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

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;</span>

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, <tt>:ruby</tt> code is
 handled by CodeRay::Scanners::Ruby.
CodeRay.scan:Scan a string in a given language into Tokens. This is the most common method to use.
CodeRay.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.

CodeRay.encode:Scan and encode a string in a given language.
CodeRay.encode_tokens:Encode the given tokens.
CodeRay.encode_file:Scan a file, guess the language using FileType and encode it.

All-in-One Encoding

CodeRay.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.

CodeRay.encoder:Create an Encoder instance with format and options.
CodeRay.scanner:Create an Scanner instance for lang, with ’’ as default code.

To make use of CodeRay.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.

Methods
Classes and Modules
Module CodeRay::Encoders
Module CodeRay::FileType
Module CodeRay::ForRedCloth
Module CodeRay::GZip
Module CodeRay::Plugin
Module CodeRay::PluginHost
Module CodeRay::Scanners
Module CodeRay::Styles
Class CodeRay::Duo
Class CodeRay::Tokens
Class CodeRay::TokensProxy
Class CodeRay::WordList
Constants
TokenKinds = Hash.new do |h, k| warn 'Undefined Token kind: %p' % [k] if $CODERAY_DEBUG
  A Hash of all known token kinds and their associated CSS classes.
VERSION = '1.0.0'
Public Class methods
encode(code, lang, format, options = {})

Encode a string.

This scans code with the the Scanner for lang and then encodes it with the Encoder for format. options will be passed to the Encoder.

See CodeRay::Encoder.encode.

→ show source

# File lib/coderay.rb, line 190
    def encode code, lang, format, options = {}
      encoder(format, options).encode code, lang, options
    end
encode_file(filename, format, options = {})

Encodes filename (a path to a code file) with the Scanner for lang.

See CodeRay.scan_file. Notice that the second argument is the output format, not the input language.

Example: 

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

→ show source

# File lib/coderay.rb, line 215
    def encode_file filename, format, options = {}
      tokens = scan_file filename, :auto, get_scanner_options(options)
      encode_tokens tokens, format, options
    end
encode_tokens(tokens, format, options = {})

Encode pre-scanned Tokens. Use this together with CodeRay.scan: 

 require 'coderay'

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

→ show source

# File lib/coderay.rb, line 203
    def encode_tokens tokens, format, options = {}
      encoder(format, options).encode_tokens tokens, options
    end
encoder(format, options = {})

Finds the Encoder class for format and creates an instance, passing options to it.

Example: 

 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.

→ show source

# File lib/coderay.rb, line 254
    def encoder format, options = {}
      Encoders[format].new options
    end
get_scanner_options(options)

Extract the options for the scanner from the options hash.

Returns an empty Hash if :scanner_options is not set.

This is used if a method like CodeRay.encode has to provide options for Encoder and scanner.

→ show source

# File lib/coderay.rb, line 272
    def get_scanner_options options
      options.fetch :scanner_options, {}
    end
highlight(code, lang, options = { :css => :class })

Highlight a string into a HTML <div>.

CSS styles use classes, so you have to include a stylesheet in your output.

See encode.

→ show source

# File lib/coderay.rb, line 226
    def highlight code, lang, options = { :css => :class }, format = :div
      encode code, lang, format, options
    end
highlight_file(filename, options = { :css => :class })

Highlight a file into a HTML <div>.

CSS styles use classes, so you have to include a stylesheet in your output.

See encode.

→ show source

# File lib/coderay.rb, line 236
    def highlight_file filename, options = { :css => :class }, format = :div
      encode_file filename, format, options
    end
scan(code, lang, options = {})

Scans the given code (a String) with the Scanner for lang.

This is a simple way to use CodeRay. Example: 

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

See also demo/demo_simple.

→ show source

# File lib/coderay.rb, line 161
    def scan code, lang, options = {}, &block
      # FIXME: return a proxy for direct-stream encoding
      TokensProxy.new code, lang, options, block
    end
scan_file(filename, lang = :auto, options = {})

Scans filename (a path to a code file) with the Scanner for lang.

If lang is :auto or omitted, the CodeRay::FileType module is used to determine it. If it cannot find out what type it is, it uses CodeRay::Scanners::Text.

Calls CodeRay.scan.

Example: 

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

→ show source

# File lib/coderay.rb, line 177
    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
scanner(lang, options = {})

Finds the Scanner class for lang and creates an instance, passing options to it.

See Scanner.new.

→ show source

# File lib/coderay.rb, line 262
    def scanner lang, options = {}, &block
      Scanners[lang].new '', options, &block
    end