class Rouge::Lexer

@abstract A lexer transforms text into a stream of `[token, chunk]` pairs.

Attributes

options[R]

-*- instance methods -*- #

Public Class Methods

aliases(*args) click to toggle source

Used to specify alternate names this lexer class may be found by.

@example

class Erb < Lexer
  tag 'erb'
  aliases 'eruby', 'rhtml'
end

Lexer.find('eruby') # => Erb
# File lib/rouge/lexer.rb, line 218
def aliases(*args)
  args.map!(&:to_s)
  args.each { |arg| Lexer.register(arg, self) }
  (@aliases ||= []).concat(args)
end
all() click to toggle source

@return a list of all lexers.

# File lib/rouge/lexer.rb, line 115
def all
  registry.values.uniq
end
analyze_text(text) click to toggle source

@abstract

Return a number between 0 and 1 indicating the likelihood that the text given should be lexed with this lexer. The default implementation returns 0. Values under 0.5 will only be used to disambiguate filename or mimetype matches.

@param [TextAnalyzer] text

the text to be analyzed, with a couple of handy methods on it,
like {TextAnalyzer#shebang?} and {TextAnalyzer#doctype?}
# File lib/rouge/lexer.rb, line 435
def self.analyze_text(text)
  0
end
assert_utf8!(str) click to toggle source

@private

# File lib/rouge/lexer.rb, line 245
def assert_utf8!(str)
  return if %w(US-ASCII UTF-8 ASCII-8BIT).include? str.encoding.name
  raise EncodingError.new(
    "Bad encoding: #{str.encoding.names.join(',')}. " +
    "Please convert your string to UTF-8."
  )
end
debug_enabled?() click to toggle source
# File lib/rouge/lexer.rb, line 181
def debug_enabled?
  !!@debug_enabled
end
demo(arg=:absent) click to toggle source

Specify or get a small demo string for this lexer

# File lib/rouge/lexer.rb, line 108
def demo(arg=:absent)
  return @demo = arg unless arg == :absent

  @demo = File.read(demo_file, encoding: 'utf-8')
end
demo_file(arg=:absent) click to toggle source

Specify or get the path name containing a small demo for this lexer (can be overriden by {demo}).

# File lib/rouge/lexer.rb, line 101
def demo_file(arg=:absent)
  return @demo_file = Pathname.new(arg) unless arg == :absent

  @demo_file = Pathname.new(__FILE__).dirname.join('demos', tag)
end
desc(arg=:absent) click to toggle source

Specify or get this lexer's description.

# File lib/rouge/lexer.rb, line 83
def desc(arg=:absent)
  if arg == :absent
    @desc
  else
    @desc = arg
  end
end
disable_debug!() click to toggle source
# File lib/rouge/lexer.rb, line 177
def disable_debug!
  @debug_enabled = false
end
enable_debug!() click to toggle source
# File lib/rouge/lexer.rb, line 173
def enable_debug!
  @debug_enabled = true
end
filenames(*fnames) click to toggle source

Specify a list of filename globs associated with this lexer.

@example

class Ruby < Lexer
  filenames '*.rb', '*.ruby', 'Gemfile', 'Rakefile'
end
# File lib/rouge/lexer.rb, line 230
def filenames(*fnames)
  (@filenames ||= []).concat(fnames)
end
find(name) click to toggle source

Given a string, return the correct lexer class.

# File lib/rouge/lexer.rb, line 25
def find(name)
  registry[name.to_s]
end
find_fancy(str, code=nil, additional_options={}) click to toggle source

Find a lexer, with fancy shiny features.

  • The string you pass can include CGI-style options

    Lexer.find_fancy('erb?parent=tex')
    
  • You can pass the special name 'guess' so we guess for you, and you can pass a second argument of the code to guess by

    Lexer.find_fancy('guess', "#!/bin/bash\necho Hello, world")
    

This is used in the Redcarpet plugin as well as Rouge's own markdown lexer for highlighting internal code blocks.

# File lib/rouge/lexer.rb, line 43
def find_fancy(str, code=nil, additional_options={})
  if str && !str.include?('?') && str != 'guess'
    lexer_class = find(str)
    return lexer_class && lexer_class.new(additional_options)
  end

  name, opts = str ? str.split('?', 2) : [nil, '']

  # parse the options hash from a cgi-style string
  opts = CGI.parse(opts || '').map do |k, vals|
    val = case vals.size
    when 0 then true
    when 1 then vals[0]
    else vals
    end

    [ k.to_s, val ]
  end

  opts = additional_options.merge(Hash[opts])

  lexer_class = case name
  when 'guess', nil
    self.guess(:source => code, :mimetype => opts['mimetype'])
  when String
    self.find(name)
  end

  lexer_class && lexer_class.new(opts)
end
guess(info={}) click to toggle source

Guess which lexer to use based on a hash of info.

