Class: Nydp::Tokeniser

Inherits:
Object show all
Defined in:
lib/nydp/tokeniser.rb

Constant Summary collapse

BACKSLASH = 
/\\/.freeze
COMMENT = 
/;;?.*$/.freeze
QUOTE = 
/"/.freeze
PIPE = 
/\|/.freeze
LIST_PFX = 
/[^\s()]*\(/.freeze
BRACE_PFX = 
/[^\s()\}\{]*\{/.freeze
RPAREN = 
/\)/.freeze
RBRACE = 
/\}/.freeze
FLOAT = 
/[-+]?[0-9]*\.[0-9]+([eE][-+]?[0-9]+)?/.freeze
INTEGER = 
/[-+]?[0-9]+/.freeze
ATOM_PIPE = 
/[^\s()"{}\|]+\|/.freeze
ATOM = 
/[^\s()"{}\|]+/.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(reader) ⇒ Tokeniser 



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# File 'lib/nydp/tokeniser.rb', line 20

def initialize reader
  @reader = reader
  @scanner = StringScanner.new("")
end

Instance Attribute Details

#finished ⇒ Object

Returns the value of attribute finished.



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# File 'lib/nydp/tokeniser.rb', line 18

def finished
  @finished
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/nydp/tokeniser.rb', line 18

def state
  @state
end

Instance Method Details

#close_delimiter?(scanner, delim) ⇒ Boolean 



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# File 'lib/nydp/tokeniser.rb', line 35

def close_delimiter? scanner, delim
  return (no_more? ? '' : nil) if (delim == :eof)
  scanner.scan(delim)
end

#next_string_fragment(open_delimiter, close_delimiter, interpolation_sign, interpolation_escapes = { }) ⇒ Object 



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# File 'lib/nydp/tokeniser.rb', line 40

def next_string_fragment open_delimiter, close_delimiter, interpolation_sign, interpolation_escapes={ }
  s = @scanner
  rep = open_delimiter.to_s
  string = ""
  while (!no_more?)
    if esc = s.scan(BACKSLASH)
      rep    << esc
      ch = s.getch
      case ch
        when "n" ; string << "\n"
        when "t" ; string << "\t"
        else       string << ch
      end
      rep << ch
    elsif closer = close_delimiter?(s, close_delimiter)
      rep << closer
      return StringFragmentCloseToken.new(string, rep)
    elsif interpolation_sign
      escaped = false
      interpolation_escapes.each do |esc, repl|
        if !escaped && (escape = s.scan esc)
          string << ((repl == true) ? escape : repl)
          rep    << escape
          escaped = true
        end
      end
      if !escaped && (start_interpolation = s.scan(interpolation_sign))
        rep << start_interpolation
        return StringFragmentToken.new(string, rep)
      else
        ch = s.getch
        string << ch
        rep    << ch
      end
    else
      ch = s.getch
      string << ch
      rep    << ch
    end
  end

  return StringFragmentCloseToken.new(string, rep) if close_delimiter == :eof
end

#next_token ⇒ Object 



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# File 'lib/nydp/tokeniser.rb', line 84

def next_token
  s = @scanner
  tok = nil
  while !tok
    if no_more?
      @finished = true
      return nil
    elsif comment = s.scan(COMMENT)
      tok = [:comment, comment.gsub(/^;;?\s*/, '').strip]
    elsif open_str = s.scan(QUOTE)
      tok = [:string_open_delim, open_str]
    elsif open_sym = s.scan(PIPE)
      tok = [:sym_open_delim, open_sym]
    elsif list_prefix = s.scan(LIST_PFX)
      tok = [:left_paren, list_prefix[0...-1]]
    elsif list_prefix = s.scan(BRACE_PFX)
      tok = [:left_brace, list_prefix[0...-1]]
    elsif s.scan(RPAREN)
      tok = [:right_paren]
    elsif s.scan(RBRACE)
      tok = [:right_brace]
    elsif number = s.scan(FLOAT)
      tok = [:number, number.to_f]
    elsif integer = s.scan(INTEGER)
      tok = [:number, integer.to_i]
    elsif atom = s.scan(ATOM_PIPE)
      atom = atom[0...-1]
      rest = next_string_fragment("|", PIPE, nil) || Nydp::StringFragmentToken.new("", "")
      tok = [:symbol, "#{atom}#{rest.string}"]
    elsif atom = s.scan(ATOM)
      tok = [:symbol, atom]
    else
      s.getch
    end
  end
  tok
end

#no_more? ⇒ Boolean 



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# File 'lib/nydp/tokeniser.rb', line 25

def no_more?
  if @scanner.eos?
    nextline = @reader.nextline
    return true if nextline.nil?
    @scanner << nextline
  end

  false
end