Yet another Lisp markup language
Common Lisp
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CL-WHO - Forked version of Edi Weitz's HTML generator with support for macro definition, XML namespaces and more

What follows is the description of some additions in this fork of CL-WHO, which are in short: Support for XML namespaces, setting of output character case, inline macros and precompiled binary output. More documentation is also available in doc/index.html.

XML namespaces

Basically, you can now use the syntax (PREFIX . TAG) in every position normally only a keyword would work. The special PREFIX values T and NIL designate using the *XML-NAMESPACE* variable as prefix and no prefix at all:

(with-html-output (*standard-output* NIL)
  ((:xsl . stylesheet) :version 1.0
    ((:xsl . template) :match "@*|node()"
      ((:xsl . copy)
        ((:xsl . apply-templates) :select "@*|node()")))))

(with-html-output (*standard-output* NIL)
  ((:p :class "foo") "Paragraph")
  ((("html" . p) (:html . "class") "foo") "Paragraph"))

Since a improper one-element list or a cons with a non-NIL CDR is now always a tag/attribute, the following examples will run successfully and generate the tag or attribute "esc:foo" respectively:

(with-html-output (*standard-output* NIL)
  ((esc . "foo") "Paragraph"))

(with-html-output (*standard-output* NIL)
  ((:p (esc . "foo") "blub") "Paragraph"))

Because changing the namespace might happen to a whole block of XML, the XMLNS macro and the *XML-NAMESPACE* and *XML-ATTRIBUTE-NAMESPACE* variables are added to make life easier. The argument to XMLNS may be a single value, or a two-argument list where the first specifies the tag and the second the attribute namespace:

(with-html-output-to-string (*standard-output* NIL)
  (xmlns NIL
    (:html :style "foo"
     (xmlns :xsl
       (:stylesheet :bar "foo")))))

is the same as:

(with-html-output-to-string (*standard-output* NIL)
  (xmlns (NIL NIL)
    (:html :style "foo"
     (xmlns (:xsl NIL)
       (:stylesheet :bar "foo")))))

The macro always sets both namespaces at the same time. Manually specified namespaces in the before mentioned syntax are not influenced by this (except when the prefix is T of course). (If you want to set only one value at a time, use the XMLNS* macro, which accepts keyword arguments :TAG and :ATTR respectively.)

Token case

To generalize the *DOWNCASE-TOKENS-P* flag, it was exchanged with *TOKEN-CASE*, with the usual values :UPCASE, :DOWNCASE (default), :CAPITALIZE and NIL for no case change. The internal macro TOKEN-CASE helps to change this inside of a template:

(with-html-output-to-string (*standard-output* NIL)
   (token-case :capitalize
     (:stylesheet :foo "foo")))))

I currently don't know if it's useful to split this into tag, attribute and prefix variants, so I'll leave it be for now.

Inline macros

Actually the above mentioned internal macros are executed using another facility, which doesn't break the stream into multiple chunks of WRITE-STRING. It doesn't use macros but functions, which are recorded in *WHO-INTERNAL-MACROS* and executed inline with the TREE-TO-TEMPLATE function. It isn't refactored and polished yet, but works good enough.

Binary output

The WITH-HTML-OUTPUT-TO-STRING-BINARY macro may be used to convert all literal strings into byte vectors according to a given external format. FLEXI-STREAMS is used to both converted literals and support output via a FLEXI-STREAM for dynamic content.

(with-html-output-binary (stream *standard-output*)
   (:p "Hello, World!"
       (str "foo"))))

Which works like the regular macro, except that now the *COMPILEP* variable (or the COMPILEP keyword) controls whether the output is converted to byte vectors.

 '(with-html-output-binary (stream *standard-output* binary :compilep T)
      (:p "Hello, World!"
          (str "foo")))))


                                         '(:UTF-8 :EOL-STYLE :LF))))
    #(60 98 111 100 121 62 60 112 62 72 101 108 108 111 44 32 87 111 114 108
      100 33)
   (LET ((#:G1465 "foo"))
     (WHEN #:G1465 (PRINC #:G1465 STREAM)))
   (WRITE-SEQUENCE #(60 47 112 62 60 47 98 111 100 121 62) BINARY)))