You are thinking of the pre-processor (parser actually), which will create the graphs using the existing code.
This is nice idea too, but I had something different.
With that old IDE I could build the code from blocks, like IF,LOOP,EXECUTE,SWITCH,CALL, etc.
Every block has to be inserted into a sheet - call it a page.
When I say "inserted" - I mean literally. Something like a dialog editor.
After being inserted - the block must be connected by lines with other blocks.
It was fun, but not a solution to build large projects - too much useless work.