#! /usr/bin/env retro

RETRO programs are written using a literate format called Unu which allows mixing of code and commentary in a somewhat literate format.

Code (and optionally tests) is extracted from fenced blocks, and commentary normally uses a subset of Markdown.

This tool processes both parts, generating formatted HTML documents that look nice, and also provides syntax highlighting for the test and code blocks.

Features

For Markdown:

• lists
• indented code blocks
• paragraphs
• headers
• fenced code and test blocks
• horizontal rules
• inline formatting elements

For RETRO:

• syntax highlighting of most elements
• uses introspection to identify primitives

For both:

• easily customizable via CSS at the end of this file

Limitations

This only supports a limited subset of full Markdown. I am not adding support for the various linking formats, ordered lists, underlined headers, doubled asterisk, doubled underscores, multiple line/paragraph list entries, or images.

The formatting must follow the following limits:

# Title ## Subtitle ### Level 3 Title Paragraph. *Bold*, _italics_, `inline code`. Another paragraph. - list element - list element   - nested list element   - nested list element - list element ~~~ :retro (code ; ~~~ ``` tests ``` Sample code or output with four leading spaces is note colorized.     this will be code, but not run through the     colorizer. More paragraph text. ---- Above is a horizontal separator.

This is not very intelligent. If you have text like 3 * 4, it'll happily treat the * as the start of a bold sequence. Use a leading backslash to avoid this.

HTML is pretty verbose and wants a bunch of boilerplate to work nicely, so I start with some header stuff.

~~~'<html><head> s:put nl ~~~

Locate and embed the CSS from the end of this file.

~~~'<style> s:put nl FALSE script:name   [ over [ '##_CSS s:eq? or ] -if; s:put nl ] file:for-each-line drop '</style> s:put nl ~~~

Finish the header boilerplate text and switch to the body.

~~~'</head><body> s:put nl ~~~

The first couple of words are a variation of s:put that generates HTML codes for specific characters. This ensures that code output displays correctly.

~~~:c:put<code>   $< [ '&lt; s:put ] case   $> [ '&gt; s:put ] case   $& [ '&amp; s:put ] case   ASCII:SPACE [ '&nbsp; s:put ] case   c:put ;   :s:put<code> [ c:put<code> ] s:for-each ; ~~~

For regular text, there are a couple of inline formatting things to deal with.

~~~'Emphasis var 'Strong var 'Escape var 'Code var   :format   $` [ @Escape [ &Escape v:off $* c:put ] if;        @Code n:zero? [ '<tt_style='display:inline'> &Code v:on ]                      [ '</tt> &Code v:off ] choose s:put ] case   $* [ @Escape @Code or [ &Escape v:off $* c:put ] if;        @Strong n:zero? [ '<strong> &Strong v:on ]                        [ '</strong> &Strong v:off ] choose s:put ] case   $_ [ @Escape @Code or [ &Escape v:off $_ c:put ] if;        @Emphasis n:zero? [ '<em> &Emphasis v:on ]                          [ '</em> &Emphasis v:off ] choose s:put ] case   $\ [ &Escape v:on ] case   c:put ;   :s:put<formatted> [ format ] s:for-each ; ~~~

Code and Test Blocks

The biggest element is the code and test blocks.

These will be generated in an enclosure that looks like:

<div class='codeblock'><tt> ... code ... </tt></div>

The actual words in the code will be in elements.

The fences need to start and end with ~~~ or three backticks on a line by itself.

So, identifying and generating an HTML container for a code block is a matter of:

~~~{{   'Block var   :begin   '<div_class='codeblock'><tt>~~~</tt> ;   :end     '<tt>~~~</tt></div> ; ---reveal---   :in-code-block? (-f)   @Block ;   :code-block?    (s-sf) dup '~~~ s:eq? ;   :toggle-code (n-)     drop @Block n:zero? dup &begin &end choose s:put !Block ; }} ~~~

And test blocks are basically the same, except for the delimiters.

~~~{{   'Block var   :begin   '<div_class='codeblock'><tt>```</tt> ;   :end     '<tt>```</tt></div> ; ---reveal---   :in-test-block? (-f)   @Block ;   :test-block?    (s-sf) dup '``` s:eq? ;   :toggle-test (n-)     drop @Block n:zero? dup &begin &end choose s:put !Block ; }} ~~~

On to generating the actual HTML for the syntax highlighted source. This is driven by the sigil, then by word class via a little quick introspection.

