Jordan Johnson wrote at 02/07/2012 06:50 PM:
I'm using web-server/templates to generate text, and the data in variables I reference in the
template include s-exps that may, in some cases, contain image% objects. I want it to render
the image%s as plain text; even just the string "<IMAGE>" or similar would be
adequate.
I don't know about "web-server/templates", but if you want to do this
translation at the last minute, rather than simply avoiding putting
invalid values in the s-expression in the first place, another library
will do it:
#lang racket/base
(require (planet neil/html-writing:1:0))
(define-struct some-image-thing (x))
(define (my-html-writing-filter context thing)
(cond ((some-image-thing? thing)
(format "<IMAGE ~S>" (some-image-thing-x thing)))
(else
(error 'my-html-writing-filter
"Don't know how to filter ~S in context ~S"
thing
context))))
(write-html
`(html (head (title "My Title"))
(body (@ (bgcolor "white"))
(h1 "My Heading")
(p "This is a paragraph.")
(p "This is a foreign thing: " ,(make-some-image-thing 42))
(p "This is another paragraph.")))
(current-output-port)
my-html-writing-filter)
This writes the output:
<html><head><title>My Title</title></head><body bgcolor="white"><h1>My
Heading</h1><p>This is a paragraph.</p><p>This is a foreign thing:
<IMAGE 42></p><p>This is another paragraph.</p></body></html>
I originally implemented that feature 7 years ago, for last-minute
translation of URI objects -- to output URLs as relative to the URL of
the HTML object being written, rather than absolute.
--
http://www.neilvandyke.org/
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