Class: Rouge::Lexer Abstract

Inherits:
Object
  • Object
show all
Includes:
Token::Tokens
Defined in:
lib/rouge/lexer.rb

Overview

This class is abstract.

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

Constant Summary

Constants included from Token::Tokens

Token::Tokens::Num, Token::Tokens::Str

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Token::Tokens

token

Constructor Details

#initialize(opts = {}) ⇒ Lexer

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

Parameters:

  • opts (Hash) (defaults to: {})

    a customizable set of options

Options Hash (opts):

  • :debug (Object)

    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.


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# File 'lib/rouge/lexer.rb', line 313

def initialize(opts={})
  @options = {}
  opts.each { |k, v| @options[k.to_s] = v }

  @debug = Lexer.debug_enabled? && bool_option('debug')
end

Instance Attribute Details

#optionsObject (readonly)

-*- instance methods -*- #


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# File 'lib/rouge/lexer.rb', line 303

def options
  @options
end

Class Method Details

.aliases(*args) ⇒ Object

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

Examples:

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

Lexer.find('eruby') # => Erb

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# File 'lib/rouge/lexer.rb', line 251

def aliases(*args)
  args.map!(&:to_s)
  args.each { |arg| Lexer.register(arg, self) }
  (@aliases ||= []).concat(args)
end

.allObject

Returns a list of all lexers.

Returns:

  • a list of all lexers.


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# File 'lib/rouge/lexer.rb', line 131

def all
  @all ||= registry.values.uniq
end

.assert_utf8!(str) ⇒ Object

Raises:

  • (EncodingError)

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# File 'lib/rouge/lexer.rb', line 285

def assert_utf8!(str)
  encoding = str.encoding.name
  return if encoding == 'US-ASCII' || encoding == 'UTF-8' || encoding == 'ASCII-8BIT'

  raise EncodingError.new(
    "Bad encoding: #{str.encoding.names.join(',')}. " +
    "Please convert your string to UTF-8."
  )
end

.continue_lex(*a, &b) ⇒ Object

In case #continue_lex is called statically, we simply begin a new lex from the beginning, since there is no state.

See Also:


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# File 'lib/rouge/lexer.rb', line 30

def continue_lex(*a, &b)
  lex(*a, &b)
end

.debug_enabled?Boolean

Returns:

  • (Boolean)

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# File 'lib/rouge/lexer.rb', line 205

def debug_enabled?
  (defined? @debug_enabled) ? true : false
end

.demo(arg = :absent) ⇒ Object

Specify or get a small demo string for this lexer


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# File 'lib/rouge/lexer.rb', line 124

def demo(arg=:absent)
  return @demo = arg unless arg == :absent

  @demo = File.read(demo_file, mode: 'rt:bom|utf-8')
end

.demo_file(arg = :absent) ⇒ Object

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


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# File 'lib/rouge/lexer.rb', line 117

def demo_file(arg=:absent)
  return @demo_file = Pathname.new(arg) unless arg == :absent

  @demo_file = Pathname.new(File.join(__dir__, 'demos', tag))
end

.desc(arg = :absent) ⇒ Object

Specify or get this lexer's description.


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# File 'lib/rouge/lexer.rb', line 99

def desc(arg=:absent)
  if arg == :absent
    @desc
  else
    @desc = arg
  end
end

.detect?(text) ⇒ Boolean

This method is abstract.

Return true if there is an in-text indication (such as a shebang or DOCTYPE declaration) that this lexer should be used.

Parameters:

Returns:

  • (Boolean)

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# File 'lib/rouge/lexer.rb', line 502

def self.detect?(text)
  false
end

.detectable?Boolean

Determine if a lexer has a method named :detect? defined in its singleton class.

Returns:

  • (Boolean)

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# File 'lib/rouge/lexer.rb', line 211

def detectable?
  return @detectable if defined?(@detectable)
  @detectable = singleton_methods(false).include?(:detect?)
end

.disable_debug!Object


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# File 'lib/rouge/lexer.rb', line 201

def disable_debug!
  remove_instance_variable :@debug_enabled if defined? @debug_enabled
end

.enable_debug!Object


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# File 'lib/rouge/lexer.rb', line 197

def enable_debug!
  @debug_enabled = true
end

.filenames(*fnames) ⇒ Object

Specify a list of filename globs associated with this lexer.

If a filename glob is associated with more than one lexer, this can cause a Guesser::Ambiguous error to be raised in various guessing methods. These errors can be avoided by disambiguation. Filename globs are disambiguated in one of two ways. Either the lexer will define a `self.detect?` method (intended for use with shebangs and doctypes) or a manual rule will be specified in Guessers::Disambiguation.

Examples:

class Ruby < Lexer
  filenames '*.rb', '*.ruby', 'Gemfile', 'Rakefile'
end

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# File 'lib/rouge/lexer.rb', line 270

def filenames(*fnames)
  (@filenames ||= []).concat(fnames)
end

.find(name) ⇒ Class<Rouge::Lexer>?

Given a name in string, return the correct lexer class.

Parameters:

  • name (String)

Returns:


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# File 'lib/rouge/lexer.rb', line 37

def find(name)
  registry[name.to_s]
end

.find_fancy(str, code = nil, additional_options = {}) ⇒ Object

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")
    

    If the code matches more than one lexer then Guesser::Ambiguous is raised.

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


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# File 'lib/rouge/lexer.rb', line 58

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 = {}, &fallback) ⇒ Class<Rouge::Lexer>

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

Parameters:

  • fallback (Proc)

    called if multiple lexers are detected. If omitted, Guesser::Ambiguous is raised.

