From Spec to Test Suite in Common Lisp: Mustache

Fairly idiomatic code. Just minor nitpick.<p>To traverse directories use fad:walk-directory from CL-FAD. It takes a starting directory and a single-argument function, then traversing that directory <i>recursively</i> calling the function with each child as an argument.<p>I wrote this earlier to count what languages I've used in 2011, because I didn't trust my cursory examination with ls(1).<p><pre><code> (let ((start-2011 (encode-universal-time 1 0 0 1 1 2011)) (lang-stat (make-hash-table :test #'equalp))) (fad:walk-directory #p"~/hack" (lambda (f) (when (&#62;= (file-write-date f) start-2011) (when-let (type (string-trim "~" (pathname-type f))) (incf (gethash type lang-stat 0)))))) (loop for k in (sort (hash-table-keys lang-stat) #'string-lessp) do (format t "~a~10t~a~%" k (gethash k lang-stat 0))))</code></pre>

I'm not a lisp pro (more like aspiring to be), but, for what it's worth, I think your use of eval is fine. It doesn't suffer from the "double evaluation" problem, and evaluation at compile time is actually what you want.<p>If you really want to get rid of eval in the macro, though, I suppose you could hard-code your loop to all-specs rather than attempt to supply the list as an argument. This would be contingent on all-specs being present in the compilation environment, via an eval-when or something.

That's a pretty neat article! I'm glad you wrote that up! (Didn't even notice the EVAL in there, until I saw wes-exp's comment: You can avoid it (if you want, seeing as this is example code) by not using a SPECS variable, and putting <i>all-specs</i> in the loop directly.