To Rev or not to Rev

[Rob Cozens]

Frank, et al:

>As for an object-oriented programming language, no Rev is *not* an 
>object-oriented programming language, at least not in the traditional sense.
>
>
>For example, in Rev, let's  say we want to change the label of the button; 
>we do this with a command like:
>
>set the label of button "My Button" to "Hello"
>
>
>In other words, we are giving an instruction to Rev, such that our script 
>code changes the button's label.  In more traditional OOP, we instead send 
>a message to the button, asking it to change its own label; something more 
>like (pseudo-code, not necessarily in any "real" programming language):
>
>tell button "My Button" to set its label to "Hello"
>
>
>At first the distinction may seem quite subtle, and you may not recognize 
>the benefits to this, but consider that I want to create a new type of 
>button with certain characteristics, one of which is that the label of the 
>button always begin with a digit.  I can enforce this by having the button 
>reject an attempt to set its label to anything other than a string 
>starting with a digit (again with the pseudo-code):
>
>when asked to set my label to x
>   if char 1 of x is a number then
>     set the label of me to x
>   else
>     throw "Invalid Label"
>   end if
>end when asked to set my label
>
>
>Note that the prior code would still work the same way, and would not need 
>to know what kind of button it was dealing with (of course, it would have 
>an exception raised with this kind of button, since "Hello" does not start 
>with a digit...)
>
>We can't currently do this with Rev.

In button script:

on setMyLabel labelName
   if char 1 of labelName is a number then
       set the label of me to labelName
       return empty
   end if
   return "Invalid label name:"&&labelName
end setMyLabel

elsewhere:

send "setMyLabel Hello" to button id targetButtonId

??

Rob Cozens CCW
Serendipity Software Company

"And I, which was two fooles, do so grow three;
  Who are a little wise, the best fooles bee."

  from "The Triple Foole" by John Donne (1572-1631)