Re: structs/records in mathematica
- To: mathgroup at smc.vnet.net
- Subject: [mg41797] Re: structs/records in mathematica
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 6 Jun 2003 09:50:30 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <bbmu1h$iq$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
there is no "standard way" but you may do
something like:
MyData[id_,value_,compound_]
and define the functions
IdNumber[m_MyData]:=m[[1]]
Value[m_Mydata]:=m[[2]]
Compound[m_MyData]:=m[[3]]
Regards
Jens
Sidney Cadot wrote:
>
> Hi All,
>
> Currently I am involved in a project to read satellite data files into
> languages such as IDL and others. We're also considering implementing
> a Mathematica interface.
>
> For this application, we need the ability to represent classical
> records/structs (as found in imperative languages such as C/Pascal),
> having named fields with an associated value.
>
> Since such a type is not directly supported in Mathematica, we'd like
> to know if there is a 'standard' way of handling this type of
> situation.
>
> We're currently thinking of using a list of rules, e.g.
>
> data = {
> id->"this_or_that",
> value->17.3,
> compound->{id->"compound_id", value->18.4}
> }
>
> but this makes selecting a value a bit awkward:
>
> value/.(compound/.data)
>
> since this is syntactically the reverse of what one would expect in a
> language like C/Pascal (data.compound.value), and the /. operator is
> left-associative (therefore requiring parentheses in case of nested
> structs).
>
> Is there perhaps a better way/standard idiom for handling situations
> like this?
>
> Best regards,
> Sidney Cadot
> Science and Technology Corp., The Netherlands