# -*- mode: org; -*-
#+AUTHOR: Lucien Cartier-Tilet
#+EMAIL: phundrak@phundrak.fr
#+CREATOR: Lucien Cartier-Tilet
#+LANGUAGE: fr

# ### LaTeX ####################################################################

#+LATEX_CLASS: article
#+LaTeX_CLASS_OPTIONS: [a5paper,twoside]
#+LATEX_HEADER: \usepackage{xltxtra,fontspec,xunicode}
#+LATEX_HEADER: \usepackage[total={11cm,17cm}]{geometry}
#+LATEX_HEADER: \setromanfont{Charis SIL}
#+LATEX_HEADER: \usepackage{xcolor}
#+LATEX_HEADER: \usepackage{hyperref}
#+LATEX_HEADER: \hypersetup{colorlinks=true,linkbordercolor=red,linkcolor=blue,pdfborderstyle={/S/U/W 1}}
#+LATEX_HEADER: \usepackage{multicol}
#+LATEX_HEADER: \usepackage{indentfirst}
#+LATEX_HEADER: \sloppy

# ### HTML #####################################################################

#+HTML_DOCTYPE: html5
#+HTML_HEAD: <link rel="shortcut icon" href="https://cdn.phundrak.fr/img/mahakala-128x128.png" type="img/png" media="screen" />
#+HTML_HEAD: <link rel="shortcut icon" href="https://cdn.phundrak.fr/img/favicon.ico" type="image/x-icon" media="screen" />
#+HTML_HEAD: <meta property="og:image" content="https://cdn.phundrak.fr/img/rich_preview.png" />
#+HTML_HEAD: <meta name="twitter:card" content="summary" />
#+HTML_HEAD: <meta name="twitter:site" content="@phundrak" />
#+HTML_HEAD: <meta name="twitter:creator" content="@phundrak" />

# ### CODE #####################################################################

#+NAME: tree-dot
#+BEGIN_SRC emacs-lisp :noweb yes :exports none :eval yes :cache yes
  (defun declare-node (node-text node-generation)
    "Declares a node in the graphviz source code. The node’s identifier will be
  ~node-generation~, and it will bear the label ~node-text~."
    (concat (number-to-string node-generation)
            "[label=\""
            node-text
            "\"];"))

  (defun make-link (previous-node current-node)
    "This creates a link in the graphviz source code between the two nodes
  bearing ~previous-node~ and ~current-node~ respectively as their node
  identifier."
    (concat (number-to-string previous-node) " -- "
            (number-to-string current-node) ";"))

  (defun tree-to-dot-helper (tree current-generation previous-generation)
    "Helper to ~tree-to-dot~ that translates an Elisp tree with any number of
  children per node to a corresponding graphviz file that can be executed from
  dot.
  Arguments:
  - tree :: tree-to-convert
  - current-generation :: Generation number, incremented when changing from a node
       to another node from the same generation, multiplied by 10 when going from
       a node to one of its children.
  - previous-generation :: generation number from previous named node"
    (cond
     ((null tree) "")
     ((atom (car tree)) ;; '("text" () () ())
      (concat (declare-node (car tree) current-generation)
              (make-link previous-generation current-generation)
              (tree-to-dot-helper (cdr tree)
                                  (+ 1 (* 10 current-generation))
                                  current-generation)))
     ((listp (car tree)) ;; '(() () ())
      (concat (tree-to-dot-helper (car tree) ;; child of current node
                                  current-generation
                                  previous-generation)
              (tree-to-dot-helper (cdr tree)
                                  (+ 1 current-generation)
                                  previous-generation)))))

  (defun tree-to-dot (tree)
    "Returns a graphviz’s dot compatible string representing an Elisp tree"
    (if (null tree) ""
      (concat
       "graph{node[shape=plaintext];graph[bgcolor=\"transparent\"];"
       (declare-node (car tree) 0)
       (tree-to-dot-helper (cdr tree) 1 0)
       "}")))
#+END_SRC

# ### MACROS ###################################################################
#+MACRO: newline @@latex:\hspace{0pt}\\@@ @@html:<br>@@
#+MACRO: newpage @@latex:\newpage@@
#+MACRO: latex-html @@latex:$1@@ @@html:$2@@
#+MACRO: phon @@latex:/$1/@@ @@html:&frasl;$1&frasl;@@
#+MACRO: v @@latex:\rotatebox[origin=c]{270}{$1}@@ @@html:<span class=vertical>$1</span>@@
#+MACRO: begin-largetable @@html:<div class="largetable">@@
#+MACRO: end-largetable @@html:</div>@@
#+OPTIONS: H:4 broken_links:mark email:t ^:{}