@option info :mimetype

A mimetype to guess by

@option info :filename

A filename to guess by

@option info :source

The source itself, which, if guessing by mimetype or filename
fails, will be searched for shebangs, <!DOCTYPE ...> tags, and
other hints.

@see Lexer.analyze_text @see Lexer.guesses

# File lib/rouge/lexer.rb, line 152
def guess(info={})
  lexers = guesses(info)

  return Lexers::PlainText if lexers.empty?
  return lexers[0] if lexers.size == 1

  raise Guesser::Ambiguous.new(lexers)
end
guess_by_filename(fname) click to toggle source
# File lib/rouge/lexer.rb, line 165
def guess_by_filename(fname)
  guess :filename => fname
end
guess_by_mimetype(mt) click to toggle source
# File lib/rouge/lexer.rb, line 161
def guess_by_mimetype(mt)
  guess :mimetype => mt
end
guess_by_source(source) click to toggle source
# File lib/rouge/lexer.rb, line 169
def guess_by_source(source)
  guess :source => source
end
guesses(info={}) click to toggle source

Guess which lexer to use based on a hash of info.

This accepts the same arguments as Lexer.guess, but will never throw an error. It will return a (possibly empty) list of potential lexers to use.

# File lib/rouge/lexer.rb, line 124
def guesses(info={})
  mimetype, filename, source = info.values_at(:mimetype, :filename, :source)
  custom_globs = info[:custom_globs]

  guessers = (info[:guessers] || []).dup

  guessers << Guessers::Mimetype.new(mimetype) if mimetype
  guessers << Guessers::GlobMapping.by_pairs(custom_globs, filename) if custom_globs && filename
  guessers << Guessers::Filename.new(filename) if filename
  guessers << Guessers::Modeline.new(source) if source
  guessers << Guessers::Source.new(source) if source

  Guesser.guess(guessers, Lexer.all)
end
lex(stream, opts={}, &b) click to toggle source

Lexes `stream` with the given options. The lex is delegated to a new instance.

@see lex

# File lib/rouge/lexer.rb, line 20
def lex(stream, opts={}, &b)
  new(opts).lex(stream, &b)
end
mimetypes(*mts) click to toggle source

Specify a list of mimetypes associated with this lexer.

@example

class Html < Lexer
  mimetypes 'text/html', 'application/xhtml+xml'
end
# File lib/rouge/lexer.rb, line 240
def mimetypes(*mts)
  (@mimetypes ||= []).concat(mts)
end
new(opts={}) click to toggle source

Create a new lexer with the given options. Individual lexers may specify extra options. The only current globally accepted option is `:debug`.

@option opts :debug

Prints debug information to stdout.  The particular info depends
on the lexer in question.  In regex lexers, this will log the
state stack at the beginning of each step, along with each regex
tried and each stream consumed.  Try it, it's pretty useful.
# File lib/rouge/lexer.rb, line 271
def initialize(opts={})
  @options = {}
  opts.each { |k, v| @options[k.to_s] = v }

  @debug = Lexer.debug_enabled? && bool_option(:debug)
end
option(name, desc) click to toggle source
# File lib/rouge/lexer.rb, line 95
def option(name, desc)
  option_docs[name.to_s] = desc
end
option_docs() click to toggle source
# File lib/rouge/lexer.rb, line 91
def option_docs
  @option_docs ||= InheritableHash.new(superclass.option_docs)
end
tag(t=nil) click to toggle source

Used to specify or get the canonical name of this lexer class.

@example

class MyLexer < Lexer
  tag 'foo'
end

MyLexer.tag # => 'foo'

Lexer.find('foo') # => MyLexer
# File lib/rouge/lexer.rb, line 202
def tag(t=nil)
  return @tag if t.nil?

  @tag = t.to_s
  Lexer.register(@tag, self)
end
title(t=nil) click to toggle source

Specify or get this lexer's title. Meant to be human-readable.

