Eric Dvorsak yenda

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

Here's a mechanism for transforming a discrete input flow into an output flow where the internal process state can be implemented with loop/recur. As an example I provide an implementation of "batching with both a maximum size and a maximum delay" referenced in leonoel/missionary#109.

Transforming discrete flows

A common pattern for discrete flows is that we want to create an output flow from an input flow, where:

	;; All our model functions adhere to simple interface, taking any number of arguments,
	;; but always the `:cofx` map as an last argument and producing map of effects (or nothing)
	;; as result:
	(defn effects-fn [arg1 arg2 {:keys [db] :as cofx}]
	{:db (update db :some-key arg1)
	:http-call ...})

	;; We have both `merge-fx` macro and `merge-effect` functions at our disposal
	;; Whenever we do static merging of effects, we use the former:
	(defn final-effects-fn [cofx]

	;; Newer version at https://gist.github.com/awwx/6d02e6ea702bdc499bcf847e9b9bb98f

	(ns mobserve
	(:require
	[missionary.core :as m]))

	;; Encapsulate differences between Clojure and ClojureScript
	;; on how IFn and IDeref are implemented.

	#?(:clj