but then you'd be open to the weird situation of having an object that claims it is null but contains a value. If you need a null object, just create a new one and don't initialize it.
/t >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] On Behalf Of Bill Rawlinson >Sent: Wednesday, September 21, 2005 4:00 PM >To: [email protected] >Subject: Re: [CFCDev] Default for Dates in a Transfer object > >or, if you did want to null the object you could have a method, >setNull() which just turns the flag back on. > ><cfset myString = createobject("component","types.String")> > ><cfoutput>#myString.isNull()#</cfoutput> <--- should return "true" ---> > ><cfset myString.init("Hello World")> > ><cfoutput>#myString.isNull()#</cfoutput> <--- should return >"false" ---> > >.... > ><cfset myString.setNull() /> > ><cfoutput>#myString.isNull()#</cfoutput> <!--- should return >"true" ---> > > >I don't know if this would be necessary or not but at least it would >give you the flexibility to make sure it is null at some later point. > > >On 9/21/05, RADEMAKERS Tanguy <[EMAIL PROTECTED]> wrote: >> i'd go with "objects are null until explicitly initialized" >- you could >> track it with a private attribute and then toggle that from >within the >> init method. You don't ever need to "nullify" an object once >it has been >> initialized... >> >> /t >> >> >-----Original Message----- >> >From: [EMAIL PROTECTED] >> >[mailto:[EMAIL PROTECTED] On Behalf Of Bill Rawlinson >> >Sent: Wednesday, September 21, 2005 3:32 PM >> >To: [email protected] >> >Subject: Re: [CFCDev] Default for Dates in a Transfer object >> > >> >Kerry, >> >You would define you're own rule for what a NULL is for that type >> >since you're creating the component. >> > >> >If a zero-length string is a null to you thens ure isNull >would return >> >true. if the rule was the string had to be equal to "NULL" >then no, a >> >zero length string would return false. >> > >> > >> >Bill >> > >> > >> >On 9/21/05, Kerry <[EMAIL PROTECTED]> wrote: >> >> >basically an isNull() method >> >> hmm, would that return true simply if the value had zero length? >> >> or only if it had never been set? >> >> >> >> >> >> -----Original Message----- >> >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] >> >> Behalf Of RADEMAKERS Tanguy >> >> Sent: 21 September 2005 13:11 >> >> To: [email protected] >> >> Subject: RE: [CFCDev] Default for Dates in a Transfer object >> >> >> >> >> >> >Another option is to roll your own date object and pass an >> >instance of >> >> >it into the function instead. >> >> >> >> Actually, this could be one way around the whole type >safety / null >> >> problem with cf - develop a system of object types (Date.cfc, >> >> Integer.cfc, String.cfc, etc). Then you could choose to work with >> >> "primitives" (the regular built in cf data types) which are >> >loosely and >> >> dynamically typed and have no concept of null, or with >object types >> >> which are statically, strongly typed and do (well... can) >> >have a concept >> >> of null (basically an isNull() method). >> >> >> >> The two biggest problems i can see with this approach is >> >that a) object >> >> types would be more cumbersome to work with, since you >would have to >> >> call methods to do what you do with operators on primitives (ie no >> >> MyString = "hello world" when MyString is an object type, >> >and certainly >> >> no MyArray[1] = "value") and b) performance - creating >> >instances being >> >> expensive. >> >> >> >> On the other hand, i'd think it would be extremely >unlikely that the >> >> built-in cf data types will support the notion of null >values anytime >> >> soon, since that would break a lot of existing code. >> >> >> >> /t >> >> >> >> >> >> ---------------------------------------------------------- >> >> You are subscribed to cfcdev. 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