Introduction

ob-janet provides Org Babel support for the Janet language to enable Janet code blocks in literate Org files.

Installation

Manual Installation

Download ob-janet.el, place it in the load path, and add a require to your init file. It may be necessary to set or customize ob-janet-path and ob-janet-executable if either can't be found by default.

(require 'ob-janet)
(add-to-list 'org-babel-load-languages '(janet . t))

via use-package

(use-package ob-janet
  :after org
  :init
    (setq ob-janet-executable "janet"
          ob-janet-path "/usr/local/lib/janet")
  :config
    (add-to-list 'org-babel-load-languages '(janet . t)))

via straight.el

(use-package ob-janet
  :straight (:host github :repo "zzkt/ob-janet")
  :after org
  :config
  (add-to-list 'org-babel-load-languages '(janet . t)))

Usage

Execute a code block with C-c C-c using the header :results output to capture stdout, or :results value to capture the return value of the block.

(var void 'boundless)
(print "I live in a boundless void.")
(string "The void is " void)

(var void 'boundless)
(print "I live in a boundless void.")
(string "The void is " void)

Variables can be passed from named Org blocks (including tables) or assigned in the header

Name	Age
Eleanor	36
Jason	29
Kamilah	31

(each row data
  (print (string "Name: " (row 0) ", Age: " (row 1))))

(print (+ x y))

Header arguments

Header	Description	Default
:cmd <path>	Janet executable or path	janet
:results <format>	Result format: raw, none, output or value	output
:session <name>	Session name for persistent eval	none
:file <path>	Output file path	none
:prologue <code>	Code to prepend before the body	none
:epilogue <code>	Code to append after the body	none
:debug	Show expanded body	none

Sessions

Use :session for persistent state (sessions) across code blocks that share the same session name

(var *count* 0)
(defn increment [] (++ *count*) *count*)

(increment)

(increment)
(increment)

Prologue and Epilogue

Use :prologue or :epilogue to include code before or after the main body of the src block.

(def phi^2 (+ phi 1))

File Output

Use :file and a path to write output (or value) to a file

(loop [i :range [1 11]]
  (print i))

see: file:numbers.txt

Debug

Preview expanded code, without evaluation, by adding :debug to the header. The output is the unevaluated code that would be sent to a Janet process.

(+ x 10)

(+ x 10)

Customization

Customize ob-janet settings with the ob-janet customization group, M-x customize-group ob-janet

Variable	Description	Default
ob-janet-executable	Path to Janet executable	"janet"
ob-janet-hline-to	Replacement for table hlines in Janet	"nil"
ob-janet-nil-to	Replacement for Janet nil in results	'hline
ob-janet-value-wrapper	Template for wrapping value results	see: ob-janet.el
ob-janet-output-wrapper	Template for wrapping output results	see: ob-janet.el

Troubleshooting

Janet not found

Ensure janet is on your PATH, or customize ob-janet-executable to include the full path to the janet executable.

(setq ob-janet-executable "/usr/local/bin/janet")

Modules (or symbols) not found

Modules and libraries are located using the JANET_PATH environment variable. If JANET_PATH is not set, or has been redefined, the variable ob-janet-path can be used to set the correct path.

(setq ob-janet-path "/usr/local/lib/janet/")