Non-language-specific graphical code organization

Question

I'm working with a PLC program that runs over a hundred subroutines in parallel, and each one affects the flow of the others. Countless labels and GOTOs, function calls, etc. My office desk is covered with little stickynotes to help me visualize and track the flow through the program, but it's starting to get too complex to manage that way. Has anyone ever heard of any sort of graphical flowchart-ish program to help organize stuff like that? What I'm picturing is a little text box that I can fill full of pseudocode, then link to other textboxes. Unless I'm actually working in them, the boxes stay collapsed, and you only see a title or something to show what it is. All the links connected to my "open" box are red, or bold, and all other links are dim gray, or maybe not even shown.
Does anything like this exist? I've heard that MATLAB uses something similar to what I'm picturing, but what I want is just a generic sort of "fill in your own info" program; not language-specific. I'd be tempted to make one on my own, but I'm way too busy with WORK-work to start creating NOT-AT-WORK-work for myself.

Answer 1

You can try Dia or yEd. Both are available for linux, I know that yEd is also for Windows. Those are diagramming tools, maybe you'll find them useful.

Answer 2

Graphviz http://graphviz.org/ would be a good tool to achieve this. It allows you to write your graph descriptions as simple text and it generates and lays out the graph. It can handle pretty large and complicated flows. Here is a simple example to give you an idea of the syntax:

digraph g {
    NodeA -> NodeB;
}