#+TITLE: Terminal
#+AUTHOR: Christopher James Hayward
#+EMAIL: chris@chrishayward.xyz

#+PROPERTY: header-args:emacs-lisp :tangle terminal.el :comments org
#+PROPERTY: header-args            :results silent :eval no-export :comments org

#+OPTIONS: num:nil toc:nil todo:nil tasks:nil tags:nil
#+OPTIONS: skip:nil author:nil email:nil creator:nil timestamp:nil

Performing terminal interactions is a must-have for any modern editor. This module introduces *two* means of doing so with [[https://gnu.org/software/emacs/manual/html_node/eshell/index.html][EShell]][fn:1] and [[https://github.com/akermu/emacs-libvterm][VTerm]][fn:2].

* Emacs Lisp shell

*EShell*[fn:1] is a fully *POSIX* compliant shell written entirely in Emacs Lisp. While not a traditional terminal emulator, it provides a native REPL for Emacs Lisp code with everything available in the environment.

+ Don't highlight the prompt
+ Favour use of system utilities
+ Open in the current buffer with =SPC e=

#+begin_src emacs-lisp
(setq eshell-highlight-prompt nil
      eshell-prefer-lisp-functions nil)

(dotfiles/leader "e" '(eshell :which-key "Shell"))
#+end_src

** Prompt extras

Implement the lambda prompt for aesthetic purposes with the [[https://github.com/zwild/eshell-prompt-extras][EShell Prompt Extras]][fn:3] package.

#+begin_src emacs-lisp
(use-package eshell-prompt-extras
  :custom (eshell-prompt-function 'epe-theme-lambda))
#+end_src

Here's an example of what that looks like:

#+begin_example
~/.emacs.d/modules:main*? λ 
#+end_example

* Interactive Terminal

*EShell*[fn:1] isn't enough when needing interactivity from the terminal. Going through [[file:../docs/notes/thinking-in-cpp.org.gpg][Thinking in C++]][fn:4] for one of my courses required lots of terminal interaction which *Eshell*[fn:1] was unable to handle. *VTerm's*[fn:2] based on an external C library which is blazing fast, and fully interactive.

+ Always compile the module
+ Open in the current buffer with =SPC v=
+ Install the required packages on *Debian/Ubuntu*

#+begin_src emacs-lisp
(use-package vterm
  :commands (vterm)
  :custom (vterm-always-compile-module t)
  :config (dotfiles/leader "v" '(vterm-other-window :which-key "Terminal")))
#+end_src

* Footnotes

[fn:1] https://gnu.org/software/emacs/manual/html_node/eshell/index.html

[fn:2] https://github.com/akermu/emacs-libvterm

[fn:3] https://github.com/zwild/eshell-prompt-extras

[fn:4] https://chrishayward.xyz/posts/immutable-emacs/