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diff --git a/content/emacs/org-babel.md b/content/emacs/org-babel.md deleted file mode 100644 index 691f6c7..0000000 --- a/content/emacs/org-babel.md +++ /dev/null @@ -1,175 +0,0 @@ -+++ -title = "Emacs: Executing code in Org files with Babel" -author = ["Michał Sapka"] -date = 2024-02-07T21:23:00+01:00 -categories = ["emacs"] -draft = false -weight = 2003 -abstract = "A short introduction into the world if Org Babel" -[menu] - [menu.emacs] - weight = 2003 - identifier = "emacs-executing-code-in-org-files-with-babel" - parent = "litprog" - name = "Literate programing in Org with Babel" -+++ - -**Abstract**: a very short introduction into the word of Org Babel. - -No other package seems to have had such huge impact on Emacs community as the introduction of Org Babel[^fn:1]. -It made folks not only love their Org Mode, but _live_ in it. - -In short: Babel allows for [literate programming](/emacs/literate-programing-in-emacs/) form within an Org document. - - -## Source code basics {#source-code-basics} - -Babel comes baked into any modern version of `Emacs`, so you've already got everything you need. -Open any `org` document, add the code to the document within source code blocks: - -```emacs-lisp -regular text - -#+BEGIN_SRC emacs-lisp -(+ 1 1) -#+END_SRC - -and more regular text -``` - -Now, move the pointer to with the blocks, tap `C-c C-c` and the code is evaluated. -The result will be appended just below the source code, in a `RESULT` block. - -You now know how to do literate programming in Emacs. -Create an Org document, add your narrative, add your source code and execute. -Simple, isn't it? - -By default, `Babel` allows only for execution of `emacs-lisp` mode, but it supports many more. -You can enable all supported via: - -```emacs-lisp -(org-babel-do-load-languages 'org-babel-load-languages - '((shell . t) - (js . t) - (emacs-lisp . t) - (clojure . t) - (python . t) - (ruby . t) - (dot . t) - (css . t) - (plantuml . t))) -``` - -There are even more provided as dedicated packages. - - -## Being faster {#being-faster} - -Typing `#+BEGIN_SRC` can become tedious pretty quick. -We can use the `org-tempo` package to make it much faster. - -```emacs-lisp -(require 'org-tempo) -(setq org-structure-template-alist - '(("s" . "src"))) -``` - -Now, we can create new block simply by taping `<s` and pressing tab. - -Org tempo supports many more blocks, you can refer to [the official manual](https://orgmode.org/manual/Structure-Templates.html). - - -## Joining the blocks together {#joining-the-blocks-together} - -In _strict_ Literate Programming sense, your _web/_ should not be where you execute code. -Instead, you should extract programmatic parts and run it separately - the process is called _tangling_. - -Babel bypasses this limitation with `noweb` mode, in which code blocks can reference each other. -First, you need to name your code blocks: - -```emacs-lisp -#+NAME: two -#+BEGIN_SRC emacs-lisp -(+ 1 1) -#+END_SRC -``` - -Then we can use it the result other code blocks - -```emacs-lisp -#+NAME: three -#+BEGIN_SRC emacs-lisp :noweb yes -(+ <<two>> 1) -#+END_SRC -``` - -Here, the `<<two>>` will be replaced with the result of block named `two`. -This makes the block `three` return the number `3`. - -This mode gives quite a lot more option. -You can read about them inside [manual](https://orgmode.org/manual/Noweb-Reference-Syntax.html). - - -## Running on remote machines {#running-on-remote-machines} - -To make it even _cooler_, Babel integrates with `Tramp` mode which allows for execution over ssh! -You can add a tramp-style header argument as `:dir` and the code will be executed over the established connection. - -```emacs-lisp -#+BEGIN_SRC shell :dir /user@host:~/ -rm -rf / -#+END_SRC -``` - -And boom - we've got a bomb. - - -## Babel as source for Emacs configuration {#babel-as-source-for-emacs-configuration} - -The most popular use case of Babel however is Emacs configuration. -You can have as many org files as you want, have the configuration inside `emacs-lisp` code blocks and use that as config. - - -### Loading files directly {#loading-files-directly} - -If your config isn't _very_ complicated, you can force Emacs to parse the files on boot. -To achieve that, add - -```emacs-lisp -(org-babel-load-file "~/.emacs.d/config.org") -``` - -To your `init.el`. - -What happens is, that Emacs will create a corresponding `config.el` (_tangle_) file and load it as a elisp file. -Just remember not to name your config as `init.org` as there will be naming conflict with `init.el`. - - -### Pre-tangling {#pre-tangling} - -If you don't want _tangling_ on boot time, but rather want to have it ready you can manually _org-babel-tangle_. -To achieve it, add a `tangle` header argument to all you code blocks: - -```emacs-lisp -#+BEGIN_SRC emacs-lisp :tangle ~/.emacs.d/init.el -(+ 1 1) -#+END_SRC -``` - -And then, after any changes of the file run `org-babel-tangle` and your `init.el` will be up-to-date. -This is the approach [Prot](https://protesilaos.com/codelog/2023-12-18-emacs-org-advanced-literate-conf/) uses, but his config consists of over _17_000_ [sic!] lines of org file, so your mileage may vary. - - -## Links {#links} - -If you are interested in the subject, you can look at much more details sources: - -- [Official website](https://orgmode.org/worg/org-contrib/babel/intro.html) -- [Literate devops](https://howardism.org/Technical/Emacs/literate-devops.html) on Howardism -- [Advanced literate configuration](https://protesilaos.com/codelog/2023-12-18-emacs-org-advanced-literate-conf/) on Prot's website. -- [Cheat sheet](https://org-babel.readthedocs.io/en/latest/) - -[^fn:1]: you may argue and say that `magit` had bigger impact. - I disagree. - Magit made using git nicer and easier, but it is still the old, old git. - Babel changed the way we use the edit code, the way we think and how we work. |