Detect Mistaken Use Of Middleware Factories about re-frame

[mike-thompson-day8]

Problem Definition
Happens if you:

• mistakenly supply undoable as middleware ...
• ... instead of correctly supplying (undoable "some explanation")

undoable is a middleware factory. You must call it (with a parameter) to get middleware.

So this ticket is asking for the mistake to be reported because its a mistake which currently passes silently, and it is a bit baffling to debug.

Solutions:
Unfortunately undoable is a function (middleware factory), just like a true middleware function would be. So detection of this mistake is a bit hard.

Doubly so because you can do this (undoable some-function) . So we can't even check at middleware composition time for a non fn parameter.

Will dwell on it.

[mike-thompson-day8]

Okay, I've figured out a way of doing this via metadata. But I'm stuck on this question:
https://groups.google.com/forum/#!topic/clojurescript/KuGrBMqzO1o

[ul]

not sure which answer will arrive faster to you, so duplicate here and in cljs group

defn attaches metadata to var:

(defn ^{:a 1} f [] true)
#<function cljs$user$f(){
return true;
}>
=> nil

(meta #'f)
=> {:ns cljs.user, :name f, :file "<cljs repl>", :end-column 16, :source "^{:a 1} f", :column 1, :line 1, :end-line 1, :arglists ([]), :doc nil, :test nil, :a 1}

note presence of :a key in the end

[mike-thompson-day8]

Fixed in 78dacf5

Will be a part of v0.4.1