CodeRay Library

CodeRay is a Ruby library for syntax highlighting.

I try to make CodeRay easy to use and intuitive, but at the same time fully featured, complete, fast and efficient.

See README.

It consists mainly of

• the main engine: CodeRay (Scanners::Scanner, Tokens, Encoders::Encoder)

• the plugin system: PluginHost, Plugin

• the scanners in CodeRay::Scanners

• the encoders in CodeRay::Encoders

• the styles in CodeRay::Styles

Here's a fancy graphic to light up this gray docu:

Documentation

See CodeRay, Encoders, Scanners, Tokens.

Usage

Remember you need RubyGems to use CodeRay, unless you have it in your load path. Run Ruby with -rubygems option if required.

Highlight Ruby code in a string as html

require 'coderay'
print CodeRay.scan('puts "Hello, world!"', :ruby).html

# prints something like this:
puts <span class="s">&quot;Hello, world!&quot;<%rspan>

Highlight C code from a file in a html div

require 'coderay'
print CodeRay.scan(File.read('ruby.h'), :c).div
print CodeRay.scan_file('ruby.h').html.div

You can include this div in your page. The used CSS styles can be printed with

% coderay_stylesheet

Highlight without typing too much

If you are one of the hasty (or lazy, or extremely curious) people, just run this file:

% ruby -rubygems /path/to/coderay/coderay.rb > example.html

and look at the file it created in your browser.

CodeRay Module

The CodeRay module provides convenience methods for the engine.

• The lang and format arguments select Scanner and Encoder to use. These are simply lower-case symbols, like :python or :html.

• All methods take an optional hash as last parameter, options, that is send to the Encoder / Scanner.

• Input and language are always sorted in this order: code, lang. (This is in alphabetical order, if you need a mnemonic ;)

You should be able to highlight everything you want just using these methods; so there is no need to dive into CodeRay's deep class hierarchy.

The examples in the demo directory demonstrate common cases using this interface.

Basic Access Ways

Read this to get a general view what CodeRay provides.

Scanning

Scanning means analysing an input string, splitting it up into Tokens. Each Token knows about what type it is: string, comment, class name, etc.

Each lang (language) has its own Scanner; for example, :ruby code is handled by CodeRay::Scanners::Ruby.

::scan

Scan a string in a given language into Tokens. This is the most common method to use.

::scan_file

Scan a file and guess the language using FileType.

The Tokens object you get from these methods can encode itself; see Tokens.

Encoding

Encoding means compiling Tokens into an output. This can be colored HTML or LaTeX, a textual statistic or just the number of non-whitespace tokens.

Each Encoder provides output in a specific format, so you select Encoders via formats like :html or :statistic.

::encode

Scan and encode a string in a given language.

::encode_tokens

Encode the given tokens.

::encode_file

Scan a file, guess the language using FileType and encode it.

All-in-One Encoding

::encode

Highlight a string with a given input and output format.

Instanciating

You can use an Encoder instance to highlight multiple inputs. This way, the setup for this Encoder must only be done once.

::encoder

Create an Encoder instance with format and options.

::scanner

Create an Scanner instance for lang, with " as default code.

To make use of ::scanner, use CodeRay::Scanner::code=.

The scanning methods provide more flexibility; we recommend to use these.

Reusing Scanners and Encoders

If you want to re-use scanners and encoders (because that is faster), see CodeRay::Duo for the most convenient (and recommended) interface.

# File lib/coderay.rb, line 132
def self.coderay_path *path
  File.join CODERAY_PATH, *path
end

# File lib/coderay.rb, line 196
def encode code, lang, format, options = {}
  encoder(format, options).encode code, lang, options
end

require 'coderay'
page = CodeRay.encode_file 'some_c_code.c', :html

# File lib/coderay.rb, line 221
def encode_file filename, format, options = {}
  tokens = scan_file filename, :auto, get_scanner_options(options)
  encode_tokens tokens, format, options
end

require 'coderay'

# Highlight a short Ruby code example in a HTML span
tokens = CodeRay.scan '1 + 2', :ruby
puts CodeRay.encode_tokens(tokens, :span)

# File lib/coderay.rb, line 209
def encode_tokens tokens, format, options = {}
  encoder(format, options).encode_tokens tokens, options
end

require 'coderay'

stats = CodeRay.encoder(:statistic)
stats.encode("puts 17 + 4\n", :ruby)

puts '%d out of %d tokens have the kind :integer.' % [
  stats.type_stats[:integer].count,
  stats.real_token_count
]
#-> 2 out of 4 tokens have the kind :integer.

# File lib/coderay.rb, line 260
def encoder format, options = {}
  Encoders[format].new options
end

# File lib/coderay.rb, line 278
def get_scanner_options options
  options.fetch :scanner_options, {}
end

# File lib/coderay.rb, line 232
def highlight code, lang, options = { :css => :class }, format = :div
  encode code, lang, format, options
end

# File lib/coderay.rb, line 242
def highlight_file filename, options = { :css => :class }, format = :div
  encode_file filename, format, options
end

require 'coderay'
page = CodeRay.scan("puts 'Hello, world!'", :ruby).html

# File lib/coderay.rb, line 167
def scan code, lang, options = {}, &block
  # FIXME: return a proxy for direct-stream encoding
  TokensProxy.new code, lang, options, block
end

require 'coderay'
page = CodeRay.scan_file('some_c_code.c').html

# File lib/coderay.rb, line 183
def scan_file filename, lang = :auto, options = {}, &block
  lang = FileType.fetch filename, :text, true if lang == :auto
  code = File.read filename
  scan code, lang, options, &block
end

# File lib/coderay.rb, line 268
def scanner lang, options = {}, &block
  Scanners[lang].new '', options, &block
end