diff options
Diffstat (limited to 'lib/coderay/encoder.rb')
| -rw-r--r-- | lib/coderay/encoder.rb | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/lib/coderay/encoder.rb b/lib/coderay/encoder.rb new file mode 100644 index 0000000..5f6d511 --- /dev/null +++ b/lib/coderay/encoder.rb @@ -0,0 +1,210 @@ +module CodeRay
+
+ # This module holds class Encoder and its subclasses.
+ # For example, the HTML encoder is named CodeRay::Encoders::HTML
+ # can be found in coderay/encoders/html.
+ #
+ # Encoders also provides methods and constants for the register mechanism
+ # and the [] method that returns the Encoder class belonging to the
+ # given format.
+ module Encoders
+
+ # Raised if Encoders[] fails because:
+ # * an file could not be found
+ # * the requested Encoder is not registered
+ EncoderNotFound = Class.new Exception
+
+ # Loaded Encoders are saved here.
+ ENCODERS = Hash.new do |h, lang|
+ path = Encoders.path_to lang
+ lang = lang.to_sym
+ begin
+ require path
+ rescue LoadError
+ raise EncoderNotFound, "#{path} not found."
+ else
+ # Encoder should have registered by now
+ unless h[lang]
+ raise EncoderNotFound, "No Encoder for #{lang} found in #{path}."
+ end
+ end
+ h[lang]
+ end
+
+ class << self
+
+ # Every Encoder class must register itself for one or more +formats+
+ # by calling register_for, which calls this method.
+ #
+ # See CodeRay::Encoder.register_for.
+ def register encoder_class, *formats
+ for format in formats
+ ENCODERS[format.to_sym] = encoder_class
+ end
+ end
+
+ # Returns the Encoder for +lang+.
+ #
+ # Example:
+ # require 'coderay'
+ # yaml_encoder = CodeRay::Encoders[:yaml]
+ def [] lang
+ ENCODERS[lang]
+ end
+
+ # Alias for +[]+.
+ alias load []
+
+ # Returns the path to the encoder for format.
+ def path_to plugin
+ File.join 'coderay', 'encoders', "#{plugin}.rb"
+ end
+
+ end
+
+
+ # The Encoder base class. Together with CodeRay::Scanner and
+ # CodeRay::Tokens, it forms the highlighting triad.
+ #
+ # Encoder instances take a Tokens object and do something with it.
+ #
+ # The most common Encoder is surely the HTML encoder
+ # (CodeRay::Encoders::HTML). It highlights the code in a colorful
+ # html page.
+ # If you want the highlighted code in a div or a span instead,
+ # use its subclasses Div and Span.
+ class Encoder
+
+ attr_reader :token_stream
+
+ class << self
+
+ # Register this class for the given langs.
+ #
+ # Example:
+ # class MyEncoder < CodeRay::Encoders:Encoder
+ # register_for :myenc
+ # ...
+ # end
+ #
+ # See Encoder.register.
+ def register_for *args
+ Encoders.register self, *args
+ end
+
+ # Returns if the Encoder can be used in streaming mode.
+ def streamable?
+ is_a? Streamable
+ end
+
+ # If FILE_EXTENSION isn't defined, this method returns the downcase
+ # class name instead.
+ def const_missing sym
+ if sym == :FILE_EXTENSION
+ sym.to_s.downcase
+ else
+ super
+ end
+ end
+
+ end
+
+ # Subclasses are to store their default options in this constant.
+ DEFAULT_OPTIONS = { :stream => false }
+
+ # The options you gave the Encoder at creating.
+ attr_accessor :options
+
+ # Creates a new Encoder.
+ # +options+ is saved and used for all encode operations, as long as you
+ # don't overwrite it there by passing additional options.
+ #
+ # Encoder objects provide three encode methods:
+ # - encode simply takes a +code+ string and a +lang+
+ # - encode_tokens expects a +tokens+ object instead
+ # - encode_stream is like encode, but uses streaming mode.
+ #
+ # Each method has an optional +options+ parameter. These are added to
+ # the options you passed at creation.
+ def initialize options = {}
+ @options = self.class::DEFAULT_OPTIONS.merge options
+ raise "I am only the basic Encoder class. I can't encode anything. :(\n" +
+ "Use my subclasses." if self.class == Encoder
+ end
+
+ # Encode a Tokens object.
+ def encode_tokens tokens, options = {}
+ options = @options.merge options
+ setup options
+ compile tokens, options
+ finish options
+ end
+
+ # Encode the given +code+ after tokenizing it using the Scanner for
+ # +lang+.
+ def encode code, lang, options = {}
+ options = @options.merge options
+ scanner_options = options.fetch(:scanner_options, {})
+ tokens = CodeRay.scan code, lang, scanner_options
+ encode_tokens tokens, options
+ end
+
+ # You can use highlight instead of encode, if that seems
+ # more clear to you.
+ alias highlight encode
+
+ # Encode the given +code+ using the Scanner for +lang+ in streaming
+ # mode.
+ def encode_stream code, lang, options = {}
+ raise NotStreamableError, self unless kind_of? Streamable
+ options = @options.merge options
+ setup options
+ scanner_options = options.fetch :scanner_options, {}
+ @token_stream = CodeRay.scan_stream code, lang, scanner_options, &self
+ finish options
+ end
+
+ # Behave like a proc. The tokens method is converted to a proc.
+ def to_proc
+ method(:token).to_proc
+ end
+
+ protected
+
+ # Called with merged options before encoding starts.
+ # Sets @out to an empty string.
+ #
+ # See the HTML Encoder for an example of option caching.
+ def setup options
+ @out = ''
+ end
+
+ # Called with +text+ and +kind+ of the currently scanned token.
+ # For simple scanners, it's enougth to implement this method.
+ #
+ # Raises a NotImplementedError exception if it is not overwritten in
+ # subclass.
+ def token text, kind
+ raise NotImplementedError, "#{self.class}#token not implemented."
+ end
+
+ # Called with merged options after encoding starts.
+ # The return value is the result of encoding, typically @out.
+ def finish options
+ @out
+ end
+
+ # Do the encoding.
+ #
+ # The already created +tokens+ object must be used; it can be a
+ # TokenStream or a Tokens object.
+ def compile tokens, options
+ tokens.each(&self)
+ end
+
+ end
+
+ end
+end
+
+# vim:sw=2:ts=2:et:tw=78
|