md4tj/md4tj_parse.el

95 lines
3.1 KiB
EmacsLisp

;;; md4tj_parse --- Summary
;;; Commentary:
;;; Code:
(require 'cl-lib)
(defun getline ()
"Get current line from loaded buffer."
(buffer-substring-no-properties (line-beginning-position) (line-end-position)))
(defun md4tj-begin-tag (tag &optional attrs)
"Return beginning html tag for TAG with optional ATTRS."
(concat "<" tag
(mapconcat 'identity (cl-map 'listp (lambda (l) (concat " " (nth 0 l) "=" (nth 1 l))) attrs) "")
">"))
(defun md4tj-end-tag (tag)
"Return end html tag for TAG."
(concat "</" tag ">"))
(defun md4tj-process-header (line)
"Process LINE known to be header, return HTML."
(let ((level (length (nth 0 (split-string line)))))
(if (or (< level 0) (> level 6))
(error (concat "Error parsing: " line "\n"))
(concat (md4tj-begin-tag (concat "h" (number-to-string level)))
(mapconcat 'identity (cdr (split-string line)) " ")
(md4tj-end-tag (concat "h" (number-to-string level)))))))
(defun md4tj-process-paragraph (line)
"Process LINE that is paragraph, return HTML."
(concat (md4tj-begin-tag "p") line (md4tj-end-tag "p")))
(defun md4tj-process-line (line)
"Process all inline elements of the LINE, return HTML."
;; Finally links
(replace-regexp-in-string
"\\[\\(.*\\)\\](\\(.*\\))"
(concat (md4tj-begin-tag "a" (list '("href" "\\2"))) "\\1" (md4tj-end-tag "a"))
;; Then images
(replace-regexp-in-string
"!\\[\\(.*\\)\\](\\(.*\\))"
(md4tj-begin-tag "img" (list '("src" "\\2") '("alt" "\\1")))
;; Then emphasis
(replace-regexp-in-string
"\\*\\(.*\\)\\*"
"<em>\\1</em>"
;; Then strong
(replace-regexp-in-string
"\\*\\*\\(.*\\)\\*\\*"
"<strong>\\1</strong>"
;; First code
(replace-regexp-in-string
"`\\(.*\\)`"
"<code>\\1</code>" line))))))
;; Note: a "block" is the smallest unit of parsing
;; It is normally a line of the code, but can be
;; multiple lines in the case of a block (NI)
(defun md4tj-process-block (codeblock)
"Process CODEBLOCK and return html."
(cond ((string-match "^#+ " codeblock) (md4tj-process-header (md4tj-process-line codeblock)))
((string= "---" codeblock) "<hr>")
((= (length codeblock) 0) "<br/>")
(t (md4tj-process-paragraph (md4tj-process-line codeblock)))))
(defun md4tj-next-block ()
"Retrieve the next block in the open file."
(let ((currline (getline)))
(cond ((string-match "^- " currline) nil) ;; TODO ul's
((string-match "^[0-9]+\\. " currline) nil) ;; TODO ol's
(t currline))))
(defun md4tj-parse (mdfile outfile)
"Entry point to parse MDFILE and output to OUTFILE."
(let ((inbuf (generate-new-buffer " in"))
(outbuf (generate-new-buffer " out")))
(set-buffer inbuf)
(insert-file-contents mdfile)
(goto-char (point-min))
(set-buffer outbuf)
(while (with-current-buffer inbuf (< (point) (point-max)))
;; Insert next line(s) into output file
(insert (concat (md4tj-process-block (with-current-buffer
inbuf
(md4tj-next-block)))
"\n"))
;; Advance input file by a line
(with-current-buffer inbuf (forward-line)))
(write-region nil nil outfile nil)))
(provide 'md4tj_parse)
;;; md4tj_parse.el ends here