[getdns-api] Getting from dicts by subscript operator

[Joe Hildebrand (jhildebr)]

Please don't invent a new syntax.  Use RFC 6901.

http://tools.ietf.org/html/rfc6901


-- 
Joe Hildebrand







On 9/21/15, 11:54 AM, "spec on behalf of Goyal, Neel" <spec-bounces at getdnsapi.net on behalf of ngoyal at verisign.com> wrote:

>I like it - however I¹d suggest tweaking the syntax a bit:
>
>"replies_tree[0][header][ad]² would become "replies_tree[0].header.ad²
>
>
>So the bracket syntax indicates that it¹s an array index and then the dot
>specifier indicates it¹s a field within a dict.
>
>
>On 9/21/15, 12:26 PM, "spec on behalf of Wessels, Duane"
><spec-bounces at getdnsapi.net on behalf of dwessels at verisign.com> wrote:
>
>>Willem,
>>
>>I think this idea is really great!
>>
>>
>>> On Sep 18, 2015, at 2:13 AM, Willem Toorop <Willem at nlnetlabs.nl> wrote:
>>> 
>>> Dear getdns API designers,
>>> 
>>> Getting into the specific parts of getdns data structures (notably the
>>> response dict) can be cumbersome in C.  Take for example this
>>> (relatively short) example on how to get to the AD bit of the first
>>> reply of a response:
>>> 
>>> getdns_list *replies_tree;
>>> getdns_dict *reply;
>>> getdns_dict *header;
>>> uint32_t     ad;
>>> 
>>> if ((r = getdns_dict_get_list(resp, "replies_tree", &replies_tree)))
>>> 	return r;
>>> else if ((r = getdns_list_get_dict(replies_tree, 0, &reply)))
>>> 	return r;
>>> else if ((r = getdns_dict_get_dict(reply, "header", &header)))
>>> 	return r;
>>> else if ((r = getdns_dict_get_int(header, "ad", &ad)))
>>> 	return r;
>>> 
>>> 
>>> Also, getting data members by text strings like getdns does, is
>>> unconventional in C libraries, but makes getdns very flexible and easy
>>> to extend.  It also maps very well to modern scripting languages
>>> (python, javascript, perl, ruby etc.).
>>> 
>>> Why don't we take this approach one step further, and get to the data
>>> members by allowing the text strings to contain subscript operators into
>>> the sub-dicts and sub-lists?
>>> 
>>> To do the same as the example above with subscript operator:
>>> 
>>> uint32_t ad;
>>> 
>>> if ((r = getdns_dict_get_int(resp, "replies_tree[0][header][ad]", &ad)))
>>> 	return r;
>>> 
>>> The conciseness and thereby clarity and readability is increasingly more
>>> prominent with more involved examples.
>>> 
>>> 
>>> What do you think?
>>> 
>>> -- Willem
>>> _______________________________________________
>>> spec mailing list
>>> spec at getdnsapi.net
>>
>
>
>_______________________________________________
>spec mailing list
>spec at getdnsapi.net