SXML

SXML representation and HTML/XML serialization.

(import (sigil sxml))

SXML Format

SXML is an S-expression representation of XML/HTML documents. Elements are lists starting with a tag symbol, with optional attributes in an (@) form.

;; Simple element
'(p "Hello, world!")

;; Element with attributes
'(div (@ (class "main") (id "content")) "Hello")

;; Nested elements
'(ul (li "One") (li "Two") (li "Three"))

sxml->html

Convert an SXML tree to an HTML string. Void elements like <br> and <img> are output without a closing slash. Content inside <style> and <script> tags is not escaped.

(sxml->html '(p "Hello"))
; => "<p>Hello</p>"

(sxml->html '(div (@ (class "main")) (p "text")))
; => "<div class=\"main\"><p>text</p></div>"

;; Void elements use HTML style (no closing slash)
(sxml->html '(br))
; => "<br>"

(sxml->html '(img (@ (src "photo.jpg"))))
; => "<img src=\"photo.jpg\">"

;; Document wrapper is stripped
(sxml->html '(document (p "From markdown")))
; => "<p>From markdown</p>"

sxml->xml

Convert an SXML tree to an XML string. Void elements use self-closing syntax with />.

(sxml->xml '(item (@ (id "1")) "Content"))
; => "<item id=\"1\">Content</item>"

;; Void elements use XML style
(sxml->xml '(img (@ (src "photo.jpg"))))
; => "<img src=\"photo.jpg\" />"

xml-escape

Escape special XML characters (&, <, >, ", ') in text.

(xml-escape "Tom & Jerry")   ; => "Tom & Jerry"
(xml-escape "<script>")      ; => "&lt;script&gt;"
(xml-escape "She said \"hi\"")  ; => "She said &quot;hi&quot;"

Element Inspection

Examine the structure of SXML elements.

(sxml-element? '(div "hello"))  ; => #t
(sxml-element? "text")          ; => #f

(sxml-tag '(div (@ (class "box")) "content"))
; => div

(sxml-attributes '(div (@ (id "main") (class "box")) "text"))
; => ((id "main") (class "box"))

(sxml-attributes '(p "text"))
; => ()

(sxml-content '(div (@ (id "main")) "hello" " " "world"))
; => ("hello" " " "world")

Attribute Utilities

Look up or modify attributes on SXML elements.

;; Get attribute value
(sxml-attr-ref '(div (@ (id "main"))) 'id)     ; => "main"
(sxml-attr-ref '(div (@ (id "main"))) 'class)   ; => #f

;; Set attribute (returns new element)
(sxml-attr-set '(div "text") 'id "main")
; => (div (@ (id "main")) "text")

(sxml-attr-set '(div (@ (id "old"))) 'id "new")
; => (div (@ (id "new")))

Common Patterns

Building a Page

(import (sigil sxml))

(define (page title body)
  `(html
    (head (title ,title))
    (body ,@body)))

(sxml->html
  (page "My Site"
    (list
      '(h1 "Welcome")
      '(p "Hello, world!"))))

Raw HTML Content

Use *raw* to embed pre-rendered HTML without escaping:

(sxml->html
  `(div (@ (class "content"))
     (*raw* "<strong>Already formatted</strong>")))
; => "<div class=\"content\"><strong>Already formatted</strong></div>"

Inline Styles

(sxml->html
  `(style (*raw* ,(css->string
    (css ".container" (max-width "800px"))))))