Class: Evaluator

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

Overview

Translate S expression to Ruby expression and Evaluation

Instance Method Summary collapse

Methods included from BuiltinFunctions

#__assertFlat, #__assertList, #_car, #_cdr, #_cons, #_display, #_div, #_eq_QMARK, #_equal_QMARK, #_eqv_QMARK, #_exit, #_ge_QMARK, #_gt_QMARK, #_intern, #_le_QMARK, #_length, #_list, #_lt_QMARK, #_macro_QMARK, #_macroexpand_1, #_minus, #_mod, #_multi, #_newline, #_not, #_null_QMARK, #_number_QMARK, #_pair_QMARK, #_plus, #_print, #_printf, #_procedure_QMARK, #_range, #_read, #_require, #_reverse, #_sort, #_sprintf, #_string_QMARK, #_string_join, #_symbol_QMARK, #_to_list, #_to_s, #_uniq, #_write, #_write_to_string

Constructor Details

#initialize(debug = false) ⇒ Evaluator

Returns a new instance of Evaluator.



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# File 'lib/nendo.rb', line 694

def initialize( debug = false )
  @binding = binding
  @debug   = debug
  @alias   = {'+'        => 'plus',
              '-'        => 'minus',
              '*'        => 'multi',
              '/'        => 'div',
              '%'        => 'mod',
              '='        => 'eq?',
              '=='       => 'eq?',
              '>'        => 'gt?',
              '>='       => 'ge?',
              '<'        => 'lt?',
              '<='       => 'le?',
              '==='      => 'eqv?',
  }
  # built-in functions
  @sym = Hash.new
  self.methods.grep( /^_/ ) { |rubySymbol|
    @sym[ rubySymbol ] = self.method( rubySymbol )
  }

  # initialize global symbols
  rubyExp = @sym.keys.map { |name|
    sprintf( "%s = @sym[ '%s' ] ", name, name )
  }.join( " ; " )
  eval( rubyExp, @binding )

  # initialize buildin functions as Proc objects
  rubyExp = self.methods.select { |x|
    x.to_s.match( /^_/ )
  }.map { |name|
    sprintf( "%s = self.method( :%s ).to_proc", name, name )
  }.join( " ; " )
  eval( rubyExp, @binding )

  # reset gensym counter
  @gensym_counter = 0
end

Instance Method Details

#_enable_debug ⇒ Object 



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# File 'lib/nendo.rb', line 1136

def _enable_debug()
  @debug = true
end

#_eval(sexp) ⇒ Object 



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# File 'lib/nendo.rb', line 1132

def _eval( sexp )
  self.lispEval( sexp, "dynamic S-expression ( no source )", 1 )
end

#_gensym ⇒ Object 



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# File 'lib/nendo.rb', line 734

def _gensym( )
  @gensym_counter += 1
  sprintf( "__gensym__%d", @gensym_counter ).intern
end

#_load(filename) ⇒ Object 



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# File 'lib/nendo.rb', line 1115

def _load( filename )
  printer = Printer.new( @debug )
  open( filename ) {|f|
    reader = Reader.new( f, filename, false )
    while true
      lineno = reader.lineno
      s = reader._read
      if s[1] # EOF?
        break
      elsif Nil != s[0].class
        printf( "\n          readExp=<<< %s >>>\n", printer._print(s[0]) ) if @debug
        self.lispEval( s[0], reader.sourcefile, lineno )
      end
    end
  }
end

#apply(car, cdr, sourcefile, lineno, lambda_flag = false) ⇒ Object 



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# File 'lib/nendo.rb', line 939

def apply( car, cdr, sourcefile, lineno, lambda_flag = false )
  cdr.each { |x| 
    if Cell == x.class
      x.car = translate( x.car )
    end
  }
  execFunc( car, cdr, sourcefile, lineno, lambda_flag )
end

#callProcedure(origname, pred, args) ⇒ Object 



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# File 'lib/nendo.rb', line 817

def callProcedure( origname, pred, args )
  rubyArgument = toRubyArgument( origname, pred, args )
  pred.call( *rubyArgument )
end

