I got live update messages to work in DPLWB. Draw.io -> choreographer.py -> spawn transpiler -> choreographer.py -> dplwb.html. The transpiler, while working, sends little updates (JSON objects (an array of one object consisting of a pair of strings)) to the choreographer which are immediately sent to dplwb.html. Final result is sent to dplwb.html as an array of JSON objects. Turn-around is "fast enough" (seconds) to be usable in bootstrapping and debugging this stuff more deeply. [DPLWB == Diagrammatic Programming Language WorkBench]