;;; ob-oz.el --- org-babel functions for Oz evaluation
;; Copyright (C) 2009 Torsten Anders and Eric Schulte
;; Author: Torsten Anders and Eric Schulte
;; Keywords: literate programming, reproducible research
;; Homepage: http://orgmode.org
;; Version: 0.02
;;; License:
;; This program 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, or (at your option)
;; any later version.
;;
;; This program 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; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;; Commentary:
;; Org-Babel support for evaluating Oz source code.
;;
;; Oz code is always send to the Oz Programming Environment (OPI), the
;; Emacs mode and compiler interface for Oz programs. Therefore, only
;; session mode is supported. In practice, non-session code blocks are
;; handled equally well by the session mode. However, only a single
;; session is supported. Consequently, the :session header argument is
;; ignored.
;;
;; The Org-babel header argument :results is interpreted as
;; follows. :results output requires the respective code block to be
;; an Oz statement and :results value requires an Oz
;; expression. Currently, results are only supported for expressions
;; (i.e. the result of :results output is always nil).
;;
;; Expression evaluation happens synchronously. Therefore there is an
;; additional header argument :wait-time <number>, which specifies the
;; maximum time to wait for the result of a given expression. nil
;; means to wait as long as it takes to get a result (potentially wait
;; forever).
;;
;; NOTE: Currently the copyright of this file may not be in a state to
;; permit inclusion as core software into Emacs or Org-mode.
;;; Requirements:
;; - Mozart Programming System, the implementation of the Oz
;; programming language (http://www.mozart-oz.org/), which includes
;; the major mode mozart for editing Oz programs.
;;
;; - StartOzServer.oz which is located in the contrib/scripts
;; directory of the Org-mode repository
;;; TODO:
;; - Decide: set communication to \\switch -threadedqueries?
;;
;; - Only start Oz compiler when required, e.g., load Org-babel only when needed?
;;
;; - Avoid synchronous evaluation to avoid blocking Emacs (complex
;; Strasheela programs can take long to find a result..). In order
;; to cleanly map code blocks to their associated results (which can
;; arrive then in any order) I could use IDs
;; (e.g. integers). However, how do I do concurrency in Emacs Lisp,
;; and how can I define org-babel-execute:oz concurrently.
;;
;; - Expressions are rarely used in Oz at the top-level, and using
;; them in documentation and Literate Programs will cause
;; confusion. Idea: hide expression from reader and instead show
;; them statement (e.g., MIDI output statement) and then include
;; result in Org file. Implementation: for expressions (:results
;; value) support an additional header argument that takes arbitrary
;; Oz code. This code is not seen by the reader, but will be used
;; for the actual expression at the end. Alternative: feed all
;; relevant code as statement (:results output), then add expression
;; as extra code block which outputs, e.g., file name (so the file
;; name must be accessible by global var), but the code of this
;; extra codeblock is not seen. Hm, in that case it might be even
;; more easy to manually add this link to the Org file.
;;
(require 'ob)
;;; major mode for editing Oz programs
(require 'mozart)
;;
;; Interface to communicate with Oz.
;; (1) For statements without any results: oz-send-string
;; (2) For expressions with a single result: oz-send-string-expression
;; (defined in org-babel-oz-ResultsValue.el)
;;
;; oz-send-string-expression implements an additional very direct
;; communication between Org-babel and the Oz compiler. Communication
;; with the Oz server works already without this code via the function
;; oz-send-string from mozart.el.in, but this function does not get
;; back any results from Oz to Emacs. The following code creates a
;; socket for sending code to the OPI compiler and results are
;; returned by the same socket. On the Oz side, a socket is opened and
;; conected to the compiler of the OPI (via oz-send-string). On the
;; Emacs side, a connection to this socket is created for feeding code
;; and receiving results. This additional communication channel to the
;; OPI compiler ensures that results are returned cleanly (e.g., only
;; the result of the sent code is returned, no parsing or any
;; processing of *Oz Emulator* is required).
;;
;; There is no buffer, nor sentinel involved. Oz code is send
;; directly, and results from Oz are send back, but Emacs Lisp
;; requires a filter function for processing results.
(defvar org-babel-oz-server-dir
(file-name-as-directory
(expand-file-name
"contrib/scripts"
(file-name-as-directory
(expand-file-name
"../../.."
(file-name-directory (or load-file-name buffer-file-name))))))
"Path to the contrib/scripts directory in which
StartOzServer.oz is located.")
(defvar org-babel-oz-port 6001
"Port for communicating with Oz compiler.")
(defvar org-babel-oz-OPI-socket nil
"Socket for communicating with OPI.")
(defvar org-babel-oz-collected-result nil
"Aux var to hand result from org-babel-oz-filter to oz-send-string-expression.")
(defun org-babel-oz-filter (proc string)
"Processes output from socket org-babel-oz-OPI-socket."
;; (setq org-babel-oz-collected-results (cons string org-babel-oz-collected-results))
(setq org-babel-oz-collected-result string)
)
(defun org-babel-oz-create-socket ()
(message "Create OPI socket for evaluating expressions")
;; Start Oz directly
(run-oz)
;; Create socket on Oz side (after Oz was started).
(oz-send-string (concat "\\insert '" org-babel-oz-server-dir "StartOzServer.oz'"))
;; Wait until socket is created before connecting to it.
;; Quick hack: wait 3 sec
;;
;; extending time to 30 secs does not help when starting Emacs for
;; the first time (and computer does nothing else)
(sit-for 3)
;; connect to OPI socket
(setq org-babel-oz-OPI-socket
;; Creates a socket. I/O interface of Emacs sockets as for processes.
