XSLT Pseudo Implementation in Elisp

xslt-pseudo.el

(defun apply-templates (node templates)
  (let (output)
    ;; loop through each template
    (dolist (template templates output)
      ;; if the current node matches the template
      (when (matches node (car template))  
        ;; apply the template and stop processing further templates
        (setq output (apply-template node template))
        (return output)))
    ;; if no template matched, process the node's children
    (dolist (child (cdr node) output)
      (setq output (apply-templates child templates)))))

(defun apply-template (node template)
  (let (output)
    ;; loop through each instruction in our template
    (dolist (instruction (cdr template) output)
      ;; if the instruction is to output text
      (when (eq (car instruction) 'text)
        ;; add the instruction's text to our output
        (setq output (concat output (cdr instruction))))
      ;; else if the instruction is to output the value of an XPath expression
      (when (eq (car instruction) 'value-of)
        ;; evaluate the XPath expression and add its value to our output
        (setq output (concat output (evaluate-xpath (cdr instruction) node))))
      ;; else if the instruction is to apply templates to an XPath expression
      (when (eq (car instruction) 'apply-templates)
        ;; evaluate the XPath expression to get a set of nodes
        (let ((nodes (evaluate-xpath (cdr instruction) node)))
          ;; apply templates to each node and add the results to our output
          (dolist (subnode nodes output)
            (setq output (concat output (apply-templates subnode templates)))))))))

(defun matches (node pattern)
  ;; this function would implement matching of the node against a template pattern
  ;; for simplicity, it's not implemented here
  )

(defun evaluate-xpath (expression node)
  ;; this function would implement the evaluation of an XPath expression in the context of a specific node
  ;; for simplicity, it's not implemented here
  )