Re: Re: Re: Types in Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg62886] Re: [mg62879] Re: [mg62805] Re: Types in Mathematica*From*: Zhengji Li <zhengji.li at Gmail.com>*Date*: Thu, 8 Dec 2005 00:04:12 -0500 (EST)*References*: <dlp2ci$le$1@smc.vnet.net> <dls4vp$mmc$1@smc.vnet.net> <dm1ak3$i1n$1@smc.vnet.net> <dmjrb8$5u6$1@smc.vnet.net> <dmm2tp$nmo$1@smc.vnet.net> <dmrt6i$6le$1@smc.vnet.net> <200512032352.SAA15917@smc.vnet.net> <dmui9j$ml5$1@smc.vnet.net> <200512051841.NAA21160@smc.vnet.net> <200512070412.XAA23867@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Such a hot topic here. But what does "type" mean on earth? I define an integer "i". Then I do some arithmetic with it. Here, "i"'s type is "integer". In a programming language (like C), I write: int i; i = 1234; As the programmer, I do not care how the language implements "integer". It can use a register, or several bytes in memory (the ASCII code of "1234", or in Binray Code Decimal) to represent it. Let me guess, "types" should be considered in two layers: abstract layer and phsical layer. An integer "i" on abstract layer can be represented as an integer in tradition meaning or something else as you like on phyiscal layer. When I got a string "1234" on phsical layer, I can "abstract" it to an integer 1234. This is the mapping of types between the two layers. Turn to Mathematica, I define a symbol "a", it is completely a "symbol", it can be anything. This may be a try of Mathematica to represent things on the abstract layer. -- Li Zhengji ------------------------------------------------------------- If all you have is a hammer, everything is a nail. -------------------------------------------------------------

**References**:**Re: Types in Mathematica***From:*Paul Abbott <paul@physics.uwa.edu.au>

**Re: Re: Types in Mathematica***From:*Ed Peschko <esp5@pge.com>