Class: Lexr

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

Defined Under Namespace

Classes: Dsl, MatchData, Rule, Token, UnmatchableTextError

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(text, rules) ⇒ Lexr

Returns a new instance of Lexr.



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# File 'lib/lexr.rb', line 8

def initialize(text, rules)
  @text, @rules = text, rules
  @current = Lexr::Token.start
  @position = 0
end

Class Method Details

.that(&block) ⇒ Object 



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# File 'lib/lexr.rb', line 2

def self.that(&block)
  dsl = Lexr::Dsl.new
  block.arity == 1 ? block[dsl] : dsl.instance_eval(&block)
  dsl
end

Instance Method Details

#current ⇒ Object 



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# File 'lib/lexr.rb', line 34

def current
  @current
end

#end? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/lexr.rb', line 38

def end?
  @current == Lexr::Token.end
end

#next ⇒ Object

Raises:



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# File 'lib/lexr.rb', line 14

def next
  return @current = Lexr::Token.end if @position >= @text.length
  @rules.each do |rule|
    next unless result = rule.match(unprocessed_text, @current)
    @position += result.characters_matched
    return self.next if rule.ignore?
    return @current = result.token
  end
  raise Lexr::UnmatchableTextError.new(unprocessed_text[0..0], @position)
end

#peek ⇒ Object 



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# File 'lib/lexr.rb', line 25

def peek
  pos = @position
  cur = @current
  result = self.send :next
  @position = pos
  @current = cur
  result
end