Choosing an External Editor
Though the Virtual Wiring System has its own built in editor, you may want an additional editor for building larger systems. Typically, larger systems require creating a number of Scripts, a kind of text file, that automate building a system. If you start creating a number of these files, you may want to use an external editor (which might support fast access to file directories, editing multiple files in parallel, syntax highlighting ....). You will want the editor running on your host system, as that is where Script files live.
Some popular text editors are vi, VIM (a fancy vi), TextMate, Sublime Text, and emacs. There's a simple editor, which is often pre-installed on many systems, called nano. All these editors are free. There are also many text editors available for purchase. Generally speaking, an editor designed for any kind of computer programming is a text editor. Editors designed for documentation (often called word processors) are not.
The important thing is that your editor is a text editor and not a word processor. The editor's output needs to be just characters with no additional attributes (bold, underscore, etc.). If you aren't sure whether your editor is outputting pure text or not, try editing a small test file and saving it. Then run
Did your editor pass the "cat" test, but you are getting weird syntax errors from the system? The "cat" test may not be enough. Some editors write "text" files, but with additional non-standard characters.
Are you using YAML to define your state machine tables, and you are getting odd syntax errors? Make sure your editor is not creating tab characters (you can use the tab key, but your editor should be tabbing with space characters). Some editors have a "soft tabs" mode to make them output spaces instead of tabs. Make sure your editor is not outputting tabs. YAML does not allow tabs.
If you are getting strange syntax errors when you try to run your Scripts, try using "cat" or your editor to look at the double quote (") characters in your Scripts. Are they the same symbol for both the left and right quote, or do they look like little paired commas, with the left quote commas upside down and the right quote commas right side up? If they look different, your editor isn't behaving the way a text editor should (it's probably a word processing editor trying to act like a text editor). You need to tweak your editor's settings or find a new editor. The free editors listed above all work well.