Class: Rouge::RegexLexer::StateDSL

Inherits:
Object
  • Object
show all
Defined in:
lib/rouge/regex_lexer.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, &defn) ⇒ StateDSL

Returns a new instance of StateDSL.



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# File 'lib/rouge/regex_lexer.rb', line 77

def initialize(name, &defn)
  @name = name
  @defn = defn
  @rules = []
  @loaded = false
  @closed = false
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/rouge/regex_lexer.rb', line 76

def name
  @name
end

#rules ⇒ Object (readonly)

Returns the value of attribute rules.



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# File 'lib/rouge/regex_lexer.rb', line 76

def rules
  @rules
end

Instance Method Details

#appended(&defn) ⇒ Object 



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# File 'lib/rouge/regex_lexer.rb', line 101

def appended(&defn)
  parent_defn = @defn
  StateDSL.new(@name) do
    instance_eval(&parent_defn)
    instance_eval(&defn)
  end
end

#close! ⇒ Object (protected) 



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# File 'lib/rouge/regex_lexer.rb', line 188

def close!
  @closed = true
end

#context_sensitive?(re) ⇒ Boolean (protected)

Returns:

  • (Boolean) 


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# File 'lib/rouge/regex_lexer.rb', line 178

def context_sensitive?(re)
  source = re.source
  return true if source =~ /[(][?]<?[!=]/

  # anchors count as lookahead/behind
  return true if source =~ /[$^]/

  false
end

#mixin(state) ⇒ Object (protected)

Mix in the rules from another state into this state. The rules from the mixed-in state will be tried in order before moving on to the rest of the rules in this state.



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# File 'lib/rouge/regex_lexer.rb', line 195

def mixin(state)
  rules << state.to_s
end

#prepended(&defn) ⇒ Object 



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# File 'lib/rouge/regex_lexer.rb', line 93

def prepended(&defn)
  parent_defn = @defn
  StateDSL.new(@name) do
    instance_eval(&defn)
    instance_eval(&parent_defn)
  end
end

#rule(re, token, next_state = nil) ⇒ Object (protected) #rule(re, &callback) ⇒ Object (protected)

Define a new rule for this state.

Parameters:

  • re (Regexp) —

    a regular expression for this rule to test.

  • tok (String) (defaults to: nil) —

    the token type to yield if re matches.

  • next_state (#to_s) (defaults to: nil) —

    (optional) a state to push onto the stack if re matches. If next_state is :pop!, the state stack will be popped instead.

  • callback (Proc) —

    a block that will be evaluated in the context of the lexer if re matches. This block has access to a number of lexer methods, including Rouge::RegexLexer#push, Rouge::RegexLexer#pop!, Rouge::RegexLexer#token, and Rouge::RegexLexer#delegate. The first argument can be used to access the match groups.

Raises:



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# File 'lib/rouge/regex_lexer.rb', line 129

def rule(re, tok=nil, next_state=nil, &callback)
  raise ClosedState.new(self) if @closed

  if tok.nil? && callback.nil?
    raise "please pass `rule` a token to yield or a callback"
  end

  matches_empty = re =~ ''

  callback ||= case next_state
  when :pop!
    proc do |stream|
      puts "    yielding: #{tok.qualname}, #{stream[0].inspect}" if @debug
      @output_stream.call(tok, stream[0])
      puts "    popping stack: 1" if @debug
      @stack.pop or raise 'empty stack!'
    end
  when :push
    proc do |stream|
      puts "    yielding: #{tok.qualname}, #{stream[0].inspect}" if @debug
      @output_stream.call(tok, stream[0])
      puts "    pushing :#{@stack.last.name}" if @debug
      @stack.push(@stack.last)
    end
  when Symbol
    proc do |stream|
      puts "    yielding: #{tok.qualname}, #{stream[0].inspect}" if @debug
      @output_stream.call(tok, stream[0])
      state = @states[next_state] || self.class.get_state(next_state)
      puts "    pushing :#{state.name}" if @debug
      @stack.push(state)
    end
  when nil
    # cannot use an empty-matching regexp with no predicate
    raise InvalidRegex.new(re) if matches_empty

    proc do |stream|
      puts "    yielding: #{tok.qualname}, #{stream[0].inspect}" if @debug
      @output_stream.call(tok, stream[0])
    end
  else
    raise "invalid next state: #{next_state.inspect}"
  end

  rules << Rule.new(re, callback)

  close! if matches_empty && !context_sensitive?(re)
end

#to_state(lexer_class) ⇒ Object 



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# File 'lib/rouge/regex_lexer.rb', line 85

def to_state(lexer_class)
  load!
  rules = @rules.map do |rule|
    rule.is_a?(String) ? lexer_class.get_state(rule) : rule
  end
  State.new(@name, rules)
end