DZone Snippets: type code

DATATYPE-NAME?

gregg.irwin (Gregg Irwin) — Thu, 16 Nov 2006 05:08:31 GMT



datatype-name?: func [val [string!]] [datatype? get/any load val]

CAST

gregg.irwin (Gregg Irwin) — Thu, 16 Nov 2006 05:07:50 GMT



cast: func [value type] [to type value]

CAN-CAST?

gregg.irwin (Gregg Irwin) — Thu, 16 Nov 2006 05:07:28 GMT



can-cast?: func [value type] [not error? try [to type value]]]

CAST function - Convert a value referenced by a word to a new datatype. Dialected

gregg.irwin (Gregg Irwin) — Thu, 25 May 2006 03:09:06 GMT



    cast: func [ ; convert coerce

        "Convert a value referenced by a word to a new datatype."

        input [block!] "A word, and the target datatype."

        /local words type val

    ] [

        parse input [

            some [

                copy words to 'to skip set type any-type! (

                    ;while [pos: find words 'and] [remove pos]

                    remove-each word words [word = 'and]

                    foreach word words [

                        val: get/any word

                        set/any word to either word? type [get type] [type] val

                    ]

                )

            ]

        ]

    ]

    comment {

        a: "A-0001"

        b: #B002

        c: 300

        d:

`e: 'test cast [a to issue!] print mold :a cast [b to tag!] print mold :b cast [c to decimal!] print mold :c cast [a b c to string!] print remold [:a :b :c] cast [a b and c to issue!] print remold [:a :b :c] cast [ a b and c to tag! and d and e to issue! ] print remold [:a :b :c :d :e] cast [a b c to d e to "x"] print remold [:a :b :c :d :e] }`

A dynamic form of the class statement.

korakot (Korakot Chaovavanich) — Fri, 17 Mar 2006 20:21:27 GMT

These 2 methods are equivalent.



# method 1

class X(object):

    a = 1



# method 2

X = type('X', (object,), dict(a=1))

isinstance and issubclass

korakot (Korakot Chaovavanich) — Thu, 09 Mar 2006 07:23:50 GMT



>>> class P(object):  # parent class

	pass



>>> class K(P):       # subclass

	pass



>>> k = K()           # instace

>>> isinstance(k, K)

True

>>> isinstance(k, P)

True

>>> isinstance(K, P)  # K is a class

False



>>> issubclass(K, P)

True

>>> issubclass(k, P)  # k is not a class



TypeError: issubclass() arg 1 must be a class



>>> isinstance(K, type)  # a class is an instace of type

True

>>> isinstance(k, type)  # not a class

False

get line break type (mac, linux, win and binary file)

jonasraoni (Jonas Raoni Soares Silva) — Sat, 02 Jul 2005 03:45:22 GMT

this code analyses the first 5*1024 bytes of data from a file and tells which break type it uses, or if it's a binary file...



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com



type

  TBreakType = ( btNone, btWin, btMac, btLin, btBin );



---------



function GetBreakType( const Filename: string; const MaxDataToRead: Cardinal = 5*1024 ): TBreakType;

var

  FS: TFileStream;

  Buffer, BufferStart, BufferEnd: PChar;

begin

  Result := btNone;

  if not FileExists( Filename ) then

    raise Exception.Create( 'GetBreakType: nome de arquivo inválido' );

  try

    FS := TFileStream.Create( Filename, fmOpenRead );

    GetMem( Buffer, MaxDataToRead+1 );

    BufferEnd := ( Buffer + FS.Read( Buffer^, MaxDataToRead ) );

    BufferStart := Buffer;

    BufferEnd^ := #0;

  except

    raise Exception.Create( 'GetBreakType: erro alocando memória.' );

  end;

  try

    while Buffer^ <> #0 do begin

      if Result = btNone then

        if Buffer^ = ASCII_CR then begin

          if (Buffer+1)^ = ASCII_LF then begin

            Result := btWin;

            Inc( Buffer );

          end

          else

            Result := btMac;

        end

        else if Buffer^ = ASCII_LF then

          Result := btLin;

      Inc( Buffer );

    end;

    if Buffer <> BufferEnd then

      Result := btBin;

  finally

    FreeMem( BufferStart, MaxDataToRead+1 );

    FS.Free;

  end;

end;