[REBOL] Re: object/property1: "new value"
From: dockimbel:free at: 30-Jan-2001 16:21
> I want to get a "fire" -event if an attribute, such as 'balance, is
> changed. So I can test of a valid data-type or to test wether the new value
> is in a valid range.
Define a 'set-balance (or 'let-balance) function in the account context, where
you can put all your processing code. For example :
account: make object! [
set-balance: func [value][
...process value and assign 'balance to value if ok...
So, when you want to modify 'balance somewhere in your script do :
In VisualBasic, it's the same thing except that VB will automatically call the
Let property when it encounters a "=" symbol.
If you don't like this solution, you can try another way by using the 'query
function. For example,
will return you a block of modified words in 'account (else 'none). With this
function, you can know what words have been modified in an object context and
then do the appropriate actions.