ob-sagemath

ob-sagemath provides an org-babel integration with SageMath by sage-shell-mode. This package is inspired by ob-ipython, though the implementation is completely different.

Requirements

1. SageMath 6.6 or newer.
2. GNU Emacs 24.3 or newer.
3. sage-shell-mode

Installation and sample configuration

You can install ob-sagemath from MELPA. ob-sagemath requires sage-shell-mode. See Installation and Setup to setup sage-shell-mode. The following is a sample configuration for ob-sagemath. Put these lines in your “~/.emacs.d/init.el”.

;; Ob-sagemath supports only evaluating with a session.
(setq org-babel-default-header-args:sage '((:session . t)
                                           (:results . "output")))

;; C-c c for asynchronous evaluating (only for SageMath code blocks).
(with-eval-after-load "org"
  (define-key org-mode-map (kbd "C-c c") 'ob-sagemath-execute-async))

;; Do not confirm before evaluation
(setq org-confirm-babel-evaluate nil)

;; Do not evaluate code blocks when exporting.
(setq org-export-babel-evaluate nil)

;; Show images when opening a file.
(setq org-startup-with-inline-images t)

;; Show images after evaluating code blocks.
(add-hook 'org-babel-after-execute-hook 'org-display-inline-images)

Example file

Here is an example org file.

example.org

Session

ob-sagemath currently supports only evaluating with a session by using sage-shell-mode. So like in the sample configuration, you have to provide the :session header argument. Usually, code blocks are evaluated in the *Sage* process buffer. If the :session argument is provided and it is a string, then the code block is evaluated in another process buffer. For example, by evaluating the following code block, a process buffer *Sage<foo>* is created and the code block is evaluated in the process buffer.

#+BEGIN_SRC  sage :session foo
  print 'This code will be evaluated in the process buffer *Sage<foo>*.'
#+END_SRC

Asynchronous evaluation

You can evaluate SageMath code blocks by C-c C-c (bound to org-ctrl-c-ctrl-c) like in other org-babel packages. But usually it blocks user inputs. In the sample configuration, C-c c is bound to ob-sagemath-execute-async. And it enables the asynchronous evaluation. So you can interact with Emacs during the evaluation. With a prefix argument, it evaluates all code blocks in a buffer. If the org-mode buffer is killed during the evaluation, the output will be lost. Please do not kill the org-mode buffer until the evaluation completes.

Because org-mode doesn’t provide a standard way for asynchronous evaluation, this feature is unstable.

Images

Image files of graphs can be embedded by providing the :file header argument. By evaluating the code block, the image file is stored in the file. Here is an example.

#+BEGIN_SRC sage :file sin.png
  # You can change the size of the image by providing the figsize argument.
  plot(sin, [0, 2*pi], figsize=4)
#+END_SRC

#+RESULTS:
[[file:sin.png]]

If the :file header argument is not provided and the :results header argument contains file, then the code block returns a temporally file name. SageMath deletes these temporally files when the process exits.

#+BEGIN_SRC sage :results file
  plot(sin, [0, 2*pi])
#+END_SRC

Tables

If the :results header argument contains table and the output looks like a table (a list/tuple of lists/tuples), then the result is converted to a table.

#+BEGIN_SRC sage :results table :colnames '(Fruit Price)
  [("Apple", 300), ("Banana", 200), ("Orange", 300)]
#+END_SRC

#+RESULTS:
| Fruit  | Price |
|--------+-------|
| Apple  |   300 |
| Banana |   200 |
| Orange |   300 |

Kill evaluation

To kill the evaluation, switch to the process buffer (usually its buffer name is *Sage*), and hit C-c C-c (bound to sage-shell:interrupt-subjob).

Issues or pull requests

I am new to org-babel. There may be missing features. Feel free to post issues or send pull requests.