Interpreter return IllegalArgumentException rather than nil.

[ribelo]

If the argument of the function returned by the interpreter is vector, it throws an exception if the query is unsolved.

(let [f (mi/finder
         ['?x '?y] "a")]
  (f {:a 1}))
;; => nil

(let [f (mi/finder
         ['?x '?y] "a")]
  (f [:a 1]))
;; => error: java.lang.ClassCastException: class java.lang.String cannot be cast
;; to class clojure.lang.IFn (java.lang.String is in module java.base of loader
;; 'bootstrap'; clojure.lang.IFn is in unnamed module of loader 'app')

[jimmyhmiller]

The second argument to mi/finder is supposed to be a function that will be passed the bindings (in this case it is the string "a"). The interpreter is trying to call that string as if it is a function.

If you wanted to use a pattern on the rhs try mi/rewriter instead.

(We might want to consider catching this instead of throwing the error deep down like this)

[noprompt]

Should we throw in some asserts for the arguments?

[noprompt]

Closing pending a patch or plan of action.