html-template-devel

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html-template-devel@common-lisp.net

November 2006

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2 discussions

[html-template-devel] Additions to html-template
by Andrew Golding 22 Apr '08

22 Apr '08

Hello to all the members of this list. Recently at Onshore Development, we have started using HTML-TEMPLATE to render web-pages in an application we call Woofie, which provides an alternative interface to Webcheckout. While working on html templates for Woofie, I found myself wanting some extra abilities currently not available in HTML-TEMPLATE, mainly a foreach style loop with the variable which holds the current value of the list declared inside the tag, and the ability to use certain lisp expressions (format inside tmpl-var's and equality comparisons, boolean comparisons (or, and, etc.) inside of tmpl-if's). I would like to see if other developers would find such features useful. I currently have implemented both features I described to some degree in the following fashion: - the for-each style loop is represented in my templates as TMPL_LOOP_FOR and closed with a /TMPL_LOOP. The tag looks for two separate strings, one being the variable and the other being the list (eg. ). In the code, in each iteration of the loop over authors, a (setf (getf values :author) author) is performed (this should probably be changed into something similar to the *value-access-function*, or the perhaps *value-access-function* could be made setf'able?). - TMPL_IF and TMPL_VAR can take a symbol or a list. The list is deserialized from a string into a list of symbols or string literals delimited by double quotes. A larger expression is built by making a let, then evaluating the list. For example, the format expression in  would get expanded to: (let ((result-count (funcall *value-access-function* :result-count values)) (first-result (funcall *value-access-function* :first-result values)) (last-result (funcall *value-access-function* :last-result values))) (format nil "Displaying ~d results, displaying ~d through ~d." result-count first-result last-result)), which passed to (eval) and currently evaluated in the common lisp package (though evaluation should probably get done in some user-specified package that can be made to contain helper-functions for displaying data). I would appreciate any comments, and I will try to answer any questions should there be any (I'm guessing there will). The code can be found at http://kfreedom.onshored.com/html-template-additions.lisp , and should work with the standard html-template 0.7.0 package. Regards, Andrew Golding andy(a)onshored.com

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[html-template-devel] Proposed new feature for HTML-TEMPLATE
by Marijn Haverbeke 12 Dec '06

12 Dec '06

[I sent this to Edi earlier, but it seems to have been ignored. I just saw that there is actually a mailing list for this project, so I'm hoping that sending it to the correct place will generate a bit more response.] > For a personal project I extended your HTML-TEMPLATE library with an > extra TMPL tag. If you think my extension is useful enough to be > included in the library proper, I'll be happy to properly document it > and submit a patch. Here is how it works: > > Support for the TMPL_CALL tag is added. This is related to > TMPL_INCLUDE, but allows the values passed to a template to > 'dynamically' determine which sub-templates should be used. It was > inspired by the way XSLT's apply-templates works. The tag takes a > single symbol as argument, and treats it the way TMPL_LOOP does, > iterating over a list or a vector of values. Each of these values > specifies a template to use and a set of values to apply that template > to. These are extracted by applying the functions > *call-template-access-function* and *call-values-access-function* to > the given values - these default to #'car and #'cdr respectively. > > If *default-template-pathname* is set properly, and there are > templates named "fancy-paragraph" and "standard-footer", something > like this... > > '(:title "Title" > :body > ((#P"fancy-paragraph" :content "This is a fancy paragraph") > (#P"standard-footer"))) > > ... can be fed to a template that applies TMPL_CALL to :body to render > its body in whatever way the code that generated the values thought > suitable. > > Basically, this extension allows the use of outer templates that do > not know precisely what kind of content will be inserted into them. A > very basic example is a template that contains the <html>, <head>, & > <body> tags + maybe some basic formatting, and which can be used by > all pages that generate pages with a similar outer structure. > > Let me know what you think, > Marijn Haverbeke [Also, reading a few older message on this list suggests that adding fancy new features isn't a priority for this library -- but I still think adding a dynamic way to include subtemplates would be useful enough to warrant the extra complexity.]

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