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Home » U++ Library support » U++ Core » Value: BOOLEAN_V, USERVALUE_V [REQUEST]
Re: Value: BOOLEAN_V, USERVALUE_V [REQUEST] [message #7126 is a reply to message #7119] Fri, 15 December 2006 09:41 Go to previous messageGo to previous message
fallingdutch is currently offline  fallingdutch
Messages: 258
Registered: July 2006
Experienced Member
luzr wrote on Thu, 14 December 2006 20:28

I am not quite sure BOOL_V is a good idea, but be it...

Why isn't it a good idea in your oppinon?
it is needed in database, too

luzr wrote on Thu, 14 December 2006 20:28


But IMHO be aware that such solution is extremely fragile because of conversions between numerical values (note that IsNumber is the recommended method of type inquiry there).

What about just adding a new ID BOOL_V and a function IsBool that returns true if the Value was constructed with a bool as param.
all other conversions will stay the same, so bool is returned as integer, means IsNumber tests on BOOL_V, too and BOOL_V is casted to int every time. so the whole is not broken, but one can distinguish, wether the value was created with a boolean or with any other number.
That would result in:
//Value.h
const int BOOLEAN_V = [booleanid];
inline dword ValueTypeNo(const bool) {return BOOLEAN_V;}
inline bool IsNumber(const Value& v)   { return v.GetType() == DOUBLE_V || v.GetType() == INT_V || \
v.GetType() == BOOL_V  || v.GetType() == INT64_V; }

//Value.cpp
Value::Value(bool b) { ptr = new RichValueRep<bool>(b);}
Value::operator int() const //same for int64, double
{
	if(IsNull()) return Null;
	return GetType() == INT_V   ? RichValue<int>::Extract(*this)
	: GetType() == INT64_V ? int(RichValue<int64>::Extract(*this))
	: GetType() == BOOL_V ? int(RichValue<bool>::Extract(*this)) 
	: int(RichValue<double>::Extract(*this));
}

luzr wrote on Thu, 14 December 2006 20:28


Maybe the right solution is to provide special type, RpcBool, or something like that.

That would mean i have to create a RpcValue:Value with just the changes mentioned above.
luzr wrote on Thu, 14 December 2006 20:28


USERVALUE_V does not have sense. I must admit that the idea of numeric ids is somewhat fragile as well, but USERVALUE_V would not solve that. At least Value system checks for duplicate definitions.

Why not? so anyone using u++ and wants to define his own id knows where to start: USERVALUE_V+k (k in {0,1,2, ...} is known to be unused.

Bas
 
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