# File lib/rouge/lexer.rb, line 75
def title(t=nil)
  if t.nil?
    t = tag.capitalize
  end
  @title ||= t
end

Protected Class Methods

register(name, lexer) click to toggle source

@private

# File lib/rouge/lexer.rb, line 187
def register(name, lexer)
  registry[name.to_s] = lexer
end

Private Class Methods

registry() click to toggle source
# File lib/rouge/lexer.rb, line 254
def registry
  @registry ||= {}
end

Public Instance Methods

as_bool(val) click to toggle source
# File lib/rouge/lexer.rb, line 278
def as_bool(val)
  case val
  when nil, false, 0, '0', 'off'
    false
  when Array
    val.empty? ? true : as_bool(val.last)
  else
    true
  end
end
as_lexer(val) click to toggle source
# File lib/rouge/lexer.rb, line 306
def as_lexer(val)
  return as_lexer(val.last) if val.is_a?(Array)
  return val.new(@options) if val.is_a?(Class) && val < Lexer

  case val
  when Lexer
    val
  when String
    lexer_class = Lexer.find(val)
    lexer_class && lexer_class.new(@options)
  end
end
as_list(val) click to toggle source
# File lib/rouge/lexer.rb, line 295
def as_list(val)
  case val
  when Array
    val.flat_map { |v| as_list(v) }
  when String
    val.split(',')
  else
    []
  end
end
as_string(val) click to toggle source
# File lib/rouge/lexer.rb, line 289
def as_string(val)
  return as_string(val.last) if val.is_a?(Array)

  val ? val.to_s : nil
end
as_token(val) click to toggle source
# File lib/rouge/lexer.rb, line 319
def as_token(val)
  return as_token(val.last) if val.is_a?(Array)
  case val
  when Token
    val
  else
    Token[val]
  end
end
bool_option(name, &default) click to toggle source
# File lib/rouge/lexer.rb, line 329
def bool_option(name, &default)
  if @options.key?(name.to_s)
    as_bool(@options[name.to_s])
  else
    default ? default.call : false
  end
end
hash_option(name, defaults, &val_cast) click to toggle source
# File lib/rouge/lexer.rb, line 353
def hash_option(name, defaults, &val_cast)
  name = name.to_s
  out = defaults.dup

  base = @options.delete(name.to_s)
  base = {} unless base.is_a?(Hash)
  base.each { |k, v| out[k.to_s] = val_cast ? val_cast.call(v) : v }

  @options.keys.each do |key|
    next unless key =~ /(\w+)\[(\w+)\]/ and $1 == name
    value = @options.delete(key)

    out[$2] = val_cast ? val_cast.call(value) : value
  end

  out
end
lex(string, opts={}, &b) click to toggle source

Given a string, yield [token, chunk] pairs. If no block is given, an enumerator is returned.

@option opts :continue

Continue the lex from the previous state (i.e. don't call #reset!)
# File lib/rouge/lexer.rb, line 383
def lex(string, opts={}, &b)
  return enum_for(:lex, string, opts) unless block_given?

  Lexer.assert_utf8!(string)

  reset! unless opts[:continue]

  # consolidate consecutive tokens of the same type
  last_token = nil
  last_val = nil
  stream_tokens(string) do |tok, val|
    next if val.empty?

    if tok == last_token
      last_val << val
      next
    end

    b.call(last_token, last_val) if last_token
    last_token = tok
    last_val = val
  end

  b.call(last_token, last_val) if last_token
end
lexer_option(name, &default) click to toggle source
# File lib/rouge/lexer.rb, line 341
def lexer_option(name, &default)
  as_lexer(@options.delete(name.to_s, &default))
end
list_option(name, &default) click to toggle source
# File lib/rouge/lexer.rb, line 345
def list_option(name, &default)
  as_list(@options.delete(name.to_s, &default))
end
reset!() click to toggle source

@abstract

Called after each lex is finished. The default implementation is a noop.

# File lib/rouge/lexer.rb, line 375
def reset!
end
stream_tokens(stream, &b) click to toggle source

@abstract

Yield `[token, chunk]` pairs, given a prepared input stream. This must be implemented.

@param [StringScanner] stream

the stream
# File lib/rouge/lexer.rb, line 421
def stream_tokens(stream, &b)
  raise 'abstract'
end
string_option(name, &default) click to toggle source
# File lib/rouge/lexer.rb, line 337
def string_option(name, &default)
  as_string(@options.delete(name.to_s, &default))
end
tag() click to toggle source

delegated to {Lexer.tag}

# File lib/rouge/lexer.rb, line 410
def tag
  self.class.tag
end
token_option(name, &default) click to toggle source
# File lib/rouge/lexer.rb, line 349
def token_option(name, &default)
  as_token(@options.delete(name.to_s, &default))
end