New keywords

[hari4063]

This is mostly for Borland Builder and new keyword "__property ". I try (this is not my original idea) to make class (template) that imitates __property. Basic idea was proposed by my friend, but I try to rewrite Borlands VCL without __property to ensure that only standard C++ is used.

Is any work similary to this one.


Greetz.

[AirPete]

Re: New keywords

hari4063 wrote:[color=blue]
> This is mostly for Borland Builder and new keyword "__property ". I
> try (this is not my original idea) to make class (template) that
> imitates __property. Basic idea was proposed by my friend, but I try
> to rewrite Borlands VCL without __property to ensure that only
> standard C++ is used.
>
> Is any work similary to this one.
>
>
> Greetz.[/color]

Is something like this what you want (I don't know what borland's extensions
do)?

- Pete


#include <iostream>
#include <string>
using namespace std;
template <class T, class Modify>
class property
{
protected:
T var;
Modify mod;
public:
property<T, Modify>(const T& init, const Modify& m)
: mod(m), var(init)
{}
operator T()
{
return var;
}
property& operator =(const T& val)
{
if(!mod(val))
throw invalid_argumen t("bad property argument.");
var = val;
return *this;
}
};
template<class T>
struct RangeValidation PropModified
{
string msg;
T minval, maxval;
public:
RangeValidation PropModified<T> (string m, const T& minv, const T& maxv)
: msg(m),
minval(minv),
maxval(maxv)
{}
bool operator() (const T& val)
{
if(val >= minval && val <= maxval)
{
cout << msg;
return true;
}
else
return false;
}
};
int main(int argc, char* argv[])
{
property<int, RangeValidation PropModified<in t> >
p(0, RangeValidation PropModified<in t>("the property is being modifed!\n", 0,
100));
cout << p << endl;
p = 5;
cout << p << endl;
p = 10;
cout << p << endl;
try
{
p = -1;
cout << p << endl;
p = 1000;
cout << p << endl;
}
catch(invalid_a rgument ex)
{
cout << ex.what() << endl;
}
return 0;
}