Docco is a command line tool that generates HTML documentation from source code files and their comments. It uses Markdown to format comments and Pygments for syntax highlighting of code. Comments and code are displayed side-by-side in the generated HTML. Docco works with languages like CoffeeScript, JavaScript, Ruby, Python and more. It is open source and available on GitHub under the MIT license.

1. docco.coffee
Docco is a quick-and-dirty, hundred-line-long, literate-
programming-style documentation generator. It produces HTML
that displays your comments alongside your code. Comments are
passed through Markdown, and code is passed through Pygments
syntax highlighting. This page is the result of running Docco
against its own source file.
If you install Docco, you can run it from the command-line:
docco src/*.coffee
...will generate linked HTML documentation for the named source
files, saving it into a docs folder.
The source for Docco is available on GitHub, and released under
the MIT license.
To install Docco, first make sure you have Node.js, Pygments
(install the latest dev version of Pygments from its Mercurial
repo), and CoffeeScript. Then, with NPM:
sudo npm install docco
If Node.js doesn't run on your platform, or you'd prefer a more
convenient package, get Rocco, the Ruby port that's available as a
gem. If you're writing shell scripts, try Shocco, a port for the
POSIX shell. Both are by Ryan Tomayko. If Python's more your
speed, take a look at Nick Fitzgerald's Pycco.
Main Documentation Generation Functions
Generate the documentation for a source file by reading it in, generate_documentation = (source, callback) ->
splitting it up into comment/code sections, highlighting them for fs.readFile source, "utf-8", (error, code) ->
throw error if error
the appropriate language, and merging them into an HTML
sections = parse source, code
template. highlight source, sections, ->
generate_html source, sections
callback()
Given a string of source code, parse out each comment and the parse = (source, code) ->
code that follows it, and create an individual section for it. lines = code.split 'n'
sections = []
Sections take the form:
language = get_language source
{ has_code = docs_text = code_text = ''
docs_text: ...
docs_html: ... save = (docs, code) ->
code_text: ... sections.push docs_text: docs, code_text: code
code_html: ...
} for line in lines
if line.match language.comment_matcher
if not (line.match language.comment_filter)
if has_code
save docs_text, code_text
has_code = docs_text = code_text = ''
docs_text += line.replace(language.comment_matcher, '') + 'n'
else
has_code = yes
code_text += line + 'n'
save docs_text, code_text
sections
Highlights a single chunk of CoffeeScript code, using Pygments highlight = (source, sections, callback) ->
over stdio, and runs the text of its corresponding comment language = get_language source
pygments = spawn 'pygmentize', ['-l', language.name, '-f', 'html', '-O', 'enco
through Markdown, using the Github-flavored-Markdown
output = ''
modification of Showdown.js. pygments.stderr.addListener 'data', (error) ->
console.error error if error
We process the entire file in a single call to Pygments by inserting pygments.stdout.addListener 'data', (result) ->
little marker comments between each section and then splitting output += result if result
the result string wherever our markers occur. pygments.addListener 'exit', ->

2. output = output.replace(highlight_start, '').replace(highlight_end, '')
fragments = output.split language.divider_html
for section, i in sections
section.code_html = highlight_start + fragments[i] + highlight_end
section.docs_html = showdown.makeHtml section.docs_text
callback()
pygments.stdin.write((section.code_text for section in sections).join(language
pygments.stdin.end()
Once all of the code is finished highlighting, we can generate the generate_html = (source, sections) ->
HTML file and write out the documentation. Pass the completed title = path.basename source
dest = destination source
sections into the template found in resources/docco.jst
html = docco_template {
title: title, sections: sections, sources: sources, path: path, destination:
}
console.log "docco: #{source} -> #{dest}"
fs.writeFile dest, html
Helpers & Setup
Require our external dependencies, including Showdown.js (the fs = require 'fs'
JavaScript implementation of Markdown). path = require 'path'
showdown = require('./../vendor/showdown').Showdown
{spawn, exec} = require 'child_process'
A list of the languages that Docco supports, mapping the file languages =
extension to the name of the Pygments lexer and the symbol that '.coffee':
name: 'coffee-script', symbol: '#'
indicates a comment. To add another language to Docco's
'.js':
repertoire, add it here. name: 'javascript', symbol: '//'
'.rb':
name: 'ruby', symbol: '#'
'.py':
name: 'python', symbol: '#'
Build out the appropriate matchers and delimiters for each for ext, l of languages
language.
Does the line begin with a comment? l.comment_matcher = new RegExp('^s*' + l.symbol + 's?')
Ignore hashbangs) l.comment_filter = new RegExp('^#![/]')
The dividing token we feed into Pygments, to delimit the l.divider_text = 'n' + l.symbol + 'DIVIDERn'
boundaries between sections.
The mirror of divider_text that we expect Pygments to return. l.divider_html = new RegExp('n*<span class="c1?">' + l.symbol + 'DIVIDER</
We can split on this to recover the original sections. Note: the class
is "c" for Python and "c1" for the other languages
Get the current language we're documenting, based on the get_language = (source) -> languages[path.extname(source)]
extension.
Compute the destination HTML path for an input source file path. destination = (filepath) ->
If the source is lib/example.coffee , the HTML will be at 'docs/' + path.basename(filepath, path.extname(filepath)) + '.html'
docs/example.html
Ensure that the destination directory exists. ensure_directory = (callback) ->
exec 'mkdir -p docs', -> callback()
Micro-templating, originally by John Resig, borrowed by way of template = (str) ->
Underscore.js. new Function 'obj',
'var p=[],print=function(){p.push.apply(p,arguments);};' +
'with(obj){p.push('' +
str.replace(/[rtn]/g, " ")
.replace(/'(?=[^<]*%>)/g,"t")
.split("'").join("'")
.split("t").join("'")
.replace(/<%=(.+?)%>/g, "',$1,'")
.split('<%').join("');")
.split('%>').join("p.push('") +
"');}return p.join('');"

3. Create the template that we will use to generate the Docco HTML docco_template = template fs.readFileSync(__dirname + '/../resources/docco.jst'
page.
The CSS styles we'd like to apply to the documentation. docco_styles = fs.readFileSync(__dirname + '/../resources/resources/docco.css
The start of each Pygments highlight block. highlight_start = '<div class="highlight"><pre>'
The end of each Pygments highlight block. highlight_end = '</pre></div>'
Run the script. For each source file passed in as an argument, sources = process.ARGV.sort()
generate the documentation. if sources.length
ensure_directory ->
fs.writeFile 'docs/resources/docco.css', docco_styles
files = sources.slice(0)
next_file = -> generate_documentation files.shift(), next_file if files.leng
next_file()