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Re: Implementing a array assignment for custom data structure

• To: mathgroup at smc.vnet.net
• Subject: [mg88892] Re: Implementing a array assignment for custom data structure
• From: Oliver Ruebenkoenig <ruebenko at uni-freiburg.de>
• Date: Tue, 20 May 2008 06:53:18 -0400 (EDT)
• References: <g0tqub$mj9$1@smc.vnet.net>

Salvatore,

I am not sure I understand entirely what you are looking for, but how 
about

In[1]:= mkFun[a_] := fun[a]

In[2]:= b=mkFun[1]

Out[2]= fun[1]

In[3]:= b

Out[3]= fun[1]

In[4]:= b[[1]]=2

Out[4]= 2

In[5]:= b

Out[5]= fun[2]


Oliver



On Tue, 20 May 2008, Salvatore Mangano wrote:

> Lists support a convenient syntax for element assignment:
>
> a[[i]]=v
>
> Of course this syntax is syntactic sugar for:
>
> Set[Part[a, i], v]
>
>
> SparseArray's have a different structure than lists but still support the same syntax.
>
> This leads me to believe that I should be able to implement a custom type (akin to SparseArray) that also allows this syntax (possibly using UpValues) but for the life of me I can't see how to accomplish this.
>
> Any ideas?
>
>

Oliver Ruebenkoenig, <ruebenko AT uni-freiburg.de>