| OCR Text |
Show iO ro?pns a level rorr objects to attribGe5 e entirely arcitrary. In terms of inforrration content, the arres tc adress oointers. This decison is based o tte cage in scale and caracter tetween obiec:s a:-:c attributes. otjects are usally farly larqe collections of inforation and are defined such tha: they rray be anipulated independently fro each other. It 15 thus reasoale to :equire otjects to carry a unique idet:fier hich is used as a lnkage echanis. .ttr i bu t e s , on the other han, are smaller collections of inforation and they can be ffianipulated only by accessing the oeject of which they are a part. Sinc& this access involves transferring the objec: into the program orkspace, each attribute will have a relative address in that workspace. tl;oreover, attribtes re;resent detail level information and are thus ot as easily syrrtolic31ly naed as oejects. T::e "n arr.s s " cr :he ?Oit5 cf a pclyhero, fer exaITple, wcld be "pc i r. ; r:143" is no mo r e ne e n i nc f u l than the "c c i r t at location 10640". Rather than incrrig the extra overhead of forcing at:rieutes to carry syrrbolic identifiers, ;..' . c r.e ; r errory location in the workspace is used as the identifier. Te attribute definition has the following ferrr <attritute definition>: :=5ttribute |
