rocco/lib/rocco.rb
Mike West 020e8050bc Autopopulate comment_chars for known languages
Adding comment characters for bash, c, c++, coffee script, java, javascript, lua, python, ruby, and scheme.  Paving the way for block-comment parsing later on...

Closes issue #20.
2010-10-20 17:07:14 +02:00

324 lines
12 KiB
Ruby

# **Rocco** is a Ruby port of [Docco][do], the quick-and-dirty,
# hundred-line-long, literate-programming-style documentation generator.
#
# Rocco reads Ruby source files and produces annotated source documentation
# in HTML format. Comments are formatted with [Markdown][md] and presented
# alongside syntax highlighted code so as to give an annotation effect.
# This page is the result of running Rocco against [its own source file][so].
#
# Most of this was written while waiting for [node.js][no] to build (so I
# could use Docco!). Docco's gorgeous HTML and CSS are taken verbatim.
# The main difference is that Rocco is written in Ruby instead of
# [CoffeeScript][co] and may be a bit easier to obtain and install in
# existing Ruby environments or where node doesn't run yet.
#
# Install Rocco with Rubygems:
#
# gem install rocco
#
# Once installed, the `rocco` command can be used to generate documentation
# for a set of Ruby source files:
#
# rocco lib/*.rb
#
# The HTML files are written to the current working directory.
#
# [no]: http://nodejs.org/
# [do]: http://jashkenas.github.com/docco/
# [co]: http://coffeescript.org/
# [md]: http://daringfireball.net/projects/markdown/
# [so]: http://github.com/rtomayko/rocco/blob/master/lib/rocco.rb#commit
#### Prerequisites
# We'll need a Markdown library. [RDiscount][rd], if we're lucky. Otherwise,
# issue a warning and fall back on using BlueCloth.
#
# [rd]: http://github.com/rtomayko/rdiscount
begin
require 'rdiscount'
rescue LoadError => boom
warn "WARNING: #{boom}. Trying bluecloth."
require 'bluecloth'
Markdown = BlueCloth
end
# We use [{{ mustache }}](http://defunkt.github.com/mustache/) for
# HTML templating.
require 'mustache'
# We use `Net::HTTP` to highlight code via <http://pygments.appspot.com>
require 'net/http'
# Code is run through [Pygments](http://pygments.org/) for syntax
# highlighting. If it's not installed, locally, use a webservice.
include FileTest
if !ENV['PATH'].split(':').any? { |dir| executable?("#{dir}/pygmentize") }
warn "WARNING: Pygments not found. Using webservice."
end
#### Public Interface
# `Rocco.new` takes a source `filename`, an optional list of source filenames
# for other documentation sources, an `options` hash, and an optional `block`.
# The `options` hash respects three members:
#
# * `:language`: specifies which Pygments lexer to use if one can't be
# auto-detected from the filename. _Defaults to `ruby`_.
#
# * `:comment_chars`, which specifies the comment characters of the
# target language. _Defaults to `#`_.
#
# * `:template_file`, which specifies a external template file to use
# when rendering the final, highlighted file via Mustache. _Defaults
# to `nil` (that is, Mustache will use `./lib/rocco/layout.mustache`)_.
#
class Rocco
VERSION = '0.5'
def initialize(filename, sources=[], options={}, &block)
@file = filename
@sources = sources
# When `block` is given, it must read the contents of the file using
# whatever means necessary and return it as a string. With no `block`,
# the file is read to retrieve data.
@data =
if block_given?
yield
else
File.read(filename)
end
defaults = {
:language => 'ruby',
:comment_chars => '#',
:template_file => nil
}
@options = defaults.merge(options)
@template_file = @options[:template_file]
# If we detect a language
if detect_language() != "text"
# then assign the detected language to `:language`
@options[:language] = detect_language()
# and look for some comment characters
@options[:comment_chars] = generate_comment_chars()
# If we didn't detect a language, but the user provided one, use it
# to look around for comment characters to override the default.
elsif @options[:language] != defaults[:language]
@options[:comment_chars] = generate_comment_chars()
end
@comment_pattern = Regexp.new("^\\s*#{@options[:comment_chars]}\s?")
@sections = highlight(split(parse(@data)))
end
# Returns `true` if `pygmentize` is available locally, `false` otherwise.
def pygmentize?
# Memoize the result, we'll call this a few times
@_pygmentize ||= ENV['PATH'].split(':').any? { |dir| executable?("#{dir}/pygmentize") }
end
# If `pygmentize` is available, we can use it to autodetect a file's
# language based on its filename. Filenames without extensions, or with
# extensions that `pygmentize` doesn't understand will return `text`.
# We'll also return `text` if `pygmentize` isn't available.
#
# We'll memoize the result, as we'll call this a few times.
def detect_language
@_language ||= begin
if pygmentize?
lang = %x[pygmentize -N #{@file}].strip!
else
"text"
end
end
end
