Pinpointer is yet another spec error reporter with sophisticated error analysis.
Notice: Pinpointer is built on top of clojure.spec, which is one of the most actively developed new features of Clojure. So, it's very fragile by nature, and its APIs are also highly subject to change.
Pinpointer heavily uses spectrace, a fine-grained spec error analyzer, to analyze the errors and report them as precise as possible.
Add the following to your :dependencies:
clojure.spec(.alpha) provides an API named explain, which (as its name suggests) explains which part of the code causes a spec error:
=> (s/def ::x integer?)
:user/x
=> (s/def ::y string?)
:user/y
=> (s/explain (s/keys :req-un [::x ::y]) {:y 1})
In: [:y] val: 1 fails spec: :user/y at: [:y] predicate: string?
val: {:y 1} fails predicate: (contains? % :x)
:clojure.spec.alpha/spec #object[clojure.spec.alpha$map_spec_impl$reify__695 0x47cb4017 "clojure.spec.alpha$map_spec_impl$reify__695@47cb4017"]
:clojure.spec.alpha/value {:y 1}
nil
=>As you can see, however, the result of explain doesn't look very human-friendlily formatted, and it's likely to take a while to find out where the actual problem is.
Pinpointer provides APIs compatible with explain and displays the problematic parts in an easier-to-grasp manner:
=> (require '[pinpointer.core :as p])
nil
=> (p/pinpoint (s/keys :req-un [::x ::y]) {:y 1})
Detected 2 spec errors:
----------------------------------------------------------------------
(1/2)
Input: {:y 1}
^^^^^^
Expected: (fn [%] (contains? % :x))
----------------------------------------------------------------------
(2/2)
Input: {:y 1}
^
Expected: string?
----------------------------------------------------------------------
nil
=>You can also colorize the report by adding the option {:colorize :ansi}:
If you'd rather like to completely replace the explain facility for any kinds of spec error reporting, it would be helpful to replace s/*explain-out* with pinpointer.core/pinpoint-out instead:
=> (set! s/*explain-out* p/pinpoint-out)
#function[pinpointer.core/pinpoint-out]
=>
;; from now on, p/pinpoint-out will be used in place of s/explain-printer
=>
=> (defn f [x] (inc x))
#'user/f
=> (s/fdef f
:args (s/cat :x (s/and integer? even?))
:ret (s/and integer? odd?))
user/f
=> (require '[clojure.spec.test.alpha :as t])
nil
=> (t/instrument)
[user/f]
=> (f 3)
ExceptionInfo Call to #'user/f did not conform to spec:
Detected 1 spec error:
----------------------------------------------------------------------
(1/1)
Input: (3)
^
Expected: even?
----------------------------------------------------------------------
clojure.core/ex-info (core.clj:4725)
=>Copyright © 2016 Shogo Ohta
Distributed under the Eclipse Public License either version 1.0 or (at your option) any later version.