Class: Reader

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

Constant Summary collapse

T_EOF =

tokens

:t_eof
T_LPAREN = 
:t_lparen
T_RPAREN = 
:t_rparen
T_SYMBOL = 
:t_symbol
T_NUM = 
:t_num
T_STRING = 
:t_string
T_QUOTE = 
:t_quote
T_QUASIQUOTE = 
:t_quasiquote
T_UNQUOTE = 
:t_unquote
T_UNQUOTE_SPLICING = 
:t_unquote_splicing
T_FEEDTO = 
:t_feedto
T_DOT = 
:t_dot
T_LINEFEED = 
:t_linefeed
T_COMMENT = 
:t_comment

Instance Method Summary collapse

Constructor Details

#initialize(inport, sourcefile, debug = false) ⇒ Reader

inport is IO class



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# File 'lib/nendo.rb', line 197

def initialize( inport, sourcefile, debug = false )
  @chReader   = CharReader.new( inport, sourcefile )
  @curtoken   = nil
  @debug      = debug
end

Instance Method Details

#_read ⇒ Object

return value is [ S-expression-tree, eof-flag, valid-sexp-flag ]



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# File 'lib/nendo.rb', line 463

def _read
  case curtoken.kind
  when T_EOF
    [ Nil.new, true,  false ]
  when T_LINEFEED
    token
    [ Nil.new, false, false ]
  else
    [ sexp(),  false, true  ]
  end
end

#atom ⇒ Object 



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# File 'lib/nendo.rb', line 329

def atom
  cur = curtoken 
  printf( "  NonT: [%s] : [%s]\n", "atom", cur.str ) if @debug
  token
  case cur.kind
  when T_SYMBOL
    sym = cur.str.intern
    sym.setLispToken( cur )
    case sym
    when :true
      true
    when :false
      false
    when :nil
      nil
    else
      sym
    end
  when T_NUM
    if cur.str.match( /[.]/ ) # floating point
      cur.str.to_f
    else
      cur.str.to_i
    end
  when T_STRING
    cur.str
  when T_QUOTE
    :quote
  when T_QUASIQUOTE
    :quasiquote
  when T_UNQUOTE
    :unquote
  when T_UNQUOTE_SPLICING
    :unquote_splicing
  when T_DOT
    :dot_operator
  when T_FEEDTO
    :feedto
  else
    raise "Error: Unknown token in atom()"
  end
end

#curtoken ⇒ Object 



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# File 'lib/nendo.rb', line 322

def curtoken
  if !@curtoken
    self.token
  end
  @curtoken
end

#lineno ⇒ Object 



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# File 'lib/nendo.rb', line 211

def lineno
  @chReader.lineno
end

#list ⇒ Object

list := sexp

| atom ... atom
| atom ... . atom



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# File 'lib/nendo.rb', line 375

def list
  printf( "  NonT: [%s]\n", "list" ) if @debug
  dotted = false
  cells = []
  lastAtom = nil
  while true
    case curtoken.kind
    when T_LINEFEED
      token # skipEnter
    when T_EOF
      raise SyntaxError, "Error: unbalanced paren(1)"
    when T_LPAREN
      cells << Cell.new( sexp() )
    when T_RPAREN
      break
    when T_DOT
      if 0 == cells.length
        # (. symbol1 symbol2 ... ) form
        cells << Cell.new( atom() )
      else
        # ( symbol1 . symbol2 ... ) form
        token
        lastAtom = sexp()
      end
    when T_QUOTE , T_QUASIQUOTE , T_UNQUOTE , T_UNQUOTE_SPLICING
      cells << Cell.new( sexp() )
    else
      if lastAtom
        raise "Error : illegal dotted pair syntax."
      else
        cells << Cell.new( atom() )
      end
    end
  end
  ## setup list
  if 0 == cells.size
    Cell.new() # null list
  elsif 1 == cells.size
    if lastAtom
      cells.first.cdr = lastAtom
    end
    cells.first
  elsif 1 < cells.size
    ptr = cells.pop
    if lastAtom
      ptr.cdr = lastAtom
    end
    cells.reverse.each { |x|
      x.cdr = ptr
      ptr = x
    }
    cells.first
  end
end

#readwhile(exp) ⇒ Object 



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# File 'lib/nendo.rb', line 224

def readwhile( exp )
  ret = ""
  while true
    ch = @chReader.getc
    #printf( "      readwhile: [%02x]\n", ch ) if @debug
    if !ch # eof?
      break
    end
    if ch.chr.match( exp )
      ret += ch.chr
    else
      @chReader.ungetc( ch )
      break
    end
  end
  ret
end