  • info (Hash) (defaults to: {})

    a customizable set of options

Options Hash (info):

  • :mimetype (Object)

    A mimetype to guess by

  • :filename (Object)

    A filename to guess by

  • :source (Object)

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

Returns:

See Also:


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# File 'lib/rouge/lexer.rb', line 172

def guess(info={}, &fallback)
  lexers = guesses(info)

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

  if fallback
    fallback.call(lexers)
  else
    raise Guesser::Ambiguous.new(lexers)
  end
end

.guess_by_filename(fname) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 189

def guess_by_filename(fname)
  guess :filename => fname
end

.guess_by_mimetype(mt) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 185

def guess_by_mimetype(mt)
  guess :mimetype => mt
end

.guess_by_source(source) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 193

def guess_by_source(source)
  guess :source => source
end

.guesses(info = {}) ⇒ Object

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.


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# File 'lib/rouge/lexer.rb', line 140

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
  guessers << Guessers::Disambiguation.new(filename, source) if source && filename

  Guesser.guess(guessers, Lexer.all)
end

.lex(stream, opts = {}, &b) ⇒ Object

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

See Also:


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# File 'lib/rouge/lexer.rb', line 22

def lex(stream, opts={}, &b)
  new(opts).lex(stream, &b)
end

.mimetypes(*mts) ⇒ Object

Specify a list of mimetypes associated with this lexer.

Examples:

class Html < Lexer
  mimetypes 'text/html', 'application/xhtml+xml'
end

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# File 'lib/rouge/lexer.rb', line 280

def mimetypes(*mts)
  (@mimetypes ||= []).concat(mts)
end

.option(name, desc) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 111

def option(name, desc)
  option_docs[name.to_s] = desc
end

.option_docsObject


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# File 'lib/rouge/lexer.rb', line 107

def option_docs
  @option_docs ||= InheritableHash.new(superclass.option_docs)
end

.tag(t = nil) ⇒ Object

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

Examples:

class MyLexer < Lexer
  tag 'foo'
end

MyLexer.tag # => 'foo'

Lexer.find('foo') # => MyLexer

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# File 'lib/rouge/lexer.rb', line 235

def tag(t=nil)
  return @tag if t.nil?

  @tag = t.to_s
  Lexer.register(@tag, self)
end

.title(t = nil) ⇒ Object

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


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# File 'lib/rouge/lexer.rb', line 91

def title(t=nil)
  if t.nil?
    t = tag.capitalize
  end
  @title ||= t
end

Instance Method Details

#as_bool(val) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 320

def as_bool(val)
  case val
  when nil, false, 0, '0', 'false', 'off'
    false
  when Array
    val.empty? ? true : as_bool(val.last)
  else
    true
  end
end

#as_lexer(val) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 348

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) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 337

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) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 331

def as_string(val)
  return as_string(val.last) if val.is_a?(Array)

  val ? val.to_s : nil
end

#as_token(val) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 361

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) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 371

def bool_option(name, &default)
  name_str = name.to_s

  if @options.key?(name_str)
    as_bool(@options[name_str])
  else
    default ? default.call : false
  end
end

#continue_lex(string, &b) ⇒ Object

Continue the lex from the the current state without resetting


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# File 'lib/rouge/lexer.rb', line 456

def continue_lex(string, &b)
  return enum_for(:continue_lex, string, &b) unless block_given?

  # 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

#hash_option(name, defaults, &val_cast) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 397

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 = nil, &b) ⇒ Object

Note:

The use of :continue => true has been deprecated. A warning is issued if run with `$VERBOSE` set to true.

Note:

The use of arbitrary `opts` has never been supported, but we previously ignored them with no error. We now warn unconditionally.

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

Parameters:

  • opts (Hash) (defaults to: nil)

    a customizable set of options

Options Hash (opts):

  • :continue (Object)

    Continue the lex from the previous state (i.e. don't call #reset!)


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# File 'lib/rouge/lexer.rb', line 433

def lex(string, opts=nil, &b)
  if opts
    if (opts.keys - [:continue]).size > 0
      # improper use of options hash
      warn('Improper use of Lexer#lex - this method does not receive options.' +
           ' This will become an error in a future version.')
    end

    if opts[:continue]
      warn '`lex :continue => true` is deprecated, please use #continue_lex instead'
      return continue_lex(string, &b)
    end
  end

  return enum_for(:lex, string) unless block_given?

  Lexer.assert_utf8!(string)
  reset!

  continue_lex(string, &b)
end

#lexer_option(name, &default) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 385

def lexer_option(name, &default)
  as_lexer(@options.delete(name.to_s, &default))
end

#list_option(name, &default) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 389

def list_option(name, &default)
  as_list(@options.delete(name.to_s, &default))
end

#reset!Object

This method is abstract.

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


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# File 'lib/rouge/lexer.rb', line 419

def reset!
end

#stream_tokens(stream, &b) ⇒ Object

This method is abstract.

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

Parameters:

  • stream (StringScanner)

    the stream


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# File 'lib/rouge/lexer.rb', line 490

def stream_tokens(stream, &b)
  raise 'abstract'
end

#string_option(name, &default) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 381

def string_option(name, &default)
  as_string(@options.delete(name.to_s, &default))
end

#tagObject

delegated to tag


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# File 'lib/rouge/lexer.rb', line 479

def tag
  self.class.tag
end

#token_option(name, &default) ⇒ Object


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# File 'lib/rouge/lexer.rb', line 393

def token_option(name, &default)
  as_token(@options.delete(name.to_s, &default))
end