http://dev.clojure.org/jira This file is an XML representation of an issue en-us 4.4 649 25-07-2011 http://dev.clojure.org/jira/browse/CLJ-1099 Clojure <p>Design discussion <a href="http://dev.clojure.org/display/design/Better+Error+Messages">here</a>.</p> <p>This patch improves Clojure's error message for a single common error: passing a non-seq where a seq is neede. More importantly, it is intended as a prototype for other similar improvements in the future.</p> <p>Error message before:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>(cons 1 2) =&gt; IllegalArgumentException Don't know how to create ISeq from: java.lang.Long </pre> </div></div> <p>Error message after:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>user=&gt; (cons 1 2) ExceptionInfo Don't know how to create ISeq from: java.lang.Long user=&gt; (ex-data *e) {:instance 2} </pre> </div></div> CLJ-1099

better error message when passing non-seq to seq

Enhancement Minor Open Unresolved Unassigned Stuart Halloway Thu, 1 Nov 2012 10:03:14 -0500 Fri, 12 Apr 2013 11:36:35 -0500 Release 1.6 0 1 <p>Wouldn't it be better to make it read "Don't know how to create ISeq from: 2 (java.lang.Long)"? How many beginners will figure<br/> out ex-data exists and how to use it?</p> <p>Hi Michael,</p> <p>ex-info messages should not, in general, pr-str things into their bodies. This raises the question of print-length and print-level in a place where the user doesn't have good control, while the whole point of ex-info is to be in the data business, not the string business. Users can control printing from ex-data any way they like.</p> <p>There are two possible ways to make beginners aware of ex-data: Tell them about it in one (or a few places) in docs, or in an infinite number of places saying "This would have been useful here, but we didn't use it because you might not know about it." I prefer the former.</p> <p>That said, I think it would be great to increase the visibility of ex-info and ex-data early on in documentation for beginners, and to make sure that things like exception printing in logs are flexible enough not to lose the benefits of ex-info.</p> Approval Ok Global Rank Patch Code