class Rouge::Lexer
@abstract A lexer transforms text into a stream of ‘[token, chunk]` pairs.
Attributes
-*- instance methods -*- #
Public Class Methods
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 250 def aliases(*args) args.map!(&:to_s) args.each { |arg| Lexer.register(arg, self) } (@aliases ||= []).concat(args) end
@return a list of all lexers.
# File lib/rouge/lexer.rb, line 130 def all @all ||= registry.values.uniq end
@private
# File lib/rouge/lexer.rb, line 284 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
In case continue_lex
is called statically, we simply begin a new lex from the beginning, since there is no state.
@see continue_lex
# File lib/rouge/lexer.rb, line 29 def continue_lex(*a, &b) lex(*a, &b) end
# File lib/rouge/lexer.rb, line 204 def debug_enabled? (defined? @debug_enabled) ? true : false end
Specify or get a small demo string for this lexer
# File lib/rouge/lexer.rb, line 123 def demo(arg=:absent) return @demo = arg unless arg == :absent @demo = File.read(demo_file, mode: 'rt:bom|utf-8') end
Specify or get the path name containing a small demo for this lexer (can be overriden by {demo}).
# File lib/rouge/lexer.rb, line 116 def demo_file(arg=:absent) return @demo_file = Pathname.new(arg) unless arg == :absent @demo_file = Pathname.new(File.join(__dir__, 'demos', tag)) end
Specify or get this lexer’s description.
# File lib/rouge/lexer.rb, line 98 def desc(arg=:absent) if arg == :absent @desc else @desc = arg end end
@abstract
Return true if there is an in-text indication (such as a shebang or DOCTYPE declaration) that this lexer should be used.
@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 501 def self.detect?(text) false end
Determine if a lexer has a method named :detect?
defined in its singleton class.
# File lib/rouge/lexer.rb, line 210 def detectable? return @detectable if defined?(@detectable) @detectable = singleton_methods(false).include?(:detect?) end
# File lib/rouge/lexer.rb, line 200 def disable_debug! remove_instance_variable :@debug_enabled if defined? @debug_enabled end
# File lib/rouge/lexer.rb, line 196 def enable_debug! @debug_enabled = true end
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
.
@example
class Ruby < Lexer filenames '*.rb', '*.ruby', 'Gemfile', 'Rakefile' end
# File lib/rouge/lexer.rb, line 269 def filenames(*fnames) (@filenames ||= []).concat(fnames) end
Given a name in string, return the correct lexer class. @param [String] name @return [Class<Rouge::Lexer>,nil]
# File lib/rouge/lexer.rb, line 36 def find(name) registry[name.to_s] end
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.
# File lib/rouge/lexer.rb, line 57 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 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.
@param [Proc] fallback called if multiple lexers are detected.
If omitted, Guesser::Ambiguous is raised.
@see Lexer.detect?
@see Lexer.guesses
@return [Class<Rouge::Lexer>]
# File lib/rouge/lexer.rb, line 171 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
# File lib/rouge/lexer.rb, line 188 def guess_by_filename(fname) guess :filename => fname end
# File lib/rouge/lexer.rb, line 184 def guess_by_mimetype(mt) guess :mimetype => mt end
# File lib/rouge/lexer.rb, line 192 def guess_by_source(source) guess :source => source end
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 139 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
Lexes ‘stream` with the given options. The lex is delegated to a new instance.
@see lex
# File lib/rouge/lexer.rb, line 21 def lex(stream, opts={}, &b) new(opts).lex(stream, &b) end
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 279 def mimetypes(*mts) (@mimetypes ||= []).concat(mts) end
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 312 def initialize(opts={}) @options = {} opts.each { |k, v| @options[k.to_s] = v } @debug = Lexer.debug_enabled? && bool_option('debug') end
# File lib/rouge/lexer.rb, line 110 def option(name, desc) option_docs[name.to_s] = desc end
# File lib/rouge/lexer.rb, line 106 def option_docs @option_docs ||= InheritableHash.new(superclass.option_docs) end
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 234 def tag(t=nil) return @tag if t.nil? @tag = t.to_s Lexer.register(@tag, self) end
Specify or get this lexer’s title. Meant to be human-readable.
# File lib/rouge/lexer.rb, line 90 def title(t=nil) if t.nil? t = tag.capitalize end @title ||= t end
Protected Class Methods
@private
# File lib/rouge/lexer.rb, line 217 def register(name, lexer) # reset an existing list of lexers @all = nil if defined?(@all) registry[name.to_s] = lexer end
Private Class Methods
# File lib/rouge/lexer.rb, line 295 def registry @registry ||= {} end
Public Instance Methods
# File lib/rouge/lexer.rb, line 319 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
# File lib/rouge/lexer.rb, line 347 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
# File lib/rouge/lexer.rb, line 336 def as_list(val) case val when Array val.flat_map { |v| as_list(v) } when String val.split(',') else [] end end
# File lib/rouge/lexer.rb, line 330 def as_string(val) return as_string(val.last) if val.is_a?(Array) val ? val.to_s : nil end
# File lib/rouge/lexer.rb, line 360 def as_token(val) return as_token(val.last) if val.is_a?(Array) case val when Token val else Token[val] end end
# File lib/rouge/lexer.rb, line 370 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 the lex from the the current state without resetting
# File lib/rouge/lexer.rb, line 455 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
# File lib/rouge/lexer.rb, line 396 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[$2] = val_cast ? val_cast.call(value) : value end out end
Given a string, yield [token, chunk] pairs. If no block is given, an enumerator is returned.
@option opts :continue
Continue the lex from the previous state (i.e. don't call #reset!)
@note The use of :continue => true has been deprecated. A warning is
issued if run with `$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.
# File lib/rouge/lexer.rb, line 432 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
# File lib/rouge/lexer.rb, line 384 def lexer_option(name, &default) as_lexer(@options.delete(name.to_s, &default)) end
# File lib/rouge/lexer.rb, line 388 def list_option(name, &default) as_list(@options.delete(name.to_s, &default)) end
@abstract
Called after each lex is finished. The default implementation is a noop.
# File lib/rouge/lexer.rb, line 418 def reset! end
@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 489 def stream_tokens(stream, &b) raise 'abstract' end
# File lib/rouge/lexer.rb, line 380 def string_option(name, &default) as_string(@options.delete(name.to_s, &default)) end
delegated to {Lexer.tag}
# File lib/rouge/lexer.rb, line 478 def tag self.class.tag end
# File lib/rouge/lexer.rb, line 392 def token_option(name, &default) as_token(@options.delete(name.to_s, &default)) end