[getdns-api] Getting from dicts by subscript operator

[Goyal, Neel]

Wasn’t trying to - just used what JavaScript does to access JSON.
Property and index accessors seem easy enough esp since we don’t have
weird characters in field names.  If a spec already exists for this sort
of thing, go for it.

On 9/21/15, 2:09 PM, "Joe Hildebrand (jhildebr)" <jhildebr at cisco.com>
wrote:

>Please don't invent a new syntax.  Use RFC 6901.
>
>http://tools.ietf.org/html/rfc6901
>
>
>-- 
>Joe Hildebrand
>
>
>
>
>
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>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
>>>
>>
>>
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