On Sep 1, 2007, at 13:01, Adam Spiers wrote:
Ah, I was assuming that the elisp interpreter was intelligent enough that if you did a concat of two or more constants, it would only build the regexp the first time, similar to m//o in Perl. Is that not the case? Or maybe it only performs this optimisation if you byte-compile? I found this in the elisp manual:-- Special Form: eval-when-compile body... This form marks BODY to be evaluated at compile time but not when the compiled program is loaded. The result of evaluation by the compiler becomes a constant which appears in the compiled program. If you load the source file, rather than compiling it, BODY is evaluated normally. If you have a constant that needs some calculation to produce, `eval-when-compile' can do that at compile-time. For example, (defvar my-regexp (eval-when-compile (regexp-opt '("aaa" "aba" "abb")))) Maybe I should practice what I preach and use mercurial to start an experimental branch to look at the impact on performance of doing this refactoring :-)
I made some tests a while ago, and the impact was very small. - Carsten _______________________________________________ Emacs-orgmode mailing list Emacs-orgmode@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-orgmode
