;;; ob-clojure.el --- org-babel functions for clojure evaluation

;; Copyright (C) 2009-2013 Free Software Foundation, Inc.

;; Author: Joel Boehland, Eric Schulte, Oleh Krehel
;;
;; Keywords: literate programming, reproducible research
;; Homepage: http://orgmode.org

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Support for evaluating clojure code, relies either on Slime or
;; on Nrepl.el for all eval.

;; Requirements:

;; - clojure (at least 1.2.0)
;; - clojure-mode
;; - either cider or nrepl.el or SLIME

;; For cider, see https://github.com/clojure-emacs/cider

;; For SLIME, the best way to install these components is by following
;; the directions as set out by Phil Hagelberg (Technomancy) on the
;; web page: http://technomancy.us/126

;; For nREPL:
;; get clojure with https://github.com/technomancy/leiningen
;; get nrepl from MELPA (clojure-mode is a dependency).

;;; Code:
(require 'ob)
(eval-when-compile
  (require 'cl))

(declare-function cider-current-ns "ext:cider-interaction" ())
(declare-function nrepl-send-string-sync "ext:nrepl-client" (input &optional ns session))
(declare-function nrepl-current-tooling-session "ext:nrepl-client" ())

(declare-function nrepl-current-connection-buffer "ext:nrepl" ())
(declare-function nrepl-eval "ext:nrepl" (body))

(declare-function slime-eval "ext:slime" (sexp &optional package))

(defvar org-babel-tangle-lang-exts)
(add-to-list 'org-babel-tangle-lang-exts '("clojure" . "clj"))

(defvar org-babel-default-header-args:clojure '())
(defvar org-babel-header-args:clojure '((package . :any)))

(defcustom org-babel-clojure-backend 'nrepl
  "Backend used to evaluate Clojure code blocks."
  :group 'org-babel
  :type '(choice
	  (const :tag "cider" cider)
	  (const :tag "nrepl" nrepl)
	  (const :tag "SLIME" slime)))

(defun org-babel-expand-body:clojure (body params)
  "Expand BODY according to PARAMS, return the expanded body."
  (let* ((vars (mapcar #'cdr (org-babel-get-header params :var)))
	 (result-params (cdr (assoc :result-params params)))
	 (print-level nil) (print-length nil)
	 (body (org-babel-trim
		(if (> (length vars) 0)
		    (concat "(let ["
			    (mapconcat
			     (lambda (var)
			       (format "%S (quote %S)" (car var) (cdr var)))
			     vars "\n      ")
			    "]\n" body ")")
		  body))))
    (cond ((or (member "code" result-params) (member "pp" result-params))
	   (format (concat "(let [org-mode-print-catcher (java.io.StringWriter.)] "
			   "(clojure.pprint/with-pprint-dispatch clojure.pprint/%s-dispatch "
			   "(clojure.pprint/pprint (do %s) org-mode-print-catcher) "
			   "(str org-mode-print-catcher)))")
		   (if (member "code" result-params) "code" "simple") body))
	  ;; if (:results output), collect printed output
	  ((member "output" result-params)
	   (format "(clojure.core/with-out-str %s)" body))
	  (t body))))

(defun org-babel-execute:clojure (body params)
  "Execute a block of Clojure code with Babel."
  (let ((expanded (org-babel-expand-body:clojure body params)))
    (case org-babel-clojure-backend
      (cider
       (require 'cider)
       (or (nth 1 (nrepl-send-string-sync
		   expanded
		   (cider-current-ns)
		   (nrepl-current-tooling-session)))
	   (error "nREPL not connected!  Use M-x cider-jack-in RET")))
      (nrepl
       (require 'nrepl)
       (if (nrepl-current-connection-buffer)
    	   (let* ((result (nrepl-eval expanded))
    		  (s (plist-get result :stdout))
    		  (r (plist-get result :value)))
    	     (if s (concat s "\n" r) r))
    	 (error "nREPL not connected!  Use M-x nrepl-jack-in RET")))
      (slime
       (require 'slime)
       (with-temp-buffer
    	 (insert expanded)
    	 ((lambda (result)
    	    (let ((result-params (cdr (assoc :result-params params))))
    	      (org-babel-result-cond result-params
    		result
    		(condition-case nil (org-babel-script-escape result)
    		  (error result)))))
	  (slime-eval
	   `(swank:eval-and-grab-output
	     ,(buffer-substring-no-properties (point-min) (point-max)))
	   (cdr (assoc :package params)))))))))

(provide 'ob-clojure)

;;; ob-clojure.el ends here