(defpackage #:papyrus/README
  (:use #:cl))
(in-package #:papyrus/README)
(named-readtables:in-readtable papyrus:md-syntax)

A literate programming tool for Common Lisp.

Papyrus is the name of a programming style as well as the name of a tool with which to implement it. The author of papyrus developed it to do literate programming in LISP better than WEB, developed by Donald Knuth. WEB and it's derived softwares are used in various programming languages. They require developers compiling with them to obtain the source code. It is required in order to do literate programming in C and Pascal, but isn't in Common Lisp because Common Lisp has the reader macro which changes the source code when the system reads it.

flowchart TB
  subgraph Knuth's system
  WEB -- CTANGLE --> Pascal
  WEB -- CWEAVE --> TeX
  end
  subgraph Our system
  Papyrus -- reader macro --> CommonLisp
  Papyrus --- Markdown
  end

Papyrus makes your markdown executable with the reader macro of Common Lisp. For example, the author wrote this document with Papyrus. You can execute it by running ros run -l papyrus.asd -e '(require :papyrus)' -l README.md -q. How about this? Let's make your project more beautiful and useful!

(princ "Hello, Papyrus!")

Copyright (c) 2019 -- 2024 TANIGUCHI Masaya All Rights Reserved

MIT. See the license texts.

This is a new project. Please send me your feedback if you find any issues.

• Project home

In Papyrus, you can write any text like the following, and make the file extension md. Also, you can write with Markdown, especially CommonMark whose specification can be found at commonmark.org. Papyrus only evaluates codeblocks after (enable-md-syntax) that are enclosed by ```lisp and ```. The indented codeblock before (enable-md-syntax) is important, as this codeblock specifies the required packages. Please do not forget it.

    (defpackage #:tutorial
      (:use #:cl)
      (:export #:hello))
    (in-package #:tutorial)
    (named-readtables:in-readtable papyrus:md-syntax)

# My First Document

This is my first document.
This will say "Hello, world!".

```lisp
(defun hello ()
  (princ "Hello, world!"))
```

If you try this tutorial, save it as tutorial.md, as this is the filename used in this section. Now, there are two ways to generate the document, REPL and ASDF. The following are quick tutorials for each. For more information, please see the Reference section.

A REPL is a good environment to experiment with your Papyrus documents. We can load them and test the behaivor quickly and it is convenient to use them with SLIME.

Papyrus is available in QuickLisp. To install Just type,

> (ql:quickload :papyrus)

Or, you can install Papyrus with Roswell.

$ ros install tani/papyrus

Next you can load document as follows:

> (require :papyrus)
nil
> (load #p"tutorial.md")
nil
> (tutorial:hello)
Hello, World!

Let's write a small project whose files are the following.

tutorial.asd
tutorial.md

tutorial.md is the file written in the REPL section, and tutorial.asd is this:

(defclass md (cl-source-file)
  ((type :initform "md")))

(defclass org (cl-source-file)
  ((type :initform "org")))

(defclass pod (cl-source-file)
  ((type :initform "pod")))

(defsystem tutorial
  :version "0.1"
  :author "Your name"
  :license "MIT"
  :depends-on (#:papyrus #:named-readtables)
  :components ((:md "tutorial"))
  :description "A Literate Programming Framework")

Now that you have both files, tutorial.md and tutorial.asd, you will be able to load this system like this.

> (load #p"tutorial.asd")
nil
> (require :tutorial)
nil
> (tutorial:hello)
Hello, World!

Of course, users of your project won't need to load anything else.

This is a readtable defined for Markdown. The codeblock enclosed by ```lisp and ``` is evaluated.

    (defpackage #:sample
      (:use #:cl)
      (:export #:sample-function))
    (in-package #:sample)
    (named-readtables:in-readtable papyrus:md-syntax)

# Sample

This is a sample code. The following function just says "Hello, world!"

```lisp
(defun sample-function () (princ "Hello, world!"))
```

This is a readtable for org-mode. The codeblock enclosed by #+BEGIN_SRC lisp :tangle yes and #+END_SRC is evaluated. Unlike Markdown, any #+CL: tags are ignored when rendering the content to HTML.

#+CL:* * (defpackage #:sample
#+CL:* *   (:use #:cl)
#+CL:* *   (:export #:sample-function))
#+CL:* * (in-package #:sample)
#+CL:* * (named-readtables:in-readtable papyrus:org-syntax)

This is a sample code. The following function just says "Hello, world!"

#+BEGIN_SRC lisp :tangle yes
(defun sample-function () (princ "Hello, world!"))
#+END_SRC

This is a readtable defined by named-readtables for POD. The codeblock outside of =pod and =cut is evaluated. This syntax is similar to Perl's POD.

(defpackage #:sample
  (:use #:cl)
  (:export #:sample-function))
(in-package #:sample)
(named-readtables:in-readtable papyrus:pod-syntax)

=pod

This is a sample code. The following function just says "Hello, world!"

=cut

(defun sample-function () (princ "Hello, world!"))

Try to use polymode

(require 'poly-markdown)
(add-to-list 'auto-mode-alist '("\\.md" . poly-markdown-mode))

If you use emacs, there is mmm-mode which highlights the syntax of lisp codeblocks in Markdown, but SLIME doesn't works well in mmm-mode.

(require 'mmm-mode)
(setq mmm-global-mode 'maybe)
(set-face-background 'mmm-default-submode-face nil)
(mmm-add-mode-ext-class nil "\\.md?\\'" 'lisp-markdown)
(mmm-add-classes
 '((lisp-markdown
    :submode lisp-mode
    :front "```lisp"
    :back "```")))