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Date: Tue, 2 Jul 2013 10:29:44 -0700
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Subject: Re: On Alternative View Engines
From: Russell Branca <chewbranca@apache.org>
To: dev@couchdb.apache.org
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On Tue, Jul 2, 2013 at 10:07 AM, Alexander Shorin <kxepal@gmail.com> wrote:

> On Tue, Jul 2, 2013 at 8:31 PM, Russell Branca <chewbranca@apache.org>
> wrote:
> > I like the link to JSON Pointer, Alexander, that's intriguing. Something
> > like that could be very useful for simple views, although the RFC is
> quite
> > vague on edge cases, ie how would you implement something like if
> (doc.type
> > == "foo") emit(doc.bar, doc.baz) with JSON pointer. Speaking of JSON
> > pointer, looks like Jan beat us to the punch ;-)
> > https://github.com/janl/erl-jsonpointer
>
> JSON Pointer suggest to raise an error in case if pointer points to
> the non existed value.
> Probably, this case in DDL context will be like:
>
>   with doc emit /bar, /baz if /type is "foo"
>
> loops:
>
>   with doc map(emit(/bar, /baz) for foo in /boo if /bar is null break)
>
> a bit pythonic, but please don't shoot (:
>
> --
> ,,,^..^,,,
>

Sure, so we can create a DDL or what have you, but unless I'm missing
something, I don't see a way to make a view that filters on doc.type or
some other field, and then emits a simple set of values, which I think is
required for a minimal view implementation. The idea of JSON pointers where
we can just let users define path strings for the key and value is really
intriguing, but missing functionality.


-Russell

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