https://ask.clojure.org/index.php/tag/discard+literal https://ask.clojure.org/index.php/14761/clojure-supplied-functions-tagged-literal-discarded-discard <p>According to edn-format/edn specification </p> <blockquote><p>A reader should not call user-supplied tag handlers during the processing of the element to be discarded.</p> </blockquote> <p>But with clojure.edn/read and its derivatives execute provided reader functions under discard tag:</p> <pre><code>user=&gt; (clojure.edn/read-string {:readers {'foo (fn [val] (prn "!!!") val)}} "#_ #foo [1 2 3]") "!!!" Execution error at user/eval216 (REPL:1). EOF while reading </code></pre> <p>The same happen with clojure.core/read and its derivatives:</p> <pre><code>user=&gt; (binding [*data-readers* {'foo (fn [val] (prn "!!!") val)}] (read-string "#_ #foo [1 2 3]")) "!!!" Execution error at user/eval146 (REPL:1). EOF while reading </code></pre> <p>I understand that Clojure' reader does not provide explicit description of what is executed during reading out form to be discarded except "The form following #_ is completely skipped by the reader." but I think it is worth to mention that here.</p> <p>After realisation that this post is not qualifies as "ask"</p> <p>To summarize:<br> Is this a bug in clojure edn specification implementation?<br> Is the edn specification no longer accurate?</p> Syntax and reader https://ask.clojure.org/index.php/14761/clojure-supplied-functions-tagged-literal-discarded-discard Thu, 20 Nov 2025 14:57:19 +0000