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|
require "stringio"
module CodeRay
# This module holds the Encoder class 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
extend PluginHost
plugin_path File.dirname(__FILE__), 'encoders'
# = Encoder
#
# The Encoder base class. Together with Scanner and
# 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
extend Plugin
plugin_host Encoders
attr_reader :token_stream
class << self
# 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
plugin_id
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. :( 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 = CodeRay.get_scanner_options(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 = CodeRay.get_scanner_options options
@token_stream =
CodeRay.scan_stream code, lang, scanner_options, &self
finish options
end
# Behave like a proc. The token method is converted to a proc.
def to_proc
method(:token).to_proc
end
# Return the default file extension for outputs of this encoder.
def file_extension
self.class::FILE_EXTENSION
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.
#
# By default, it calls text_token or block_token, depending on
# whether +text+ is a String.
def token text, kind
out =
if text.is_a? ::String # Ruby 1.9: :open.is_a? String
text_token text, kind
elsif text.is_a? ::Symbol
block_token text, kind
else
raise 'Unknown token text type: %p' % text
end
@out << out if @out
end
def text_token text, kind
end
def block_token action, kind
case action
when :open
open_token kind
when :close
close_token kind
else
raise 'unknown block action: %p' % action
end
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
|
