to reduce unneeded computations
+    if(expressions.find(usePath) != expressions.end() && expr == expressions[usePath].expression)
+        return;
+    
     if (expr) {
         std::string error = validateExpression(usePath, expr);
 
@@ -320,11 +328,13 @@ void PropertyExpressionEngine::setValue(const ObjectIdentifier & path, boost::sh
 
         aboutToSetValue();
         expressions[usePath] = ExpressionInfo(expr, comment);
+        expressionChanged(usePath);
         hasSetValue();
     }
     else {
         aboutToSetValue();
         expressions.erase(usePath);
+        expressionChanged(usePath);
         hasSetValue();
     }
 }
@@ -669,6 +679,9 @@ void PropertyExpressionEngine::renameExpressions(const std::map<ObjectIdentifier
 
     aboutToSetValue();
     expressions = newExpressions;
+    for (ExpressionMap::const_iterator i = expressions.begin(); i != expressions.end(); ++i) 
+        expressionChanged(i->first);
+    
     hasSetValue();
 }
 

src/App/PropertyExpressionEngine.h

@@ -25,6 +25,7 @@
 
 #include <boost/unordered/unordered_map.hpp>
 #include <boost/function.hpp>
+#include <boost/signals.hpp>
 #include <boost/graph/adjacency_list.hpp>
 #include <boost/graph/topological_sort.hpp>
 #include <App/Property.h>
@@ -49,7 +50,7 @@ class AppExport PropertyExpressionEngine : public App::Property
 public:
 
     typedef boost::function<std::string (const App::ObjectIdentifier & path, boost::shared_ptr<const App::Expression> expr)> ValidatorFunc;
-
+    
     /**
      * @brief The ExpressionInfo struct encapsulates an expression and a comment.
      */
@@ -117,6 +118,9 @@ public:
     size_t numExpressions() const;
 
     void slotObjectRenamed(const App::DocumentObject & obj);
+    
+    ///signal called when a expression was changed 
+    boost::signal<void (const App::ObjectIdentifier &)> expressionChanged; 
 
     /* Python interface */
     PyObject *getPyObject(void);