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).
Robby On Thu, May 23, 2013 at 1:25 PM, Greg Hendershott <[email protected] > wrote: > p.s. > > > 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, > > 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. > > On Thu, May 23, 2013 at 2:22 PM, Greg Hendershott > <[email protected]> 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: > http://lists.racket-lang.org/users >
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