How to use the new DataStructure in V 12.1 as is done in classical struct?

Question

There is new DataStructure in V 12.1. I thought at first it is similar to classical struct or record found in other languages and discussed in

Struct equivalent in Mathematica?

How to use classical data structure in Mathematica

Wikipedia entry for struct is https://en.wikipedia.org/wiki/Struct_(C_programming_language)

To make this question concrete, suppose one wants to make this struct, which in C is

struct personal_info 
{ 
   char name[50]; 
   int  age; 
   char address[50]; 
};

Then make a variable of the above type and access the struct fields using the dot notation in C. This is similar to record in Pascal and Ada also.

How to use the new DataStructure to do this? In C one will do something like the following

struct personal_info my_info;   
my_info.age = 90;
fprintf("my age is %d",my_info.age);

I could not find one basic example in the help pages on how to actually use this new DataStructure. I also looked at Wolfram blog on this, where he says

https://writings.stephenwolfram.com/2020/03/in-less-than-a-year-so-much-new-launching-version-12-1-of-wolfram-language-mathematica/

Think about all those data structures that get mentioned in textbooks, papers, libraries, etc. Our goal is to have all of them seamlessly usable directly in the Wolfram Language, and accessible in compiled code, etc. Of course it’s huge that we already have a universal “data structure”

But following Wolfram's examples on his blog, I still do not know how to make such a simple struct using Datastruct (I am not looking at queues or linked list, or other advanced structs, just the basic and most common struct).

So I tried few random things (when all else fails, I switch to the trial and error method)

ds = CreateDataStructure["DynamicArray"]
ds["Append", {"name" -> "doe joe", "age" -> 90, 
  "Address" -> "POBox 100, main street, California"}]; 

I used DynamicArray above, as I did not know what else to pick for classical struct.

But I do not think this is right at all, as I do not know now how to obtain say the name back.

Ofcourse one can use Association for this now in Mathematica, but I thought the new DataStructure will do this a little easier.

Question is: How to use new DataStructure similar to how it is used in C?

Answer 1

I think that the best match to what you are discussing is an association, e.g.

personalinfo = Association["name" -> "Fred", "age" -> 90]
(* <|"name" -> "Fred", "age" -> 90|> *)

personalinfo["name"]
(* "Fred" *)