#reset ⇒ Object 



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# File 'lib/nendo.rb', line 203

def reset
  @chReader.reset
end

#sexp ⇒ Object

sexp := ( list ) | ‘sexp | `sexp | atom



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# File 'lib/nendo.rb', line 437

def sexp
  printf( "  NonT: [%s]\n", "sexp" ) if @debug
  case curtoken.kind
  when T_LINEFEED
    token
    sexp()
  when T_EOF
    raise SyntaxError, "Error: unbalanced paren(2)"
  when T_LPAREN
    skipEnter
    token # consume '('
    ret = list()
    skipEnter
    token # consume ')'
    ret
  when T_RPAREN
    raise SyntaxError, "Error: unbalanced paren(3)"
  when T_QUOTE , T_QUASIQUOTE , T_UNQUOTE , T_UNQUOTE_SPLICING
    _atom = atom() ## "quote" symbol
    Cell.new( _atom, Cell.new( sexp() ))
  else
    atom()
  end
end

#skipEnter ⇒ Object 



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# File 'lib/nendo.rb', line 430

def skipEnter
  while T_LINEFEED == curtoken.kind
    token
  end
end

#skipspace ⇒ Object 



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# File 'lib/nendo.rb', line 215

def skipspace
  begin
    ch = @chReader.getc
    break if nil == ch # non eof?
    #printf( "      skipspace: [%02x]\n", ch ) if @debug
  end while ch.chr.match( /[ \t]/ )
  @chReader.ungetc( ch ) if nil != ch 
end

#sourcefile ⇒ Object 



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# File 'lib/nendo.rb', line 207

def sourcefile
  @chReader.sourcefile
end

#token ⇒ Object 



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# File 'lib/nendo.rb', line 315

def token
  begin
    tokenWithComment
  end while T_COMMENT == curtoken.kind
  curtoken
end

#tokenWithComment ⇒ Object 



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# File 'lib/nendo.rb', line 242

def tokenWithComment
  skipspace
  ch = @chReader.getc
  if nil == ch # eof?
    @curtoken = Token.new( T_EOF, "", @chReader.sourcefile, @chReader.lineno, @chReader.column )
  else
    str = ch.chr
    kind =
      case str
      when /[\']/
        T_QUOTE
      when /[\`]/
        T_QUASIQUOTE
      when /[,]/
        str += readwhile( /[@]/ )
        if 1 == str.length
          T_UNQUOTE
        else
          T_UNQUOTE_SPLICING
        end
      when '('
        T_LPAREN
      when ')'
        T_RPAREN
      when '.'
        str += readwhile( /[_a-zA-Z0-9!?.-]/ ).gsub( /[-]/, '_' )
        if 1 == str.length
          T_DOT
        else
          T_SYMBOL
        end
      when /[\r\n]/
        T_LINEFEED
      when /;/
        readwhile( /[^\r\n]/ )
        str = ""
        T_COMMENT
      when /[#!]/
        readwhile( /[^\r\n]/ )
        str = ""
        T_COMMENT
      when /[_a-zA-Z]/      # symbol
        str += readwhile( /[_a-zA-Z0-9!?*.-]/ ).gsub( /[-]/, '_' )
        T_SYMBOL
      when /[*\/=!<>&|%]/   # symbol
        str += readwhile( /[+*\/=!<>&|?%-]/ )
        if str.match( /^[=][>]$/ )
          T_FEEDTO
        else
          T_SYMBOL
        end
      when /[+-]/           # number
        str += readwhile( /[0-9.]/ )
        if 1 < str.length
          T_NUM
        else
          T_SYMBOL
        end
      when /[0-9]/           # number
        str += readwhile( /[0-9.]/ )
        T_NUM
      when /["]/             # String
        str = LispString.new( readwhile( /[^"]/ )) ; readwhile( /["]/ )
        T_STRING
      else
        str += readwhile( /[^ \t\r\n]/ )
        raise NameError, sprintf( "unknown token for Nendo [%s]", str )
      end
    printf( "    token: [%s] : %s   (%s:L%d:C%d)\n", str, kind.to_s, @chReader.sourcefile, @chReader.lineno, @chReader.column ) if @debug
    @curtoken = Token.new( kind, str, @chReader.sourcefile, @chReader.lineno, @chReader.column )
  end
end