Also it will be nice at some point when I have the time, to get down to writing an editor for it or extending something like Padre.

I have some ideas in mind for instance

(debug)<dump>$foo</dump>(/inc)

The syntax highlighter (and checker) would not need to know anything about what the tags actually do, all it needs to understand is the bracket schema.

Also, I had in mind the ability to run a tag in isolation so you can see what it returns, and possibly if the editor is smart enough it could add a + sign next to things like the <inc> tag so you can see the result of including the given path. I.E;

(inc)path/to/file(/inc)+

Then when you click on the + sign the sub "inc" gets run, loads the file with the given path, and displays its results inline;

(inc)
here is the file you requested
(/inc)-

You could then edit the loaded file in place, and when you click the - the editor saves both files. and returns the display to how it looked at the start. This gives the advantage that you can be sure your path statement is correct, you can create and edit a new file by typing in the path and clicking the plus sign, and you don't need to worry about saving the files or having multiple windows or tabs open with different files to switch between them.

The sub file can also contain another nested heirarchy of tags, including more statements to include, like russian dolls.

When your building a new system you open the editor and start by typing :

(use)(qd)action(/qd)(/use)+

Then you give the editor a request so that the value of action is known, click the + and start writing that action, when your done with that action you give the editor another request and start writing the next action and so on.

I will eventually get round to writing this, but I only have one pair of hands and right now I have significantly more important tasks to complete so I can get out of having to visit the jobcenter twice monthly to beg for my survival pittance.