Clojure macros and quotes
I am trying to "get" clojure macros and write a modified version of the macro are
in terms of an existing macro are
. The setting I want is to have a signature [argv expr args]
instead of [argv expr & args]
So I tried
(defmacro are2 [argv expr args] `(clojure.test/are ~arg ~expr ~@args))
what kind of works, except that it expects an unquoted list:
(are2 [input] (= 0 input) (1 2 3))
where I would rather expect the quoted list:
(are2 [input] (= 0 input) '(1 2 3))
But this leads to:
Unable to resolve symbol: quote in this context.
If i try
(are2 [input] (= 0 input) (list 1 2 3))
and then list
itself is processed as a test case.
What I didn't understand / how do I get past a quote in a macro
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'(1 2 3)
expands into (quote (1 2 3))
, which has an extra character quote
and too many list levels, which you can see with macro instance-1:
user> (macroexpand-1 '(are2 [input] (= 0 input) '(1 2 3)))
(clojure.test/are [input] (= 0 input) quote (1 2 3))
you can remove a quote from the list by first wrapping it in an int and rest
user> (defmacro are2 [argv expr args]
`(clojure.test/are ~argv ~expr ~@(first (rest args))))
#'user/are2
user> (macroexpand-1 '(are2 [input] (= 0 input) '(1 2 3)))
(clojure.test/are [input] (= 0 input) 1 2 3)
which is then run as a test:
user> (are2 [input] (= 0 input) '(1 2 3)
FAIL in clojure.lang.PersistentList$EmptyList@1 (NO_SOURCE_FILE:1)
expected: (= 0 1)
actual: (not (= 0 1))
FAIL in clojure.lang.PersistentList$EmptyList@1 (NO_SOURCE_FILE:1)
expected: (= 0 2)
actual: (not (= 0 2))
FAIL in clojure.lang.PersistentList$EmptyList@1 (NO_SOURCE_FILE:1)
expected: (= 0 3)
actual: (not (= 0 3))
false
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