[George Peter Staplin] 2006-07-28: '''TFP''' is my new programming system.  I've created what I call '''box programming'''.  Basically each box is an asynchronous process that communicates with other boxes via ports.  In TFP each box forks from the router, and does a unique job.  TFP is a domain-specific language built on top of Tcl.

[lexfiend] 2006-08-12: Which begs the question: Is '''TFP''' short for '''Tcl [Flow-based Programming]'''?

[George Peter Staplin] 2006-08-12: Yes.  I wrote a paper for the conference about this, and I give credit to [Flow-Based Programming] for inspiring what I created.  It will appear after the conference.  What's unique is my box abstraction and the domain-specific language I've created for it in Tcl.  I also used processes rather than threads, unlike some other modern implementations of FBP.  I've also changed the names of some components, because I think "router" is a better description than "scheduler" for my implementation.

The first application built with TFP is called [TFP Shell].  It's an interactive shell with image support.

----

For instance here is an image box:

======
box image {
    load [file join $::shellbinpath pngext2.so] Pngext2
} takes filename {
    if {[catch {out 1 [pngext2:decode file $filename]} result]} {
                out 0 error
                out 1 $result
                return
        }
         out 0 image
} out 2
======

To use that box I might have something like:

======
box interactor {
    #
    # This is the init path.  It can contain procs and other startup code.
    #
    package require Tk
    load [file join $::shellbinpath megaimagetk.so]
    pack [button .b -text {Load image} -command {
        out 0 /path/to/somefile.png}]
    pack [label .img]
} takes {type data} {
    switch -- $type {
        error {
            tk_messageBox -icon error -message $data
        }

        image {
            set img [image create photo]
            megaimage.to.photo $data $img
            .img configure -image $img
        }
    }
} out 1
======

Then I connect the boxes like so:

======
connect interactor 0 image 0
connect image 0 interactor 0
connect image 1 interactor 1
router
vwait forever
======


<<categories>> flow-based programming