open-ring-nrepl.el

(defun parent-directory (dir)
  (unless (equal "/" dir)
	(file-name-directory (directory-file-name dir))))

(defun find-nearest-file (dir-path filename)
  (let ((file (concat dir-path filename))
		(parent (parent-directory (expand-file-name dir-path))))
	(if (file-exists-p file)
		file
	  (when parent
		(find-nearest-file parent filename)))))

(defun current-buffer-project-clj ()
  (find-nearest-file (file-name-directory (buffer-file-name)) "project.clj"))

(defmacro with-clj-buffer (filepath &rest body)
  `(with-temp-buffer
	 (insert-file-contents ,filepath)
	 ,@body))

(defmacro let-if (varname condition-expr true-part &optional false-part)
  `(let
	   ((,varname ,condition-expr))
	 (if ,varname
		 ,true-part
	   ,false-part)))

(defun guess-ring-nrepl-port (filepath)
  (with-clj-buffer filepath
				   (beginning-of-buffer)
				   (if (and
						(re-search-forward ":nrepl" nil t)
						(re-search-forward ":port" nil t))
					   (progn
						 (forward-word)
						 (thing-at-point 'word)))))

(defun open-current-clj-project-ring-nrepl () (interactive) 
  (let-if project-file-path
		  (current-buffer-project-clj)
		  (let-if ring-nrepl-port
				  (guess-ring-nrepl-port project-file-path)
				  (nrepl "127.0.0.1" ring-nrepl-port)
				  (error "Port specification is not found."))
		  (error "project.clj is not found.")))