[REBOL] [encompass.r]
From: maximo:meteorstudios at: 26-Nov-2003 12:34
Hi all,
I just wanted to let everyone know of a nifty function I just uploaded to the rebol.r
repository, it is called emcompass.
I wanted to share it here, but its too large and will wordwrap pretty badly...
http://www.rebol.org/cgi-bin/cgiwrap/rebol/view-script.r?script=encompass.r
There are a lot of comments in the code (per my usual coding style)
It lets you add code around a function and wraps all refinements to it. It is a follow
up to the question I asked a week ago about transfering all refinements to another function
of the same/lesser template.
'ENCOMPASS can be used to modify behaviour of code, without actually tampering with the
code itself. It is especially usefull in patching native! funcs.
simply put you can:
-extend the argument list by adding new parameters or refinements,
-add pre-process code, executed before the function you are enclosing.
-add pos-tprocess code, executed after the function you are enclosing.
-the return value (if any) of the enclosed function can be created/modified in the
post-process, which is in turn returned by the encompassing function.
the example within the rebol.org encompass.r script show how you can add a confirm on
every 'read done, in the case where you want to monitor and intercept what a script is
about to read, just before it does. Canceling the read, terminates the script.
the example even adds a refinement to read /safe which prevent any confirmation when
you know the file is safe.
the patch replaces the global read statement, so calling this at the begining of your
code actually protects you from someone prying files on your disk and sending them over
the net without your knowledge.
good thing is that if the template to read changes in the future, you have nothing to
edit, it just continues using the new template, because you do not have to tamper with
it yourself.
The example itself is simple, but it shows just how easy it is to extend/restrict functionality
of any function, method, action or native.
hope some of you find it usefull, I know I really am!
ciao!
-MAx
PS: if some of you noticed it yesterday, I have severely updated it last night, its worth
getting the newer version (1.0.2)
-------------
Steel project coordinator
http://www.rebol.it/~steel