(open-network-stream "*Org-babel-OPI-socket*" nil "localhost" org-babel-oz-port))
;; install filter
(set-process-filter org-babel-oz-OPI-socket #'org-babel-oz-filter)
)
;; communication with org-babel-oz-OPI-socket is asynchronous, but
;; oz-send-string-expression turns is into synchronous...
(defun oz-send-string-expression (string &optional wait-time)
"Similar to oz-send-string, oz-send-string-expression sends a string to the OPI compiler. However, string must be expression and this function returns the result of the expression (as string). oz-send-string-expression is synchronous, wait-time allows to specify a maximum wait time. After wait-time is over with no result, the function returns nil."
(if (not org-babel-oz-OPI-socket)
(org-babel-oz-create-socket))
(let ((polling-delay 0.1)
result)
(process-send-string org-babel-oz-OPI-socket string)
;; wait for result
(if wait-time
(let ((waited 0))
(unwind-protect
(progn
(while
;; stop loop if org-babel-oz-collected-result \= nil or waiting time is over
(not (or (not (equal org-babel-oz-collected-result nil))
(> waited wait-time)))
(progn
(sit-for polling-delay)
;; (message "org-babel-oz: next polling iteration")
(setq waited (+ waited polling-delay))))
;; (message "org-babel-oz: waiting over, got result or waiting timed out")
;; (message (format "wait-time: %s, waited: %s" wait-time waited))
(setq result org-babel-oz-collected-result)
(setq org-babel-oz-collected-result nil))))
(unwind-protect
(progn
(while (equal org-babel-oz-collected-result nil)
(sit-for polling-delay))
(setq result org-babel-oz-collected-result)
(setq org-babel-oz-collected-result nil))))
result))
(defun org-babel-expand-body:oz (body params)
(let ((vars (mapcar #'cdr (org-babel-get-header params :var))))
(if vars
;; prepend code to define all arguments passed to the code block
(let ((var-string (mapcar (lambda (pair)
(format "%s=%s"
(car pair)
(org-babel-oz-var-to-oz (cdr pair))))
vars)))
;; only add var declarations if any variables are there
(mapconcat #'identity
(append (list "local") var-string (list "in" body "end"))
"\n"))
body)))
(defun org-babel-execute:oz (body params)
"Execute a block of Oz code with org-babel. This function is
called by `org-babel-execute-src-block' via multiple-value-bind."
(let* ((result-params (cdr (assoc :result-params params)))
(full-body (org-babel-expand-body:oz body params))
(wait-time (plist-get params :wait-time)))
;; actually execute the source-code block
(org-babel-reassemble-table
(cond
((member "output" result-params)
(message "Org-babel: executing Oz statement")
(oz-send-string full-body))
((member "value" result-params)
(message "Org-babel: executing Oz expression")
(oz-send-string-expression full-body (or wait-time 1)))
(t (error "either 'output' or 'results' must be members of :results.")))
(org-babel-pick-name (cdr (assoc :colname-names params))
(cdr (assoc :colnames params)))
(org-babel-pick-name (cdr (assoc :roname-names params))
(cdr (assoc :rownames params))))))
;; This function should be used to assign any variables in params in
;; the context of the session environment.
(defun org-babel-prep-session:oz (session params)
"Prepare SESSION according to the header arguments specified in PARAMS."
(error "org-babel-prep-session:oz unimplemented"))
;; TODO: testing... (copied from org-babel-haskell.el)
;; (defun org-babel-prep-session:oz (session params)
;; "Prepare SESSION according to the header arguments specified in PARAMS."
;; (save-window-excursion
;; (org-babel-oz-initiate-session session)
;; (let* ((vars (org-babel-ref-variables params))
;; (var-lines (mapconcat ;; define any variables
;; (lambda (pair)
;; (format "%s=%s"
;; (car pair)
;; (org-babel-ruby-var-to-ruby (cdr pair))))
;; vars "\n"))
;; (vars-file (concat (make-temp-file "org-babel-oz-vars") ".oz")))
;; (when vars
;; (with-temp-buffer
;; (insert var-lines) (write-file vars-file)
;; (oz-mode)
;; ;; (inferior-oz-load-file) ; ??
;; ))
;; (current-buffer))))
;;
;; TODO: testing... (simplified version of def in org-babel-prep-session:ocaml)
;;
;; BUG: does not work yet. Error: ad-Orig-error: buffer none doesn't exist or has no process
;; UNUSED DEF
(defun org-babel-oz-initiate-session (&optional session params)
"If there is not a current inferior-process-buffer in SESSION
then create. Return the initialized session."
(unless (string= session "none")
;; TODO: make it possible to have multiple sessions
(save-window-excursion
;; (run-oz)
(get-buffer oz-compiler-buffer))))
(defun org-babel-oz-var-to-oz (var)
"Convert an elisp var into a string of Oz source code
specifying a var of the same value."
(if (listp var)
;; (concat "[" (mapconcat #'org-babel-oz-var-to-oz var ", ") "]")
(eval var)
(format "%s" var) ; don't preserve string quotes.
;; (format "%s" var)
))
;; TODO:
(defun org-babel-oz-table-or-string (results)
"If the results look like a table, then convert them into an
Emacs-lisp table, otherwise return the results as a string."
(error "org-babel-oz-table-or-string unimplemented"))
(provide 'ob-oz)
;;; org-babel-oz.el ends here