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.

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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

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