Missionary concept map

missionary-concept-map.md

Missionary concept map

Missionary primitives fit into three categories:

Effect descriptions = pure functional programming which is about trees not graphs

• continuous flow, m/?< (switch)
• m/watch, m/latest, m/cp
• m/observe
• m/reductions, m/relieve
• discrete flow, m/ap - switch and concat
• m/eduction — discrete flows model event streams, which are simply async sequences

Note: These are all referentially transparent primitives that construct values or "recipes" that describe effects.

Publishers = "observable sharing," this is what gets you from Tree to DAG, and is no longer pure functional

• m/signal
• m/stream
• m/memo (task)

Note:

• the difference between effect descriptions and observables is memoization, which means state
  • signal/stream return stateful objects (identity) which carry the memoization.
• this section describes the next iteration of Missionary, which is under active development as of this writing (2023 Feb 24). Leo figured out how to remove m/reactor (see leonoel/missionary#70). m/memo is new, and m/signal / m/stream no longer get a !

Ports = process coordination devices – think stateful objects, this is a form of OOP.

• Discrete ports:
  • m/dfv = mutable single assignment reference
  • m/mbx = mutable queue reference. Fire and forget. Unbounded queue. Not backpressured [bad]. like an actor (actor = process + mailbox). All actor systems have mbx. All actors are fire and forget. Lack of backpressure is a reason Rich doesn't like actors.
  • m/rdv = channel/queue with backpressure; only put one value at a time until taken
• Continuous ports:
  • atom – already exist so missionary doesn't add
    • this is a recursion primitive in practice - for cycles

Note: in Electric Clojure, ports are constructed in userland; the compiler does not emit ports. State and coordination is fully in userland control!