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

;; Copyright (C) 2009-2016 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

;; Requirements:

;; - clojure (at least 1.2.0)
;; - clojure-mode
;; - either cider 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

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

(declare-function cider-current-connection "ext:cider-client" (&optional type))
(declare-function cider-current-session "ext:cider-client" ())
(declare-function nrepl-dict-get "ext:nrepl-client" (dict key))
(declare-function nrepl-sync-request:eval "ext:nrepl-client"
		  (input connection session &optional ns))
(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)))
(defvar org-babel-clojure-nrepl-timeout 10)

(defcustom org-babel-clojure-backend
  (cond ((featurep 'cider) 'cider)
	(t 'slime))
  "Backend used to evaluate Clojure code blocks."
  :group 'org-babel
  :type '(choice
	  (const :tag "cider" cider)
	  (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))))
    (if (or (member "code" result-params)
	    (member "pp" result-params))
	(format "(clojure.pprint/pprint (do %s))" body)
      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))
	result)
    (case org-babel-clojure-backend
      (cider
       (require 'cider)
       (let ((result-params (cdr (assoc :result-params params))))
	 (setq result
	       (nrepl-dict-get
		(let ((nrepl-sync-request-timeout org-babel-clojure-nrepl-timeout))
		  (nrepl-sync-request:eval
		   expanded (cider-current-connection) (cider-current-session)))
		(if (or (member "output" result-params)
			(member "pp" result-params))
		    "out"
		  "value")))))
      (slime
       (require 'slime)
       (with-temp-buffer
	 (insert expanded)
	 (setq result
	       (slime-eval
		`(swank:eval-and-grab-output
		  ,(buffer-substring-no-properties (point-min) (point-max)))
		(cdr (assoc :package params)))))))
    (org-babel-result-cond (cdr (assoc :result-params params))
      result
      (condition-case nil (org-babel-script-escape result)
	(error result)))))

(provide 'ob-clojure)

;;; ob-clojure.el ends here