Don't allow prerequisite values for inlined functions

[marick]

It doesn't work to override functions like #'+ because they're inlined. Processing of provided should consider an attempt to do so a user error.

(defn doubler [n] (+ n n))
(fact (doubler 3) => 0 (provided (+ 3 3) => 0))   ;;; Should be rejected

In Clojure 1.3 (at least), the var for a function that will be inlined has an :inline key in its metadata.

[AlexBaranosky]

Would this be adding to (defmethod validate "fake" ...) to have it check that the function's metadata doesn't identify it is inlinable?

[AlexBaranosky]

So something like this?:

;; tst
(defn doubler [n] (+ n n))

(after-silently
  (expect (doubler 3) => 0
    (fake (+ 3 3) => 0))
  (expect @reported => (user-error-with-notes #"cannot fake the function")))

;; src
(defn- compiler-will-inline-fn? [[fn & args :as funcall]]
  (contains? (meta (var fn)) :inline))

(defmethod validate "fake" [[_fake_ & fake-form :as form]]
  (let [funcall (first fake-form)]
    (cond (not (list? funcall))
          (user-error-report-form
            form
            "The left-hand-side of a prerequisite must look like a function call."
            (cl-format nil "`~S` doesn't." funcall))

          (compiler-will-inline-fn? funcall)
          (user-error-report-form
            form
            (cl-format nil "You cannot fake the function `~S` because it is inlined by the Clojure compiler." (first funcall)))

          :else
          fake-form)))

[marick]

That seems a reasonable way to do it. Are you going to? Otherwise I will.

(I wouldn't use "fake" in the error message, since that's not a word midje.sweet exposes. Perhaps "you cannot override a call to + because the Clojure compiler inlines it.")

On Nov 5, 2011, at 8:08 PM, AlexBaranosky wrote:

So something like this?:

;; tst
(defn doubler [n] (+ n n))

(after-silently
 (expect (doubler 3) => 0
   (fake (+ 3 3) => 0))
 (expect @reported => (user-error-with-notes #"cannot fake the function")))

;; src
(defn- compiler-will-inline-fn? [[fn & args :as funcall]]
 (contains? (meta (var fn)) :inline))

(defmethod validate "fake" [[_fake_ & fake-form :as form]]
 (let [funcall (first fake-form)]
   (cond (not (list? funcall))
         (user-error-report-form
           form
           "The left-hand-side of a prerequisite must look like a function call."
           (cl-format nil "`~S` doesn't." funcall))

         (compiler-will-inline-fn? funcall)
         (user-error-report-form
           form
           (cl-format nil "You cannot fake the function `~S` because it is inlined by the Clojure compiler." (first funcall)))

         :else
         fake-form)))

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Reply to this email directly or view it on GitHub:
#60 (comment)

---

Brian Marick, Artisanal Labrador
Now working at http://path11.com
Contract programming in Ruby and Clojure
Occasional consulting on Agile

[AlexBaranosky]

I tried it out and wasn't quite sure if I had it right. You can finish it off if you'd like.

[marick]

OK, I'll take a look at it.

On Nov 6, 2011, at 6:29 PM, AlexBaranosky wrote:

I tried it out and wasn't quite sure if I had it right. You can finish it off if you'd like.

---

Reply to this email directly or view it on GitHub:
#60 (comment)

---

Brian Marick, Artisanal Labrador
Now working at http://path11.com
Contract programming in Ruby and Clojure
Occasional consulting on Agile

[marick]

In 1.3-alpha5

[AlexBaranosky]

Great! Looks like resolve was the piece I was missing.