#* 

Markdown Underlined Headings and table of contents
============================

  This is a slightly modified version of markdown.underline.pss
  that also creates a table of contents at the top of the document
  using the "mark" and "go" commands.

  Attempting to recognise markdown style heading and format them as html.  
  empty lines are lost. As usual it seems very verbose for a
  script that doesnt do very much.

Notes
-----

Testing 
-------

  try: pp -f markdown.underline.pss markdown.underline.pss

History
=======

  13 March 2020
    Began to code this script in a desultory fashion.
    
*#

begin {
  # label the top tape cell and make room for it.
  mark "top"; add "toc*"; push;  
}

read;

"\n" { clear; }
until "\n"; E"\n" { clip; } put; 
# if the underlines have a space at the end this will fail
[= ].E"==" {
  clear; add "double.uline*"; push; .reparse 
} 
[- ].E"--" {
  clear; add "single.uline*"; push; .reparse 
} 
clear; add "line*"; push; .reparse 

parse>

  # 2 tokens
  pop; pop;
  "line*double.uline*" { 
    clear; 
    add "<li class='level2'>"; get; add "</li>\n"; 
    mark "here"; go "top"; 
    swap; get; put; go "here"; clear; 
    add "<h2>"; get; add "</h2>"; add "\n"; put; clear;
    add "line*"; push; .reparse
  }
  "line*single.uline*" { 
    clear; 
    add "<li class='level3'>"; get; add "</li>\n"; 
    mark "here"; go "top"; 
    swap; get; put; go "here"; clear; 
    add "<h3>"; get; add "</h3>"; add "\n"; put; clear;
    add "line*"; push; .reparse
  }

  <eof> {
    "*line*line", "lines*line*" { 
      clear; get; add "\n"; ++; get; --; add "\n"; put; clear; 
      add "lines*"; push; .reparse
    }
  }

  # 3 tokens
  pop;
  # we use 3 tokens as a kind of look-ahead 
  "line*line*line*", "lines*line*line*" { 
    clear; get; add "\n"; ++; get; --; put; clear; 
    ++; ++; get; --; put; --; clear;
    add "lines*line*"; push; push; .reparse
  }

  # did the script parse properly
  <eof> {
    "toc*lines*" {
      clear; add "<ul>\n"; get; add "</ul>\n"; 
      ++; get; print; clear; quit;
    }
  }

  push; push; push;