What are the thoughts on calling GOAT (https://github.com/blampe/goat)
or ASCIITOSVG (https://github.com/dhobsd/asciitosvg) from pandoc?
I think it would make a good further enhancement to pandoc's enhanced markdown.
GOAT is the better tool, and will take ASCII diagrams and produce SVG output.
ASCIITOSVG does the same but handles more basic diagrams (but the output is prettier).
It may work similar to diagrams-pandoc (http://hackage.haskell.org/package/diagrams-pandoc)
or the mermaid filter (https://github.com/raghur/mermaid-filter)
Sam