November 2007 - html-template-devel@lists.common-lisp.net

[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] Easier way to fill tmpl_var environment?
by Sohail Somani 22 Nov '07

22 Nov '07

Hi, First of all, thank you for a nice library. Now, I have a question. Is there a way to have html-template call back into the calling environment so I don't have to pass all slot values of a list of objects in as a list? So instead of: ;;; prints "b c" (fill-and-print-template "" (list :a (list :b "b" :c "c"))) I can do something like: ;;; prints "b c" (fill-and-print-template " " (list :a a)) Where b-of and c-of are readers. It is just very very tedious to make lists of all the values. Does that make any sense? Thanks for your time. -- Sohail Somani http://uint32t.blogspot.com

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[html-template-devel] Is this behaviour for SKIP-LEADING-WHITESPACE correct?
by Chaitanya Gupta 16 Nov '07

16 Nov '07

Hello, I have come across a situation where SKIP-LEADING-WHITESPACE (HTML-TEMPLATE's internal function) throws an error while trying to create a template printer. I have narrowed it down to the following - CL-USER> (let ((html-template:*ignore-empty-lines* t)) (html-template::skip-leading-whitespace (make-array 4 :element-type 'character :fill-pointer 0))) This throws an error. Here's the debugger output - Index(s) to array function is/are out of the range of the array. [Condition of type TYPE-ERROR] Restarts: 0: [ABORT-REQUEST] Abort handling SLIME request. 1: [ABORT] Abort entirely from this (lisp) process. Backtrace: 0: (SWANK::DEBUG-IN-EMACS #<TYPE-ERROR @ #x1143b6d2>) 1: (SWANK:SWANK-DEBUGGER-HOOK #<TYPE-ERROR @ #x1143b6d2> #<Function SWANK-DEBUGGER-HOOK>) 2: (ERROR TYPE-ERROR :DATUM NIL :EXPECTED-TYPE FIXNUM :FORMAT-CONTROL "Index(s) to array function is/are out of the range of the array." :FORMAT-ARGUMENTS (NIL)) 3: (HTML-TEMPLATE::SKIP-LEADING-WHITESPACE "") 4: (LET ((HTML-TEMPLATE:*IGNORE-EMPTY-LINES* T)) (HTML-TEMPLATE::SKIP-LEADING-WHITESPACE (MAKE-ARRAY 4 :ELEMENT-TYPE (QUOTE CHARACTER) :FILL-POINTER 0))) 5: (EVAL (LET ((HTML-TEMPLATE:*IGNORE-EMPTY-LINES* T)) (HTML-TEMPLATE::SKIP-LEADING-WHITESPACE (MAKE-ARRAY 4 :ELEMENT-TYPE # :FILL-POINTER 0)))) 6: (SWANK::EVAL-REGION "(let ((html-template:*ignore-empty-lines* t)) (html-template::skip-leading-whitespace (make-array 4 :element-type 'character :fill-pointer 0))) " T) ... [snipped remaining frames] Is the above behaviour for SKIP-LEADING-WHITESPACE correct? Thanks, Chaitanya

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