#execFunc(funcname, args, sourcefile, lineno, lambda_flag) ⇒ Object 



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# File 'lib/nendo.rb', line 822

def execFunc( funcname, args, sourcefile, lineno, lambda_flag )
  case funcname
  when :set!   # `set!' special form
    sprintf( "%s = %s", toRubySymbol( args.car.to_s.sub( /^:/, "" )), toRubyValue( args.cdr.car ))
  when :error
    sprintf( 'begin raise RuntimeError, %s ; rescue => __e ;  __e.set_backtrace( ["%s:%d"] + __e.backtrace ) ; raise __e ; end ', toRubyValue( args.car ), sourcefile, lineno )
  else
    if (not lambda_flag) and isRubyInterface( funcname )
      # Ruby method
      #   1) convert arguments
      argStr  = args.map { |x| toRubyValue( x.car ) }.join( "," )
      #   2) generate caller code part
      sprintf( "%s( %s )", toRubySymbol( funcname ), argStr )
    else
      # Nendo function
      argStr  = args.map { |x| toRubyValue( x.car ) }.join( " ,Cell.new(" )
      argStr += args.map { |x| "" }.join( ")" )
      if lambda_flag
        "anonymouse"
        sprintf( "callProcedure( 'anonymouse', %s, Cell.new( %s ))", funcname, argStr )
      else
        origname = funcname.to_s
        funcname = funcname.to_s
        funcname = @alias[ funcname ] if @alias[ funcname ] 
        sprintf( "callProcedure( '%s', %s, Cell.new( %s ))", origname, toRubySymbol( funcname ), argStr )
      end
    end
  end
end

#genQuote(sexp, str = "") ⇒ Object 



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# File 'lib/nendo.rb', line 948

def genQuote( sexp, str = "" )
  origStr = str
  case sexp
  when Cell
    if sexp.isNull
      str += "Nil.new"
    else
      arr = sexp.map { |x| genQuote( x.car ) }
      str += "Cell.new("
      str += arr.join( " ,Cell.new(" )
      lastAtom = sexp.lastAtom
      str += "," + genQuote( lastAtom )  if lastAtom
      str += arr.map{ |e| ")" }.join
    end
  when Symbol
    str += sprintf( ":\"%s\"", sexp.to_s )
  when String
    str += sprintf( "\"%s\"", sexp )
  when TrueClass, FalseClass, NilClass  # reserved symbols
    str += toRubyValue( sexp )
  else
    str += sprintf( "%s", sexp )
  end
  str
end

#isRubyInterface(name) ⇒ Object 



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# File 'lib/nendo.rb', line 769

def isRubyInterface( name )
  name.to_s.match( /[.]/ )
end

#letArgumentList(sexp) ⇒ Object

insert quote in let argument list

((sym1 list1)
 (sym2 list2)
 (sym3 list3))

will be transformed

(((quote sym1) list1)
 ((quote sym2) list2)
 ((quote sym3) list3))



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# File 'lib/nendo.rb', line 1033

def letArgumentList( sexp )
  sexp.each { |arg|
    arg.car.car = Cell.new( :quote, Cell.new( arg.car.car ))
    arg.car.cdr = quoting( arg.car.cdr )
  }
  sexp
end

#lispCompile(sexp) ⇒ Object 



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# File 'lib/nendo.rb', line 1094

def lispCompile( sexp )
  converge = true
  begin
    newSexp  = macroexpand_1( sexp )
    converge = _equal_QMARK( newSexp, sexp )
    sexp = newSexp
  end until converge
  sexp
end

#lispEval(sexp, sourcefile, lineno) ⇒ Object 



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# File 'lib/nendo.rb', line 1104

def lispEval( sexp, sourcefile, lineno )
  sexp = lispCompile( sexp )
  sexp = quoting( sexp );
  if @debug
    printf( "\n          quoting=<<< %s >>>\n", (Printer.new())._print(sexp))
  end
  rubyExp = translate( sexp );
  printf( "          rubyExp=<<< %s >>>\n", rubyExp ) if @debug
  eval( rubyExp, @binding, sourcefile, lineno );
end

#macroexpand_1(sexp) ⇒ Object 



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# File 'lib/nendo.rb', line 1069

def macroexpand_1( sexp )
  case sexp
  when Cell
    if :quote == sexp.car
      sexp
    else
      sym = sexp.car.to_s
      sym = @alias[ sym ]  if @alias[ sym ]
      sym = toRubySymbol( sym )
      if isRubyInterface( sym ) 
        arr = sexp.map { |x| macroexpand_1( x.car ) }
        arr.to_list( sexp.lastAtom )
      elsif sexp.car.class == Symbol and eval( sprintf( "(defined? %s and LispMacro == %s.class)", sym,sym ), @binding )
        eval( sprintf( "@_macro = %s", sym ), @binding )
        callProcedure( sym, @_macro, sexp.cdr )
      else
        arr = sexp.map { |x| macroexpand_1( x.car ) }
        arr.to_list( sexp.lastAtom )
      end
    end
  else
    sexp
  end
end

