;;; rcd-template.el --- template
;; -*- lexical-binding: t; -*-


;;; Commentary:
;; 

;;; Code:

(defvar rcd-template-delimiter-open "⟦")
(defvar rcd-template-delimiter-close "⟧")

(defun rcd-template-eval (string &optional delimiters)
  "Evaluates Emacs Lisp enclosed by `rcd-template-delimiter-open' and `rcd-template-delimiter-close'.

Optional DELIMITERS list may be provided to change default
delimiters, first list member has to be the opening delimiter and
second the closing delimiter.

Space or new line has to follow `rcd-template-delimiter-open' and
precede `rcd-template-delimiter-close' for evaluation to get
invoked."
  (let* ((delimiters (or delimiters (list rcd-template-delimiter-open rcd-template-delimiter-close)))
	 (open (car delimiters))
	 (close (cadr delimiters)))
    (with-temp-buffer
      (insert string)
      (goto-char 0)
      (while (re-search-forward (rx (literal open)
				    (one-or-more (or blank "\n"))
				    (group (minimal-match (one-or-more anything)))
				    (one-or-more (or blank "\n"))
				    (literal close))
				nil t)
	;;(message "Found match")
	(let* ((lisp (car (read-from-string
			   (buffer-substring-no-properties
			    (1+ (match-beginning 0)) (1- (match-end 0))))))
	       (value (condition-case nil
			  (eval lisp)
			(error "")))
	       (value (string-or-empty-string value)))
	  ;; (message "HELLO: %s" (eval (format "%s" hello-name)))
	  (delete-region (match-beginning 0) (match-end 0))
	  (insert (format "%s" value))))
      (buffer-string))))

(defun rcd-template-buffer-eval ()
  (interactive)
  (let* ((buffer (buffer-string))
	 (mode major-mode)
	 (point (point)))
    (pop-to-buffer-same-window "Preview")
    (insert (rcd-template-eval buffer))
    (goto-char point)
    (funcall mode)
    (espeak "Preview")))

(defun string-or-empty-string (i)
  "Returns empty string for nil"
  (let* ((type (type-of i)))
    (cond ((or (eql type 'integer)
	       (eql type 'float)) 
	   (number-to-string i))
	  ((null i) "")
	  ((eql type 'symbol) (prin1-to-string i))
	  ((eql type 'string) i))))

(provide 'rcd-template)

;;; rcd-template.el ends here