parallel message flows

[henryscala]

Great project.

I'd like to have the parallel message flows, in some way.

For the following example: A->B:hello B->A:hello_ack C->D:hello D->C:hello_ack

The communications between C and D do not depend on A and B, so communications between C and D do not necessarily happen after that between A and B. And in the generated chart, the first hello and the second hello may be side by side, not necessary from top to down.

[bramp]

Parallel flows, and other more complex signals will be supported eventually. (loops, if/else, etc).

[broofa]

Big thumbs up on this. Now that async-await is a thing in ES6, asynchronous flows are more the norm than the exception. Being able to diagram such flows would be really slick.

If I may offer a suggestion for a possible approach to this:

• Denote Async blocks using indentation, with each block starting with a :(block name) line (with block name being optional)
• Async blocks flow sequentially with events above/below them
• Adjacent async blocks flow in parallel to one another
• Async blocks can be nested

For example:

X->B: XB
  :BA sequence
  B->A: BA
  A->B: BA_ack
  :BD sequence
  B->D: BD
    :DC sequence
    D->C: DC
    C->D: DC_ack
    :DE sequence
    D->E: DE
    E->D: DE_ack
  D->B: BD_ack
B->X: XB_ack

Would render as:

X            A            B            C           D            E
|------------|------------|------------|-----------|------------|
| > XB -----------------> |            |           |            |
|            | < BA ----< | > BD ----------------> |            |
|            | > BA_ack > |             < DC ----< | > DE ----> |
|                         |             > DC_ack > | < DE_ack < 
|                         | < BD__ack -----------< |
|< XB_ack --------------< |

(Note: A nice enhancement would be to label the block if a block name is provided.)