Class: H2o::ArgumentLexer

Inherits:

Object

• Object
• H2o::ArgumentLexer

Defined in:

lib/h2o/parser.rb

Class Method Summary

• .lex(argstring) ⇒ Object

Instance Method Summary

• #initialize(argstring, pos = 0) ⇒ ArgumentLexer constructor

  A new instance of ArgumentLexer.

• #lexer ⇒ Object

Constructor Details

#initialize(argstring, pos = 0) ⇒ ArgumentLexer

Returns a new instance of ArgumentLexer.

# File 'lib/h2o/parser.rb', line 155

def initialize(argstring, pos = 0)
  @argument = argstring
end

Class Method Details

.lex(argstring) ⇒ Object

# File 'lib/h2o/parser.rb', line 159

def self.lex(argstring)
  new(argstring).lexer()
end

Instance Method Details

#lexer ⇒ Object

# File 'lib/h2o/parser.rb', line 163

def lexer
  s = StringScanner.new(@argument)
  state = :initial
  result = []
  while ! s.eos?
    next if s.scan(WHITESPACE_RE)
    
    if state == :initial
      if match = s.scan(OPERATOR_RE)
        result << [:operator, match]
      elsif match = s.scan(BOOLEAN_RE)
        result << [:boolean, match]
      elsif match = s.scan(NIL_RE)
        result << [:nil, match]
      elsif match = s.scan(NAMED_ARGS_RE)
        result << [:named_argument, match]
      elsif match = s.scan(NAME_RE)
        result << [:name, match]
      elsif match = s.scan(PIPE_RE)
        state = :filter
        result << [:filter_start, nil]
      elsif match = s.scan(SEPERATOR_RE)
        result << [:seperator, nil]
      elsif match = s.scan(STRING_RE)
        result << [:string, match]
      elsif match = s.scan(NUMBER_RE)
        result << [:number, match]
      else 
        raise SyntaxError, "unexpected character #{s.getch} in tag"
      end
    elsif state == :filter
      if match = s.scan(PIPE_RE)
        result << [:filter_end, nil]
        result << [:filter_start, nil]
      elsif match = s.scan(SEPERATOR_RE)
        result << [:seperator, nil]
      elsif match = s.scan(FILTER_END_RE)
        result << [:filter_end, nil]
        state = :initial
      elsif match = s.scan(BOOLEAN_RE)
        result << [:boolean, match]
      elsif match = s.scan(NIL_RE)
        result << [:nil, match]
      elsif match = s.scan(NAMED_ARGS_RE)
        result << [:named_argument, match]
      elsif match = s.scan(NAME_RE)
        result << [:name, match]
      elsif match = s.scan(STRING_RE)
        result << [:string, match]
      elsif match = s.scan(NUMBER_RE)
        result << [:number, match]
      else 
        raise SyntaxError, "unexpected character #{s.getch} in filter"
      end
    end
  end
  result << [:filter_end, nil]  if state == :filter

  result
end