#!/bin/sh
":"; exec emacs --no-site-file --script "$0" -- "$@" # -*-emacs-lisp-*-

;; Extracts source blocks from org files and prints them to stdout. Debug/info
;; messages are directed to stderr and can be ignored. -l/--lang can be used to
;; only tangle blocks of a certain language.
;;
;; Usage: org-tangle [[-l|--lang] LANG] some-file.org another.org
;; Examples:
;;   org-tangle modules/ui/doom/README.org > install_fira_mono.sh
;;   org-tangle -l sh modules/lang/go/README.org | sh

(load "~/.emacs.d/core/core.el" nil t)

(require 'org-install)
(require 'org)
(require 'ob-tangle)

(defun *org-babel-tangle (orig-fn &rest args)
  "Don't write tangled blocks to files, print them to stdout."
  (cl-letf (((symbol-function 'write-region)
             (lambda (start end filename &optional append visit lockname mustbenew)
               (princ (buffer-string)))))
    (apply orig-fn args)))
(advice-add #'org-babel-tangle :around #'*org-babel-tangle)

(let ((lang (when (member (car command-line-args-left) '("--lang" "-l"))
              (pop command-line-args-left)
              (pop command-line-args-left)))
      (srcs (cl-remove-if-not 'file-exists-p command-line-args-left)))
  (dolist (file srcs)
    (org-babel-tangle-file file nil lang)))