#makeBegin(args) ⇒ Object 



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# File 'lib/nendo.rb', line 852

def makeBegin( args )
  ar = args.map { |e|
    translate( e.car )
  }
  "begin " + ar.join( ";" ) + " end"
end

#makeClosure(sym, args) ⇒ Object 



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# File 'lib/nendo.rb', line 877

def makeClosure( sym, args )
  first = args.car
  if args.car.car == :quote
    first   = args.car.cdr.car
  end
  rest    = args.cdr
  argStr  = toRubyParameter( first )
  str = case sym
        when :macro
          sprintf( "LispMacro.new { %s ", argStr )
        when :lambda
          sprintf( "     Proc.new { %s ", argStr )
        else
          raise "Error: makeClosure: unknown symbol type " + sym
        end
  ar = rest.map { |e|
    translate( e.car )
  }
  str += ar.join( ";" ) + "}"
end

#makeIf(args) ⇒ Object 



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# File 'lib/nendo.rb', line 898

def makeIf( args )
  _condition = translate( args.car )
  _then      = translate( args.cdr.car )
  _else      = nil
  if 2 < args.length
    _else    = translate( args.cdr.cdr.car )
  end
  if _else
    str = sprintf( "if ( %s ) then %s else %s end ", _condition, _then, _else )
  else
    str = sprintf( "if ( %s ) then %s end ", _condition, _then )
  end
end

#makeLet(args) ⇒ Object 



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# File 'lib/nendo.rb', line 912

def makeLet( args )
  _name = "___lambda"
  str = ""
  argvals = []
  if args.car.is_a? Nil
    # nothing to do
    str = sprintf( "begin %s = lambda { || ", _name )
    rest = args.cdr
  else
    if :quote == args.car.car
      _name = args.car.cdr.car.to_s
      args = args.cdr
    end
    rest = args.cdr
    argsyms = args.car.map { |x|
      toRubySymbol( x.car.car.cdr.car.to_s )
    }
    argvals = args.car.map { |x|
      translate( x.car.cdr.car )
    }
    str = sprintf( "begin %s = lambda { |%s| ", _name, argsyms.join( "," ))
  end
  ar = rest.map { |e|  translate( e.car ) }
  str += ar.join( ";" ) + "} ; "
  str += sprintf( "%s.call( %s ) end ", _name, argvals.join( "," ))
end

#quoting(sexp) ⇒ Object 



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# File 'lib/nendo.rb', line 1041

def quoting( sexp )
  case sexp
  when Cell
    if :quote == sexp.car or :quasiquote == sexp.car 
      sexp
    elsif :set! == sexp.car or :lambda == sexp.car or :macro == sexp.car
      sexp.cdr.car = Cell.new( :quote, Cell.new( sexp.cdr.car ))
      sexp.cdr.cdr = quoting( sexp.cdr.cdr )
      sexp
    elsif :let == sexp.car
      case sexp.cdr.car
      when Cell        # let
        sexp.cdr         = Cell.new( letArgumentList( sexp.cdr.car ),
                             quoting( sexp.cdr.cdr ))
      when Symbol      # named let
        sexp.cdr.car     = Cell.new( :quote, Cell.new( sexp.cdr.car ))
        sexp.cdr.cdr     = Cell.new( letArgumentList( sexp.cdr.cdr.car ),
                                     quoting( sexp.cdr.cdr.cdr ))
      end
      sexp
    else
      Cell.new( quoting( sexp.car ), quoting( sexp.cdr ))
    end
  else
    sexp
  end
end

#toLispSymbol(name) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/nendo.rb', line 773

def toLispSymbol( name )
  name = name.to_s  if Symbol == name.class
  raise ArgumentError if not ('_' == name[0])
  name = name[1..-1]
  name.gsub( /_AMARK/, '*' ).gsub( /_QMARK/, '?' ).gsub( /_EMARK/, '!' )
end

