My first post to this list...
I am a SuperCard user (for 14 years). I am of course interested in Revolution's multi-platform output. However... in reading some of your tutorials, I came across a blurb outlining a restriction on making run-time changes to Revolution projects (stacks). I am interested in evolving code... projects that react to, optimize and adjust to their environment... who uses them and their intent, and available media, data and communications streams. How does one do this with Revolution?
Hello Randall -
Good to see you here.
As Bill pointed out, Rev standalones can't modify themselves because no OS allows an executable file to modify itself at runtime except Mac Classic, where Rev enforces the same rule for consistency.
However, it's easy enough to simply move code into stack files that are external to the application. Such components can easily modify themselves just as SC projects can.
But there are other options that may be worth considering. Maureen Caudill has written some good books and articles on neural networks and genetic algorithms, and both are largely based on changes to data rather than code per se. While the algorithms she discusses in her articles in AI magazine and elsewhere are largely language-specific, many of the underlying principles can be well emulated using constructs available in Rev.
Perhaps chief among these are the getProp and setProp tokens. These are very powerful tools to manage custom properties in complex ways by trapping the setting or getting of a property to invoke any number of actions. This allows tremendous flexibility with very natural syntax.
For example, you could say:
set the mediaPath of this stack to tMyPath
...and have this definition in the stack script (or a backscript or a library or anywhere else in the message path):
setProp mediaPath pPath put pPath into fld "mediaPath" set the filename of player 1 to pPath set the hilite of btn "Loaded" to true start player 1 end mediaPath
That's a very simple example but illustrates the power of setProp for invoking multiple actions from a single property setting.
Another construct worth noting is that custom properties can be stored in any number of custom property sets, and can be addressed with array notation using either strings, numbers, or variables:
put 2 into tMyVar get the userInfo[tMyVar] of stack "Prefs"
By having multiple property sets you could construct (among other things) parallel sets of properties whose values get invoked under different circumstances for obtaining different data.
For example, if you had three properties for each user, you could assign a different customPropertySet for each user with the same property names in each:
set the customPropertySet of stack "UserInfo" to "Joe" put the userName of stack "UserInfo" into tJoesName put the userPassword of stack "UserInfo" into tJoesPassword put the userLocation of stack "UserInfo" into tJoesLocation -- set the customPropertySet of stack "UserInfo" to "Steve" put the userName of stack "UserInfo" into tStevesName put the userPassword of stack "UserInfo" into tStevesPassword put the userLocation of stack "UserInfo" into tStevesLocation
For more ideas on using custom properties and property sets for hierarchical data storage, see:
<http://lists.runrev.com/pipermail/use-revolution/2002-July/006149.html>
There is much to learn in using Rev, but coming from a strong SC background as you are you'll find most of the syntax and algorithms you're familiar with can be implemented in Rev with little or no modification. But as you learn more about Rev you'll find many new options like those outlined above which may open new doors for you.
But whether adapting an SC script for use in Rev or learning new techniques, this list is definitely the place to be.
Welcome aboard.
-- Richard Gaskin Fourth World Media Corporation ___________________________________________________ Rev tools and more: http://www.fourthworld.com/rev _______________________________________________ use-revolution mailing list [EMAIL PROTECTED] http://lists.runrev.com/mailman/listinfo/use-revolution