~~~{{   :span (s-)     '<span_class=' s:put s:put ''> s:put s:put<code> '</span>_ s:put ; ---reveal---   :format-code (s-)     (ignore_empty_tokens)     dup s:length n:zero? [ '&nbsp; s:put drop ] if;       (tokens_with_sigils)     dup fetch     $: [ 'colon     span ] case     $( [ 'note      span ] case     $' [ 'str       span ] case     $# [ 'num       span ] case     $. [ 'fnum      span ] case     $& [ 'ptr       span ] case     $$ [ 'char      span ] case     $` [ 'inst      span ] case     $\ [ 'inst      span ] case     $| [ 'defer     span ] case     $@ [ 'fetch     span ] case     $! [ 'store     span ] case        (immediate_and_primitives)     drop dup     d:lookup d:class fetch     &class:macro     [ 'imm  span ] case     &class:primitive [ 'prim span ] case     drop        (normal_words)     s:put<code> sp ;     :colorize      ASCII:SPACE s:tokenize &format-code a:for-each ;     :format:code     '<tt> s:put colorize '</tt> s:put nl ; }} ~~~

Headers

After this, I define detection and formatting of headers. The headers should look like:

# Level 1 ## Level 2 ### Level 3

~~~:header?   dup [ '#_ s:begins-with?   ]       [ '##_ s:begins-with?  ]       [ '###_ s:begins-with? ] tri or or   over '####_ s:begins-with? or ;   :format:head   ASCII:SPACE s:split/char   '#   [ '<h1> s:put n:inc s:put '</h1> s:put nl ] s:case   '##  [ '<h2> s:put n:inc s:put '</h2> s:put nl ] s:case   '### [ '<h3> s:put n:inc s:put '</h3> s:put nl ] s:case   '#### [ '<h4> s:put n:inc s:put '</h4> s:put nl ] s:case   drop ; ~~~

Indented Code Blocks

Indented code blocks are lines indented by four spaces. These are not syntax highlighted as they are ignored by Unu.

~~~:inline-code? dup '____ s:begins-with? ; :format:inline-code   '<tt_class='indentedcode'> s:put   #4 + s:put<code>   '</tt> s:put nl ; ~~~

Horizontal Rules

Horizonal rules consist of four or more - characters on a line. E.g.,

---- --------

This also accepts sequences of -+-+ which were used in some older RETRO source files.

~~~:rule?   dup [ '---- s:begins-with? ] [ '-+-+ s:begins-with? ] bi or ; :format:rule drop '<hr> s:put nl ; ~~~

Lists

Lists start with a - or *, followed by a space, then the item text. Additionally, this allows for nested lists starting with two spaces before the list marker.

~~~:list?   dup [ '-_ s:begins-with? ] [ '*_ s:begins-with? ] bi or ; :format:list '&bull;_ s:put #2 + s:put<formatted> '<br> s:put nl ;   :indented-list?   dup [ '__-_ s:begins-with? ] [ '__*_ s:begins-with? ] bi or ; :format:indented-list   '<span_class='indentedlist'>&bull; s:put   #3 + s:put<formatted> '</span><br> s:put nl ; ~~~

Paragraphs

Blank lines denote paragraph breaks.

~~~:blank? dup s:length n:zero? ; ~~~

The Formatter

This ties together the various words above, generating the output.

~~~:format   s:keep   code-block?    [ toggle-code ] if;   in-code-block? [ format:code ] if;   test-block?    [ toggle-test ] if;   in-test-block? [ format:code ] if;   blank?         [ drop '<p> s:put nl ] if;   header?        [ format:head ] if;   inline-code?   [ format:inline-code ] if;   list?          [ format:list ] if;     indented-list? [ format:indented-list ] if;   rule?          [ format:rule ] if;   s:put<formatted> nl ;   #0 script:get-argument [ &Heap &format v:preserve ] file:for-each-line reset ~~~

This concludes the Markdown (subset) in RETRO utility. All that's left is the CSS.

For the colors, I'm mostly using the Tomorrow Night colors as listed at https://github.com/chriskempson/tomorrow-theme

CSS

* {   color: #cccccc;   background: #2d2d2d;   max-width: 700px; } tt, pre {   background: #1d1f21; color: #b5bd68; font-family: monospace;    white-space: pre;   display: block;   width: 100%; } .indentedcode {   margin-left: 2em;   margin-right: 2em; } .codeblock {   background: #1d1f21; color: #b5bd68; font-family: monospace;    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);   padding: 7px; } .indentedlist {   margin-left: 2em;   color: #cccccc;   background: #2d2d2d; } span { white-space: pre; background: #1d1f21; } .text  { color: #c5c8c6; white-space: pre } .colon { color: #cc6666; } .note  { color: #969896; } .str   { color: #f0c674; } .num   { color: #8abeb7; } .fnum  { color: #8abeb7; font-weight: bold; } .ptr   { color: #b294bb; font-weight: bold; } .fetch { color: #b294bb; } .store { color: #b294bb; } .char  { color: #81a2be; } .inst  { color: #de935f; } .defer { color: #888888; } .imm   { color: #de935f; } .prim  { color: #b5bd68; font-weight: bold; }