#toRubyArgument(origname, pred, args) ⇒ Object 



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# File 'lib/nendo.rb', line 780

def toRubyArgument( origname, pred, args )
  num = pred.arity
  if 0 == num
    raise ArgumentError, sprintf( "at function `%s'", origname )  if 0 != args.length
    []
  elsif 0 < num
    if args.isNull
      [ Nil.new ]
    else
      raise ArgumentError, sprintf( "at function `%s'", origname ) if num != args.length
      args.map { |x|  x.car }
    end
  else
    num = num.abs( )-1
    raise ArgumentError, sprintf( "at function `%s'", origname )  if num > args.length
    params = []
    rest = []
    args.each_with_index { |x,i|
      if i < num
        params << x.car
      else
        rest   << x.car
      end
    }
    result = []
    if 0 < params.length
      result = params
    end
    if 0 == rest.length
      result << Cell.new
    else
      result << rest.to_list
    end
    result
  end
end

#toRubyParameter(argform) ⇒ Object 



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# File 'lib/nendo.rb', line 859

def toRubyParameter( argform )
  argsyms = []
  rest = nil
  if Symbol == argform.class
    rest       = argform
  else
    argsyms    = argform.map { |x|  toRubySymbol( x.car ) }
    rest       = argform.lastAtom
  end
  if rest
    rest       = toRubySymbol( rest ) 
    argsyms    << "*__rest__"
    sprintf( "|%s| %s = __rest__[0] ; ", argsyms.join( "," ), rest )
  else
    sprintf( "|%s|",                     argsyms.join( "," ))
  end
end

#toRubySymbol(name) ⇒ Object 



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# File 'lib/nendo.rb', line 751

def toRubySymbol( name )
  name = name.to_s  if Symbol == name.class
  if 0 == name.length
    ""
  else
    arr = name.split( /[.]/ )
    arr[0] = arr[0].gsub( /[*]/, '_AMARK' ).gsub( /[?]/, '_QMARK' ).gsub( /[!]/, '_EMARK' ).gsub( /[-]/, '_' ).gsub( /["]/, '' )
    if arr[0].match( /^[A-Z]/ )
      # nothing to do
    elsif arr[0] == ""
      arr[0] = 'Kernel'
    else
      arr[0] = '_' + arr[0]
    end
    arr.join( "." )
  end
end

#toRubyValue(val) ⇒ Object 



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# File 'lib/nendo.rb', line 739

def toRubyValue( val )
  if NilClass == val.class
    "nil"
  elsif TrueClass == val.class
    val.to_s
  elsif FalseClass == val.class
    val.to_s
  else
    val.to_s
  end
end

#translate(sexp) ⇒ Object 



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# File 'lib/nendo.rb', line 974

def translate( sexp )
  str = ""
  case sexp
  when Cell
    if :quote == sexp.car
      genQuote( sexp.cdr.car )
    elsif sexp.isDotted
      print "Error: can't eval dotted pair"
      raise NameError
    elsif sexp.isNull
      str += "Cell.new()"
    elsif Cell == sexp.car.class
      if :lambda == sexp.car.car
        str += self.apply( translate( sexp.car ), sexp.cdr, sexp.car.car.sourcefile, sexp.car.car.lineno, true )
      else
        str += translate( sexp.car )
      end
    elsif :begin == sexp.car
      str += self.makeBegin( sexp.cdr )
    elsif :lambda == sexp.car
      str += self.makeClosure( :lambda, sexp.cdr )
    elsif :macro == sexp.car
      str += self.makeClosure( :macro, sexp.cdr )
    elsif :if == sexp.car
      str += self.makeIf( sexp.cdr )
    elsif :let == sexp.car
      str += self.makeLet( sexp.cdr )
    else
      str += self.apply( sexp.car, sexp.cdr, sexp.car.sourcefile, sexp.car.lineno )
    end
  else
    case sexp
    when Symbol
      sym = sexp.to_s
      sym = @alias[ sym ]  if @alias[ sym ]
      sym = toRubySymbol( sym )
      str += sprintf( 'begin %s ; rescue NameError => __e ; __e.set_backtrace( ["%s:%d"] + __e.backtrace ) ; raise __e ; end', sym, sexp.sourcefile, sexp.lineno )
    when Fixnum
      str += sexp.to_s
    when LispString
      str += sprintf( "\"%s\"", sexp )
    when Nil
      str += "Nil.new"
    when TrueClass, FalseClass, NilClass  # reserved symbols
      str += toRubyValue( sexp )
    else
      str += sexp.to_s
    end
  end
end