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, splitting it
up into comment/code sections, highlighting them for the appropriate language,
and merging them into an HTML template.
             		                            
generate_documentation = (source, callback) ->
  fs.readFile source, "utf-8", (error, code) ->
    throw error if error
    sections = parse source, code
    highlight source, sections, ->
      generate_html source, sections
      callback()
             		           
                               
                            
                                
               
Given a string of source code, parse out each comment and the code that
follows it, and create an individual section for it.
Sections take the form:



{
  docs_text: ...
  docs_html: ...
  code_text: ...
  code_html: ...
}

             		                            
parse = (source, code) ->
  lines    = code.split '\n'
  sections = []
  language = get_language source
  has_code = docs_text = code_text = ''

  save = (docs, code) ->
    sections.push docs_text: docs, code_text: code

  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 over stdio,
and runs the text of its corresponding comment through Markdown, using the
Github-flavored-Markdown modification of Showdown.js.



We process the entire file in a single call to Pygments by inserting little
marker comments between each section and then splitting the result string
wherever our markers occur.
             		                            
highlight = (source, sections, callback) ->
  language = get_language source
  pygments = spawn 'pygmentize', ['-l', language.name, '-f', 'html', '-O', 'encoding=utf-8']
  output   = ''
  pygments.stderr.addListener 'data',  (error)  ->
    console.error error if error
  pygments.stdout.addListener 'data', (result) ->
    output += result if result
  pygments.addListener 'exit', ->
    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.divider_text))
  pygments.stdin.end()
             		           
                               
                            
                                
               
Once all of the code is finished highlighting, we can generate the HTML file
and write out the documentation. Pass the completed sections into the template
found in resources/docco.jst
             		                            
generate_html = (source, sections) ->
  title = path.basename source
  dest  = destination source
  html  = docco_template {
    title: title, sections: sections, sources: sources, path: path, destination: destination
  }
  console.log "docco: #{source} -> #{dest}"
  fs.writeFile dest, html
             		           
                               
                            
                                
               
Helpers & Setup
             		                            
             		           
                               
                            
                                
               
Require our external dependencies, including Showdown.js
(the JavaScript implementation of Markdown).
             		                            
fs       = require 'fs'
path     = require 'path'
showdown = require('./../vendor/showdown').Showdown
{spawn, exec} = require 'child_process'
             		           
                               
                            
                                
               
A list of the languages that Docco supports, mapping the file extension to
the name of the Pygments lexer and the symbol that indicates a comment. To
add another language to Docco's repertoire, add it here.
             		                            
languages =
  '.coffee':
    name: 'coffee-script', symbol: '#'
  '.js':
    name: 'javascript', symbol: '//'
  '.rb':
    name: 'ruby', symbol: '#'
  '.py':
    name: 'python', symbol: '#'
             		           
                               
                            
                                
               
Build out the appropriate matchers and delimiters for each language.
             		                            
for ext, l of languages
             		           
                               
                            
                                
               
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 boundaries between
sections.
             		                            
  l.divider_text = '\n' + l.symbol + 'DIVIDER\n'
             		           
                               
                            
                                
               
The mirror of divider_text that we expect Pygments to return. We can split
on this to recover the original sections.
Note: the class is "c" for Python and "c1" for the other languages
             		                            
  l.divider_html = new RegExp('\\n*<span class="c1?">' + l.symbol + 'DIVIDER<\\/span>\\n*')
             		           
                               
                            
                                
               
Get the current language we're documenting, based on the extension.
             		                            
get_language = (source) -> languages[path.extname(source)]
             		           
                               
                            
                                
               
Compute the destination HTML path for an input source file path. If the source
is lib/example.coffee, the HTML will be at docs/example.html
             		                            
destination = (filepath) ->
  'docs/' + path.basename(filepath, path.extname(filepath)) + '.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
Underscore.js.
             		                            
template = (str) ->
  new Function 'obj',
    'var p=[],print=function(){p.push.apply(p,arguments);};' +
    'with(obj){p.push(\'' +
    str.replace(/[\r\t\n]/g, " ")
       .replace(/'(?=[^<]*%>)/g,"\t")
       .split("'").join("\\'")
       .split("\t").join("'")
       .replace(/<%=(.+?)%>/g, "',$1,'")
       .split('<%').join("');")
       .split('%>').join("p.push('") +
       "');}return p.join('');"
             		           
                               
                            
                                
               
Create the template that we will use to generate the Docco HTML page.
             		                            
docco_template  = template fs.readFileSync(__dirname + '/../resources/docco.jst').toString()
             		           
                               
                            
                                
               
The CSS styles we'd like to apply to the documentation.
             		                            
docco_styles    = fs.readFileSync(__dirname + '/../resources/resources/docco.css').toString()
             		           
                               
                            
                                
               
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, generate the documentation.
             		                            
sources = process.ARGV.sort()
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.length
    next_file()