<div dir="ltr">Every function is jitted the first time it is called if you're running on a platform that the JIT supports (currently x86 and ARM).<div> </div><div style>Robby</div></div><div class="gmail_extra"> <div class="gmail_quote">On Thu, May 23, 2013 at 1:25 PM, Greg Hendershott <<a href="mailto:greghendershott@gmail.com" target="_blank">greghendershott@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> p.s. <div class="im"> > Also: Am I correct that the user-supplied function gets JIT-ed, and > there's no big performance hit from this? (I think the answer is no, </div>That question had mixed polarities. :) I should have written, I think the answer is No there's no big performance hit, and Yes it gets JIT-ed. <div class="HOEnZb"><div class="h5"> On Thu, May 23, 2013 at 2:22 PM, Greg Hendershott <<a href="mailto:greghendershott@gmail.com">greghendershott@gmail.com</a>> wrote: > I've never had a reason to use `dynamic-require`, but now I think I do. > > For my Frog static blog generator, I'd like to provide a light > "template" feature, where the user can override the default layout of > the main container <div> in the page. > > I have an existing function that returns an xexpr for this. So my idea > is to let the user optionally supply a `template.rkt` file that > `provide`s a function named (say) `container` that returns (listof > xexpr?). > > So I think what I want to do is something like this: > > (define (container-proc) > (define p (build-path (src-path) "template.rkt")) > (cond [(file-exists? p) > (dynamic-require p > 'container > (thunk default-container))] > [else default-container])) > > The built-in `default-container` looks something like this: > > (define (default-container bootstrap-row-class ;"row" or "row-fluid" > bodies ;listof xexpr?: main content > tocs ;listof xexpr?: TOC > tags/feeds ;listof xexpr?: tag/feed links > follow) ;listof xexpr?: Twitter, etc. > `((div ([class ,bootstrap-row-class]) > ;; Left column > (div ([id "left-sidebar"] > [class "span2 bs-docs-sidebar"]) > ,@tocs > (p nbsp)) > ;; Main column > (div ([id "content"] > [class "span8"]) > ,@bodies) > ;; Right column > (div ([id "right-sidebar"] > [class "span2"]) > ,@(tags/feeds) > ,@(follow))))) > > The user-supplied template.rkt would provide some variation on it. For > example they don't want any left column with a TOC, so they supply > this: > > ;; template.rkt > #lang racket > (provide container) > (define (container bootstrap-row-class ;"row" or "row-fluid" > bodies ;listof xexpr?: main content > tocs ;listof xexpr?: TOC > tags/feeds ;listof xexpr?: tag/feed links > follow) ;listof xexpr?: Twitter, etc. > `((div ([class ,bootstrap-row-class]) > ;; Don't want any left column; ignore `tocs` > ;; Main column > (div ([id "content"] > [class "span9"]) ;wider > ,@bodies) > ;; Right column: Tags/feeds/follow > (div ([id "right-sidebar"] > [class "span3"]) ;wider > ,@(tags/feeds) > ,@(follow))))) > > In a quick experiment this seems to work fine. I could also go further > and make this a tiny s-exp #lang, to make the end user experience even > simpler. But meanwhile, and before that, I just want to make sure that > `dynamic-require` is a reasonable way to do this? Does anyone > disagree? > > Also: Am I correct that the user-supplied function gets JIT-ed, and > there's no big performance hit from this? (I think the answer is no, > because from reviewing Racket's own source, I got the impression that > all modules are built on dynamic-require, but I might have > understood.) > > Thank you in advance for any advice or suggestions! ____________________ Racket Users list: <a href="http://lists.racket-lang.org/users" target="_blank">http://lists.racket-lang.org/users</a> </div></div></blockquote></div> </div>