Pointers for these pointers...?

[DirtyClamDigger]

Hi Everyone: I'm trying to develop a property list to include as
metadata about my object classes. i.e. I want each class I'm developing
to include a PropertyList which will contain ObjectProperty pointers.
ObjectProperty is a class containing the typeid.name() of a type as
it's ObjectType as well as an ObjectName and ObjectDescription.
Basically 3 strings of metadata describing each of a class' member
variables (and hopefully functions) so that the class can report to a
query from another class what properties it has available for access at
run time.

Here is what I have and the error I'm getting:

// ObjectProperty.hpp
#pragma once
#include <string>
#include <list>
#include <typeinfo>


namespace Properties
{
template<typename aProperty> class ObjectProperty
{
private:
std::string PropertyName;
std::string PropertyType;
std::string PropertyDescription;

public:
ObjectProperty(
const std::string& _PropertyName,
const std::string& _PropertyType,
const std::string& _PropertyDescription ):
PropertyName(_PropertyName),
PropertyType(_PropertyType),
PropertyDescription(_PropertyDescription){}

ObjectProperty(
const std::string& _PropertyName,
const std::string& _PropertyDescription ):
PropertyName(_PropertyName),
PropertyType(typeid(aProperty).name()),
PropertyDescription(_PropertyDescription){}

ObjectProperty():
PropertyName(),
PropertyType(typeid(aProperty).name()),
PropertyDescription(){}

~ObjectProperty(){}

const std::string& getPropertyName() const
{
return PropertyName;
}

const std::string& getPropertyType() const
{
return PropertyType;
}

const std::string& getPropertyDescription() const
{
return PropertyDescription;
}

void setPropertyName( const std::string& _PropertyName )
{
PropertyName = _PropertyName;
}

void setPropertyType( const std::string& _PropertyType )
{
PropertyType = _PropertyType;
}

void setPropertyDescription( const std::string& _PropertyDescription
)
{
PropertyDescription = _PropertyDescription;
}
};

// a simple wrapper to have further functionality added
class PropertyList
{
public:
// will be made private later after I get it working )
std::list<ObjectProperty*> theProperties;

// public functions such as....
// void displayProperties();
// const list<ObjectProperty*>& getProperties();
// bool compareProperties(PropertyList&, PropertyList&);
// ....
};

};

// ObjectPropertyDriver.cpp
#include <iostream>
#include "ObjectProperty.hpp"

using namespace Properties;
using namespace std;

int main(void)
{
try
{
// active code

PropertyList pl;
ObjectProperty< char* >* op = new ObjectProperty< char* >("My char*
Property", "My char* Property Description");
pl.theProperties.push_back(op);

return 0;
}
catch(...) // any old exception not already caught
{
cerr << "OOooops ... unexpected exception\n";
}

}

Error 1 error C2664: 'std::list<_Ty>:ush_back' : cannot convert
parameter 1 from 'Properties::ObjectProperty<aProperty> *' to
'Properties::ObjectProperty *const &' ...\objectpropertydriver.cpp 15

compiler is devstudio 8.blah....

If I'm going about it completely wrong then a pointer in the right
direction would be helpful, otherwise any suggestions at all are
welcome....

TIA,
LJH.

 

[Artie Gold]

Hi Everyone: I'm trying to develop a property list to include as
metadata about my object classes. i.e. I want each class I'm developing
to include a PropertyList which will contain ObjectProperty pointers.
ObjectProperty is a class containing the typeid.name() of a type as
it's ObjectType as well as an ObjectName and ObjectDescription.
Basically 3 strings of metadata describing each of a class' member
variables (and hopefully functions) so that the class can report to a
query from another class what properties it has available for access at
run time.

Here is what I have and the error I'm getting:

I'm not entirely clear on what you're doing (and I haven't spent
sufficient time looking) but I this might help. See below:

// ObjectProperty.hpp
#pragma once
#include <string>
#include <list>
#include <typeinfo>


namespace Properties
{
template<typename aProperty> class ObjectProperty
{
private:
std::string PropertyName;
std::string PropertyType;
std::string PropertyDescription;

public:
ObjectProperty(
const std::string& _PropertyName,
const std::string& _PropertyType,
const std::string& _PropertyDescription ):
PropertyName(_PropertyName),
PropertyType(_PropertyType),
PropertyDescription(_PropertyDescription){}

ObjectProperty(
const std::string& _PropertyName,
const std::string& _PropertyDescription ):
PropertyName(_PropertyName),
PropertyType(typeid(aProperty).name()),
PropertyDescription(_PropertyDescription){}

ObjectProperty():
PropertyName(),
PropertyType(typeid(aProperty).name()),
PropertyDescription(){}

~ObjectProperty(){}

const std::string& getPropertyName() const
{
return PropertyName;
}

const std::string& getPropertyType() const
{
return PropertyType;
}

const std::string& getPropertyDescription() const
{
return PropertyDescription;
}

void setPropertyName( const std::string& _PropertyName )
{
PropertyName = _PropertyName;
}

void setPropertyType( const std::string& _PropertyType )
{
PropertyType = _PropertyType;
}

void setPropertyDescription( const std::string& _PropertyDescription
)
{
PropertyDescription = _PropertyDescription;
}
};

// a simple wrapper to have further functionality added
class PropertyList
{
public:
// will be made private later after I get it working )
std::list<ObjectProperty*> theProperties;

// ITYM:
std::list<ObjectProperty<aProperty>*> theProperties;

// as ObjectProperty is a templated class

// public functions such as....
// void displayProperties();
// const list<ObjectProperty*>& getProperties();
// bool compareProperties(PropertyList&, PropertyList&);
// ....
};

};

// ObjectPropertyDriver.cpp
#include <iostream>
#include "ObjectProperty.hpp"

using namespace Properties;
using namespace std;

int main(void)
{
try
{
// active code

PropertyList pl;
ObjectProperty< char* >* op = new ObjectProperty< char* >("My char*
Property", "My char* Property Description");
pl.theProperties.push_back(op);

return 0;
}
catch(...) // any old exception not already caught
{
cerr << "OOooops ... unexpected exception\n";
}

}

Error 1 error C2664: 'std::list<_Ty>:ush_back' : cannot convert
parameter 1 from 'Properties::ObjectProperty<aProperty> *' to
'Properties::ObjectProperty *const &' ...\objectpropertydriver.cpp 15

compiler is devstudio 8.blah....

If I'm going about it completely wrong then a pointer in the right
direction would be helpful, otherwise any suggestions at all are
welcome....

See above.

HTH,
--ag

 

[DirtyClamDigger]

Thanks, Artie, but that doesn't seem to work either. What is bugging me
is that if I comment out the push_back call in the code above then it
compiles and runs fine. I'm simply trying to find a way to have a
property list associated with each class I create so that I can query
objects of that class as to the descriptions of their data. i.e. data
about the data is called 'meta'data. In my mind that means having a
static list of name/type/description triplets describing the
datamembers of a class..

e.g. // this code is just off the top of my head to demo my
intent...don't expect correctness! )

class aClass{
public:

int anInt;
double aDouble;
static PropertyList dataProperties;

//...class def'ns etc...
void loadProperites(){
ObjectProperty*<double> op = new ObjectProperty<double>("aDouble", "A
Double defined for this dummy class);
dataProperties.push_back(*op);
}
};...//end class

Anyway, I tried your suggestion and it still fetches up with a type
mismatch error. I guess I'm going to have to sit and think on it a bit
more....

Thanks anyway.

regards,
LJH