support for execution of Scala code blocks

lisp/ob-scala.el

@@ -0,0 +1,119 @@
+;;; ob-scala.el --- org-babel functions for Scala evaluation
+
+;; Copyright (C) Andrzej Lichnerowicz
+
+;; Author: Andrzej Lichnerowicz
+;; Keywords: literate programming, reproducible research
+;; Homepage: http://orgmode.org
+;; Version: 0.01
+
+;;; 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:
+;; Currently only supports the external execution. No session support yet.
+
+;;; Requirements:
+;; - Scala language :: http://www.scala-lang.org/
+;; - Scala major mode :: Can be installed from Scala sources
+;;  https://github.com/scala/scala-dist/blob/master/tool-support/src/emacs/scala-mode.el
+
+
+;;; Code:
+(require 'ob)
+(require 'ob-ref)
+(require 'ob-comint)
+(require 'ob-eval)
+
+(add-to-list 'org-babel-tangle-lang-exts '("scala" . "scala"))
+(defvar org-babel-default-header-args:scala '())
+(defvar org-babel-scala-command "scala"
+  "Name of the command to use for executing Scala code.")
+
+
+(defun org-babel-execute:scala (body params)
+  "Execute a block of Scala code with org-babel.  This function is
+called by `org-babel-execute-src-block'"
+  (message "executing Scala source code block")
+  (let* ((processed-params (org-babel-process-params params))
+         (session (org-babel-scala-initiate-session (first processed-params)))
+         (vars (second processed-params))
+         (result-params (third processed-params))
+         (result-type (cdr (assoc :result-type params)))
+         (full-body (org-babel-expand-body:generic
+                     body params))
+         (result (org-babel-scala-evaluate
+                  session full-body result-type result-params)))
+
+    (org-babel-reassemble-table
+     result
+     (org-babel-pick-name
+      (cdr (assoc :colname-names params)) (cdr (assoc :colnames params)))
+     (org-babel-pick-name
+      (cdr (assoc :rowname-names params)) (cdr (assoc :rownames params))))))
+
+
+(defun org-babel-scala-table-or-string (results)
+  "Convert RESULTS into an appropriate elisp value.
+If RESULTS look like a table, then convert them into an
+Emacs-lisp table, otherwise return the results as a string."
+  (org-babel-script-escape results))
+
+
+(defvar org-babel-scala-wrapper-method
+  "(
+%s
+) asString print
+")
+
+
+(defun org-babel-scala-evaluate (session body &optional result-type result-params)
+  "Evaluate BODY in external Scala process.
+If RESULT-TYPE equals 'output then return standard output as a string.
+If RESULT-TYPE equals 'value then return the value of the last statement
+in BODY as elisp."
+  (when session (error "Sessions are not supported for Scala. Yet."))
+  (case result-type
+    (output
+     (let ((src-file (org-babel-temp-file "scala-")))
+       (progn (with-temp-file src-file (insert full-body))
+              (org-babel-eval
+               (concat org-babel-scala-command " " src-file) ""))))
+    (value 
+     (let* ((src-file (org-babel-temp-file "scala-"))
+            (wrapper (format org-babel-scala-wrapper-method body)))
+       (with-temp-file src-file (insert wrapper))
+       ((lambda (raw)
+          (if (member "code" result-params)
+              raw
+            (org-babel-scala-table-or-string raw)))
+        (org-babel-eval
+         (concat org-babel-scala-command " " src-file) ""))))))
+
+                    
+(defun org-babel-prep-session:scala (session params)
+  "Prepare SESSION according to the header arguments specified in PARAMS."
+  (error "Sessions are not supported for Scala. Yet."))
+
+(defun org-babel-scala-initiate-session (&optional session)
+  "If there is not a current inferior-process-buffer in SESSION
+then create.  Return the initialized session. Sessions are not 
+supported in Scala."
+  nil)
+
+(provide 'ob-scala)
+;;; ob-scala.el ends here