Confusion about symbols

colinkahn · August 18, 2018, 7:28pm

Hi,

I was playing around with writing a macro over the spec.test/check function and couldn’t figure out why one approach was working and the other didn’t.

gist.github.com

https://gist.github.com/colinkahn/dff9f01107fdd7e92ea3191653e628d2

symbol-confusion.clj

(require '[clojure.spec.test.alpha :as st])
(require '[clojure.spec.alpha :as s])
(require '[expound.alpha :as expound])

;; Two macros, one that quotes tmp-sym in the call to `st/check`...
(defmacro check1 [sym tmp-sym & gen-body]
  `(do
     (def ~tmp-sym ~sym)
     (s/fdef ~tmp-sym ~@gen-body)
     (st/check (quote ~tmp-sym))

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My assumption would be that since macroexpand-1 returns the same results they would work the same, but this isn’t the case.

Any help would be greatly appreciated.

j-cr · August 20, 2018, 9:02am

in check2, you pass a namespaced symbol, and in check1 you pass a non-namespaced symbol

(didn’t run your code, but I would guess that’s the problem)

colinkahn · August 20, 2018, 1:41pm

I thought that might be the case, but wasn’t sure since when I macroexpand check1 it does namespace the symbol.

Is there an alternative to quote that namespaces? I tried a nested backtick but that would just give me a namespaced tmp-sym symbol.

system · February 19, 2019, 1:41am

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