# Given a file's language, we should be able to autopopulate the
# `comment_chars` variables for single-line comments. If we don't
# have comment characters on record for a given language, we'll
# use the user-provided `:comment_char` option (which defaults to
# `#`).
#
# Comment characters are listed as:
#
# { :single => "//", :multi_start => "/**", :multi_middle => "*", :multi_end => "*/" }
#
# `:single` denotes the leading character of a single-line comment.
# `:multi_start` denotes the string that should appear alone on a
# line of code to begin a block of documentation. `:multi_middle`
# denotes the leading character of block comment content, and
# `:multi_end` is the string that ought appear alone on a line to
# close a block of documentation. That is:
#
# /** [:multi][:start]
# * [:multi][:middle]
# * [:multi][:middle]
# * [:multi][:middle]
# */ [:multi][:end]
#
# If a language only has one type of comment, the missing type
# should be assigned `nil`.
#
# At the moment, we're only returning `:single`. Consider this
# groundwork for block comment parsing.
def generate_comment_chars
@_commentchar ||= begin
language = @options[:language]
comment_styles = {
"bash" => { :single => "#", :multi => nil },
"c" => { :single => "//", :multi => { :start => "/**", :middle => "*", :end => "*/" } },
"coffee-script" => { :single => "#", :multi => { :start => "###", :middle => nil, :end => "###" } },
"cpp" => { :single => "//", :multi => { :start => "/**", :middle => "*", :end => "*/" } },
"java" => { :single => "//", :multi => { :start => "/**", :middle => "*", :end => "*/" } },
"js" => { :single => "//", :multi => { :start => "/**", :middle => "*", :end => "*/" } },
"lua" => { :single => "--", :multi => nil },
"python" => { :single => "#", :multi => { :start => '"""', :middle => nil, :end => '"""' } },
"ruby" => { :single => "#", :multi => nil },
"scheme" => { :single => ";;", :multi => nil },
}
if comment_styles[language]
comment_styles[language][:single]
else
@options[:comment_chars]
end
end
end
# The filename as given to `Rocco.new`.
attr_reader :file
# The merged options array
attr_reader :options
# A list of two-tuples representing each *section* of the source file. Each
# item in the list has the form: `[docs_html, code_html]`, where both
# elements are strings containing the documentation and source code HTML,
# respectively.
attr_reader :sections
# A list of all source filenames included in the documentation set. Useful
# for building an index of other files.
attr_reader :sources
# An absolute path to a file that ought be used as a template for the
# HTML-rendered documentation.
attr_reader :template_file
# Generate HTML output for the entire document.
require 'rocco/layout'
def to_html
Rocco::Layout.new(self, @template_file).render
end
#### Internal Parsing and Highlighting
# Parse the raw file data into a list of two-tuples. Each tuple has the
# form `[docs, code]` where both elements are arrays containing the
# raw lines parsed from the input file. The first line is ignored if it
# is a shebang line.
def parse(data)
sections = []
docs, code = [], []
lines = data.split("\n")
lines.shift if lines[0] =~ /^\#\!/
lines.each do |line|
case line
when @comment_pattern
if code.any?
sections << [docs, code]
docs, code = [], []
end
docs << line
else
code << line
end
end
sections << [docs, code] if docs.any? || code.any?
sections
end
# Take the list of paired *sections* two-tuples and split into two
# separate lists: one holding the comments with leaders removed and
# one with the code blocks.
def split(sections)
docs_blocks, code_blocks = [], []
sections.each do |docs,code|
docs_blocks << docs.map { |line| line.sub(@comment_pattern, '') }.join("\n")
code_blocks << code.map do |line|
tabs = line.match(/^(\t+)/)
tabs ? line.sub(/^\t+/, ' ' * tabs.captures[0].length) : line
end.join("\n")
end
[docs_blocks, code_blocks]
end
# Take the result of `split` and apply Markdown formatting to comments and
# syntax highlighting to source code.
def highlight(blocks)
docs_blocks, code_blocks = blocks
# Combine all docs blocks into a single big markdown document with section
# dividers and run through the Markdown processor. Then split it back out
# into separate sections.
markdown = docs_blocks.join("\n\n##### DIVIDER\n\n")
docs_html = Markdown.new(markdown, :smart).
to_html.
split(/\n*<h5>DIVIDER<\/h5>\n*/m)
# Combine all code blocks into a single big stream and run through either
# `pygmentize(1)` or <http://pygments.appspot.com>
code_stream = code_blocks.join("\n\n#{@options[:comment_chars]} DIVIDER\n\n")
if pygmentize?
code_html = highlight_pygmentize(code_stream)
else
code_html = highlight_webservice(code_stream)
end
# Do some post-processing on the pygments output to split things back
# into sections and remove partial `<pre>` blocks.
code_html = code_html.
split(/\n*<span class="c.?">#{@options[:comment_chars]} DIVIDER<\/span>\n*/m).
map { |code| code.sub(/\n?<div class="highlight"><pre>/m, '') }.
map { |code| code.sub(/\n?<\/pre><\/div>\n/m, '') }
# Lastly, combine the docs and code lists back into a list of two-tuples.
docs_html.zip(code_html)
end
# We `popen` a read/write pygmentize process in the parent and
# then fork off a child process to write the input.
def highlight_pygmentize(code)
code_html = nil
open("|pygmentize -l #{@options[:language]} -O encoding=utf-8 -f html", 'r+') do |fd|
pid =
fork {
fd.close_read
fd.write code
fd.close_write
exit!
}
fd.close_write
code_html = fd.read
fd.close_read
Process.wait(pid)
end
code_html
end
# Pygments is not one of those things that's trivial for a ruby user to install,
# so we'll fall back on a webservice to highlight the code if it isn't available.
def highlight_webservice(code)
Net::HTTP.post_form(
URI.parse('http://pygments.appspot.com/'),
{'lang' => @options[:language], 'code' => code}
).body
end
end
# And that's it.