December 2007 - parenscript-devel - mailman3.common-lisp.net

[parenscript-devel] Generating HTML in parenscript
by Gary King 25 Nov '08

25 Nov '08

I've just started playing with Parenscript and feel confused about HTML generation. Since Parenscript already includes (the unexported) process-html-forms, it seems to be able to (almost) handle much of the logic for simple HTML generation. Consider that > (parenscript::process-html-forms > `(:html > (:head (:title "ParenScript tutorial: 1st example")) > (:body (:h1 "ParenScript tutorial: 1st example") > (:p "Please click the link below." :br > ((:a :href "#" :onclick ,(ps-inline > (alert "Hello World"))) > "Hello World"))))) produces > (+ "<html/><head><title>ParenScript tutorial: 1st example</title></ > head><body><h1>ParenScript tutorial: 1st example</h1><p>Please click > the link below.<br/><a href=\"#\" onclick=\"javascript:alert(\"Hello > World\")\">Hello World</a></p></body>") It's easy to refactor process-html-forms to arrive at the (slightly incorrect) HTML in a string: > "<html/><head><title>ParenScript tutorial: 1st example</title></ > head><body><h1>ParenScript tutorial: 1st example</h1><p>Please click > the link below.<br/><a href=\"#\" onclick=\"javascript:alert(\"Hello > World\")\">Hello World</a></p></body>" and probably easy to futz with *js-inline-string-delimiter* and the like to get the correct quotes around the body of the onclick handler. So... since Parenscript doesn't do this, I have to ask "Why not"?! It would be nice to use Parenscript for simple HTML generation without having to get (Portable) AServe or some other more full-featured HTML generator. Am I missing something? thanks, -- Gary Warren King, metabang.com Cell: (413) 559 8738 Fax: (206) 338-4052 gwkkwg on Skype * garethsan on AIM

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[parenscript-devel] Lisp-like shadowing behavior
by Daniel Gackle 18 Apr '08

18 Apr '08

Below is a ps macro that simulates the shadowing of special variables in Lisp. I'm wondering if anyone thinks this would be useful to add to Parenscript. I wrote it because I have some Javascript functions that reference global variables, and wanted to write some test functions for those without modifying global state. One option of course would be to simply write the original functions to take parameters instead of the global variables. But that complicates their signatures and I'm loath to modify production code to suit tests. With this macro, my test can do this: (ps (shadow-let ((*global-var* "test value")) (function-that-uses-global-var))) and the original value of *global-var* will be restored: var _js3778 = null; try { _js3778 = GLOBALVAR; GLOBALVAR = 'test value'; functionThatUsesGlobalVar(); } finally { GLOBALVAR = _js3778; }; Daniel ------------------------------------------------------------------------ (defpsmacro shadow-let (bindings &body body) (labels ((wrap-expr (bindings body) (if (null bindings) body (list (list 'temporarily-bind (car bindings) (wrap-expr (cdr bindings) body)))))) `(macrolet ((temporarily-bind ((var expr) body) (with-ps-gensyms (temp) `(progn (defvar ,temp nil) (try (progn (setf ,temp ,var) (setf ,var ,expr) ,@body) (:finally (setf ,var ,temp))))))) ,(cons 'progn (wrap-expr bindings body)))))

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[parenscript-devel] Bug in setf
by Daniel Gackle 31 Jan '08

31 Jan '08

There's a bug when using setf to decrement a variable: (ps (setf x (- x 1 2))) => "x -= 1 - 2;" Note that this works correctly: (ps (setf x (- 1 x 2))) => "x = 1 - x - 2;" Dan

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