By default, CL-WHO uses single quotes for quoting XML attributes values (e.g. <h1 id='title'>Hello!</h1>). I am trying to set cl-who:*attribute-quote-char* to #\" so that attribute values use double quotes instead (e.g. <h1 id="title">Hello!</h1>). However, (setq cl-who:*attribute-quote-char #\") does not seem to have any effect when I use it in ASDF like this:
myprog.asd:
(defpackage myprog-asd
(:use :cl :asdf))
(in-package :myprog-asd)
(defsystem "myprog"
:depends-on (:cl-who)
:components ((:file "mypackage")))
mypackage.lisp:
(defpackage :mypackage
(:use :cl)
(:export :f))
(in-package :mypackage)
(setq cl-who:*attribute-quote-char* #\") ;; <- HERE.
(defun f ()
(cl-who:with-html-output (*standard-output*)
(:h1 :id "title" "Hello!")))
I am getting single quotes instead of double quotes:
$ sbcl
* (require "asdf")
* (asdf:load-asd (merge-pathnames "myprog.asd" (uiop:getcwd)))
* (asdf:load-system :myprog)
* (mypackage:f)
<h1 id='title'>Hello!</h1>
Why is (setq cl-who:*attribute-quote-char #\") not having any effect? How do I make CL-WHO print double quotes instead of single quotes?
(SBCL version: 2.2.2, CL-WHO version: 1.1.4 [commit: 0d382647])
By the way, I found that I could get double quotes by wrapping the setq in an eval-when:
(eval-when (:compile-toplevel :execute)
(setq cl-who:*attribute-quote-char* #\"))
However, I have no idea how or why this works.
This is happening because with-html-output is smart enough to spot (some, it necessarily can not spot all) cases where the generated HTML is a constant string. In those cases it just turns the whole thing into a macroexpansion-time constant. and that happens before you have assigned to the variable, which happens at load time. That's why wrapping it with (eval-when (... :compile-toplevel) ...) works.